Unveiling Piperazine-Quinoline Hybrids as Potential Multi-Target Directed Anti- Alzheimer’s Agents: Design, Synthesis and Biological Evaluation

Unveiling Piperazine-Quinoline Hybrids as Potential Multi-Target Directed Anti- Alzheimer’s Agents: Design, Synthesis and Biological Evaluation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Unveiling Piperazine-Quinoline Hybrids as Potential Multi-Target Directed Anti- Alzheimer’s Agents: Design, Synthesis and Biological Evaluation Afzal Nagani, Moksh Shah, Salman Patel, Harnisha Patel, Vruti Parikh, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4098574/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Multi-target directed ligands (MTDLs) have recently been popularized due to their outstanding efficacy in combating the complicated features of Alzheimer's disease. This study details the synthesis of piperazine-quinoline-based MTDLs through a multicomponent Petasis reaction, targeting multiple factors such as AChE, BuChE, metal chelation to restore metal dyshomeostasis, and antioxidant activity. Some of the synthesized compounds exhibited notable inhibitory activity against AChE and BuChE enzymes at specific concentrations. Among the synthesized compounds compound ( 95 ) containing a 4-chloroaniline moiety and a 4-methoxybenzyl group displayed the most promising inhibitory activities against AChE (IC 50 3.013 µM) and BuChE (IC 50 = 3.144 µM). Compound ( 83 ) featuring 2-methoxyaniline and 4-fluorobenzyl substituents, exhibited the highest BuChE inhibition (IC 50 1.888 µM). Notably, compound ( 79 ) demonstrated 93-times higher selectivity for BuChE over AChE. Out of these compounds nine compounds were assessed for antioxidant activity, displaying significant potential at a concentration of 100 μM. Moreover, all the compounds demonstrated metal chelating activity with Cu +2 , Zn +2 , Fe +2 , Fe +3 and Al +3 . This study provides insights into the design of novel MTDLs, highlighting compound ( 95 ) as a potential candidate for Inhibiting Alzheimer's disease and emphasizing its role in the development of anti-AD medication. Piperazine Quinoline Acetylcholinesterase Butyrylcholinesterase Metal chelation Antioxidant Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Alzheimer's disease (AD) is a neurodegenerative disorder characterized by memory loss and dementia which poses a significant global health challenge accounting for more than 55 million cases worldwide, with nearly 10 million new cases emerging annually. The disease is named after a German psychiatrist Alois Alzheimer who first described it in the year 1906 [ 1 – 3 ]. The exact etiology of the disease still remains unknown. Certain hypotheses, such as deposition of β-amyloid (Aβ) plaques in the neurons, increase in the levels of acetylcholinesterase and butyrylcholinesterase neurotransmitters, neurofibrillary tangles (NFT), tau protein hyperphosphorylation, dyshomeostasis of biometals, and oxidative stress have been proposed as the causative factors for the genesis of the disease. Currently, a limited number of drugs are available to treat Alzheimer’s disease which include donepezil, rivastigmine, galantamine (all acetylcholinesterase inhibitors) and memantine, an N -methyl- D -aspartate (NMDA) receptor antagonist [ 4 ], that can either temporarily delay clinical deterioration or improve the symptoms associated with AD (Fig. 1 ). Due to the involvement of multiple factors in AD, the conventional approach of “one molecule one target” pattern proves inadequate for the management of the disease. Hence, an appropriate strategy for developing multi-targeted directed therapy could be adopted to counter the causative factors involved in the pathogenesis of AD [ 5 ]. Acetylcholine (ACh) a neurotransmitter, vital for cognitive functions including memory and physiological regulation, is found in the synapses of the neurons. ACh is broken down into acetic acid and choline, primarily by the enzyme acetylcholinesterase (AChE) and, to a lesser extent by butyrylcholinesterase (BuChE) secreted by glial cells. AChE's interaction with nonamyloidogenic amyloid-β (Aβ) motivated the researchers to target the AChE in cognitive disorder studies [ 6 ]. In a healthy brain, Ach is hydrolyzed by AChE, but with progression of the Alzheimer’s, the level of AChE drops, and the level of BuChE enhances by 40 to 90% in the brain's hippocampus and temporal cortex areas. BuChE is also correlated with the abnormal β-amyloid (Aβ) deposition [ 7 ]. Therefore, BuChE can be a promising target for the development of novel drugs for the treatment of AD [ 8 , 9 ]. As the brain ages, body’s antioxidant defense mechanism weakens and an imbalance in reactive oxygen species (ROS) production occurs, increasing the risk of AD. Oxidative stress aggravates AD’s progression leading to the formation of amyloid plaques and neurofibrillary tangles in the brain. To tackle AD, researchers are focusing on reducing the levels of free radicals in the brain. Recent research has revealed the therapeutic potential of compounds that can simultaneously inhibit AChE, disaggregate amyloid beta, and reduce inflammation. This multifaceted approach targets multiple aspects of AD's origin and progression, offering new avenues for developing anti-Alzheimer's therapeutics [ 10 – 12 ]. AD is marked by higher levels of metal ions in the brain which include Cu + 2 , Zn + 2 , Fe + 2 , Fe + 3 and Al + 3 , with particular emphasis on Cu + 2 and Zn + 2 . These metals readily bind to Aβ, causing toxic Aβ oligomer aggregation in the brain [ 13 , 14 ]. Iron is instrumental in impacting neurotransmitters, oxygen transport, cellular respiration, and DNA synthesis in the brain [ 15 ]. Elevated levels of iron are found in brain-damaged areas of AD patients, correlating significantly with Aβ plaques and Tau pathology [ 16 , 17 ]. Zinc, the second most abundant trace element in the human body after iron, also plays a role in AD. A meta-analysis from 1984 to 2014 showed decreased serum zinc levels in AD individuals [ 18 ]. Conversely, increased Zn levels in the cerebral cortex are associated with Aβ pathology and severity of dementia [ 19 ]. Research in recent years, has explored the link between AD and abnormal copper (Cu) metabolism. Genetic evidence suggests that genes regulating copper pathways contribute to AD susceptibility, which is supported by various studies [ 20 – 22 ]. Variations in copper levels in serum, plasma, cerebrospinal fluid (CSF) and the brain are linked to cognitive deficits and AD development [ 23 ]. 2. Designing Strategy Structure-based drug design approach was used to design new multi-target directed ligands as promising anti-Alzheimer’s agents. Piperazine scaffold has displayed versatile applications and played a vital role in drug discovery. It is associated with molecules exhibiting various activities such as anti-cancer, anti-diabetic, anti-histaminic, anti-Alzheimer’s, and also it has shown improved ADME properties along with better BBB penetration when incorporated into a molecular system. Piperazine, a bioisostere of piperidine, has been used to mimic the piperidine ring present in donepezil, and many piperazine-based AChE inhibitors have been developed, such as a piperazine derivative FK960, which has shown beneficial effects in memory deficits in Alzheimer's rats and monkeys [ 24 – 29 ]. Therefore, in the current study we have designed some novel molecules by incorporating piperazine into a molecular frame work utilizing multi-component Petasis reaction in the synthetic scheme. Quinoline is a privileged scaffold present in a wide variety of natural and synthetic compounds demonstrating an array of pharmacological properties. Quinoline derivatives have been found to possess a range of biological activities, such as anti-cancer, anti-malarial, analgesic, anti-tubercular, anti-bacterial, anti-protozoal, anti-glycemic, anti-inflammatory, anti-fungal, anti-hypertensive, anti-HIV, and anti-helminthic [ 30 , 31 ]. Recent research indicates that certain quinoline derivatives possess significant anti-acetylcholinesterase (AChE) and anti-butyrylcholinesterase (BuChE) effects. Molecular docking studies suggest that the quinoline fragment can bind to the peripheral anionic site (PAS) of AChE through π-π stacking interaction [ 32 ]. Also, the reported metal chelation property of quinoline in desferrioxamine [ 33 ], clioquinol (CQ) [ 34 ], and 8-hydroxyquinoline derivative (PBT2) [ 35 ] makes quinoline a potential molecular framework for anti-Alzheimer's drug discovery crusade [ 36 ]. Hence, in the present study, we report the design and development of some piperazine-quinoline analogs as multi-target directed ligands (MTDLs) using multicomponent Petasis reaction, which may open new horizons for a fundamentally novel treatment for Alzheimer's disease (AD). These MTDLs were evaluated for their efficacy for AChE inhibition, BuChE inhibition, metal chelation, and antioxidants. The designing strategy is being displayed in Fig. 2 . 3. Results and discussion 3. 1 Molecular Docking To validate the rationale behind the design of the hybrid molecules the designed compounds and some reference molecules were subjected to molecular modeling studies ( Figure 3 ) . Molecular docking studies were performed to check drug-receptor interactions, which are responsible for binding the ligands to the target proteins leading to enzyme inhibitory activity by the designed molecules. Hence, different interactions between the ligands and the target proteins were analyzed. The molecular superposition approach was validated by comparison with the original crystallographic structure of the AChE-Donepezil complex (PDB ID 7E3H) ( Human ) [37], and BuChE-Tacrine complex (PDB ID 4BDS) ( Human ) [38]. The most accurately positioned slots obtained were assessed. The outcomes are depicted in Figure 3 , demonstrating the alignment of the proposed binding modes for the inhibitors within the active sites of AChE and BuChE. This alignment yielded a superposition RMSD of 1.07 Å for donepezil (PDB ID 7E3H) [37] and 0.70 Å for Tacrine (PDB ID 4BDS) [2, 38]. These values fall very much within the widely accepted tolerance threshold of 2.0 Å. The study employed molecular docking with AutoDock Tools 1.5.7 and AutoDock Vina to calculate the binding energies of the synthesized ligands with the target proteins, acetylcholinesterase ( h AChE, PDB ID: 7E3H) [38] and butyrylcholinesterase ( h BuChE, PDB ID: 4BDS) [37]. The results are summarized in Table 1 , revealing the docking scores of the designed compounds ranging from -12.6 kcal/mol to -9.4 kcal/mol for h AChE and - 12.4 kcal/mol to -10.3 kcal/mol for BuChE respectively. Table 1: Docking score of the designed compounds for h AChE & h BuChE Comp. Affinity (kcal/mol) Comp. Affinity (kcal/mol) h AChE (7E3H) h BuChE (4BDS) h AChE (7E3H) h BuChE (4BDS) 71 -10.2 -11.7 86 -12.5 -11.1 72 -9.6 -12.2 87 -12.3 -11.2 73 -11.3 -11.2 88 -12.1 -11.5 74 -12.1 -11.7 89 -11.8 -11.7 75 -10.8 -11.4 90 -11.2 -12.1 76 -12.4 -11.4 91 -12.2 -11.3 77 -9.4 -10.9 92 -9.3 -11.7 78 -12.5 -10.9 93 -11.0 -10.3 79 -10.9 -11.2 94 -11.2 -11.5 80 -12.3 -11.8 95 -11.1 -11.1 81 -11.3 -12.4 96 -12.6 -11.0 82 -12.1 -11.4 97 -11.0 -11.3 83 -12.1 -11.8 Tacrine - -8.4 84 -12.1 -10.7 Donep-ezil -11.4 - 85 -9.6 -11.7 The findings indicated that all of the designed compounds assumed a consistent configuration when binding to AChE and BuChE enzymes, engaging with various amino acid fragments present in the enzymes’ catalytic active sites (CAS) and peripheral anionic sites (PAS) ( Tables 2 and 3 ). The findings demonstrated that all the compounds exhibited favorable fitting into the catalytic active site (CAS) and displayed effective interactions with the peripheral anionic site (PAS) of AChE and showed good binding affinity, akin to the reference inhibitor donepezil (-11.4 kcal/mol), as depicted in Figure 4 . Upon close examination of the compounds, it was observed that in the PAS, the amino acid residues TYR341 and TRP286 were engaged in π-π stacking interactions with the quinoline ring of the designed molecules. Additionally, SER289 and ARG289 formed hydrogen bonds, while PHE331 participated in π-π stacking. TRP84 and GLN69 were also involved in hydrogen bonding. Furthermore, amino acid residues SER125 and GLY121 in the CAS, interacted via hydrogen bonding with the oxygen atom of the amide linker. In the mid gorge region, TRP86 was involved in π-π stacking and TYR337 in π-sigma bonding. Other amino acid residues, including GLU202, PHE288, ASP74, and GLY448 also contributed to favorable interactions with the molecules. Figure 5 and Table 2 depicting amino acid interactions of in vitro most active compound 95 and compound having lowest binding energy 96 for AChE. Table 2: Docking scores and amino acid interactions of the standard drug donepezil and compounds ( 95 & 96 ) in the specific regions of h AChE (7E3H). Compound Score Interaction with the amino acid fragments Peripheral anionic site (PAS) Catalytic active site (CAS) Mid-gorge Donepezil -11.4 TRP286, TYR341, PHE295, VAL294 TRP86, TYR337, TYR72, PHE228 95 -11.1 TRP286, TYR341 GLY448, GLY121 PHE338 96 -12.6 TRP286, PHE330 SER125 TRP86, TYR337 In case of BuChE, docking scores of the designed compounds ranged from -12.4 kcal/mol to -10.3 kcal/mol. Further analysis of the interactions between the designed compounds and the protein was conducted. The results showed that all designed compounds effectively occupied the catalytic active site (CAS) and interacted favorably with the peripheral anionic site (PAS) of BuChE, mirroring the behavior of the reference inhibitor tacrine (-8.4 kcal/mol). Upon closer examination of all of the designed compounds, it was observed that the amino acid residue TRP231 was engaged in a π-alkyl interaction with the designed molecules in the PAS. Additionally, LEU286 and PHE329 fragments exhibited π-alkyl interactions in the mid-gorge region of the enzyme, and GLY116 and GLY119 also showed interactions in the same region. In the CAS, amino acid residues TRP82 and HIS438 displayed π-π stacking interactions with the quinoline ring, ALA328 displayed π-alkyl interaction, and many compounds displayed interactions with MET437 and TYR440 residues of the CAS region. Figure 6 and Table 3 depicting amino acid interactions of in vitro most active compounds 83 and 92 for BuChE. Table-3: Docking score and amino acid interactions of the standard drug tacrine and the compounds ( 83 & 92 ) in the specific regions of BuChE (4BDS). Compound Score Interaction with the amino acid fragments Peripheral anionic site (PAS) Catalytic active site (CAS) Mid-gorge Tacrine -8.4 TRP231 HIS438, SER198 GLY116, GLY117, PHE329 83 -11.2 TRP231 TRP82, HIS438, TYR440, SER198 LEU286, PHE329, GLY117, GLY119 92 -11.8 TRP231 TRP82, HIS438, SER198 GLY116, GLY117, LEU286, PHE329 3.2 Chemistry The designed compounds were synthesized using a sequence of reactions as shown in Scheme-1 . N-Boc -piperazine ( 1 ), glyoxalic acid ( 3 ), and boronic acids ( 2a – 2c ) were reacted in the first step utilizing Petasis-Mannich multicomponent reaction in the presence of ACN solvent to obtain the intermediates ( 4 - 6 ). In step 2, these intermediates were coupled with substituted aromatic/cyclic amines ( 7 – 15 ) through acid-amine coupling reaction in the presence of EDC.HCl, HOBt and triethylamine to obtain the amides ( 16 – 42 ), followed by deprotection of Boc using dioxane HCl. The designed compounds were obtained by reacting the resulting intermediates ( 43 – 69 ) with 5-chloromethyl-8-hydroxyquinoline ( 70 ) in the presence of triethylamine at 100 o C in the presence of DMSO as a solvent. The chloromethyl derivative ( 70 ) was obtained by chloromethylation of 8-hydroxyquinoline using formaldehyde and hydrogen chloride gas. 3.3 Anti-Alzheimer’s Activity All of the synthesized piperazine derivatives ( 71 – 79, 80 – 88, and 89 – 97 ) were evaluated for anticholinesterase activity against human AChE and equine BuChE enzymes, and for their metal chelation and antioxidant properties to determine their potential application against Alzheimer’s disease. AChE and BuChE inhibitory assays were performed by Ellman’s enzyme assay where we determined the IC 50 values of all the designed compounds and compared them with standard drugs, donepezil for AChE inhibition and tacrine for BuChE inhibition. Anti-oxidant activity of nine compounds were evaluated using the DPPH method with ascorbic acid as the reference compound. The metal chelation potential of the synthesized compounds was assessed for the biologically significant metal ions such as Fe +2 , Fe +3 , Cu +2 , Zn +2 , and Al +3 . The results indicated that most of the compounds showed moderate AChE inhibitory activity but excellent BuChE inhibitory activity. These compounds also exhibited significant antioxidant and metal chelating properties. 3.4 Cholinesterase inhibitory activity IC 50 values of all the synthesized compounds were determined using Ellman’s essay. Human AChE enzyme was used for determining acetylcholinesterase inhibition and Equine BuChE enzyme was utilized for butyrylcholinesterase inhibitory activities. The synthesized compounds showed low to moderate IC 50 values for AChE inhibition, wherein twenty-seven compounds offered IC 50 values under 100 µM with compound ( 95) showing the highest activity with an IC 50 value of 3.013 µM . Compounds ( 81, 82 and 78 ) offered 50 % inhibition at concentrations of 8.06, 21.85, and 30.92 µM. It is important to note that substitution with electron releasing group (OCH 3 ) ( 89 - 97 ) or a small sized atom (F) ( 80 - 88 ) on the 4 th position of the benzyl ring shows improved activity compared to the un-substituted derivatives ( 71 - 79 ). Furthermore, substitution on the aniline ring also has a significant effect in improving or reducing the inhibitory activity whereby substitution with electron-withdrawing groups (Cl or F) on the 4 th position in the series containing 4-methoxybenzyl ring ( 89 – 97 ) showed improved activity with IC 50 values of 3.013 µM and 45.27 µM for compounds ( 95 and 89) . Additionally, attachment of electron releasing groups (CH 3 , and OCH 3 ) on ortho or para position in the series with electron-withdrawing group (F) on the benzyl ring showed excellent activity wherein ortho substitution of methyl (81) and methoxyl (83) groups showed IC 50 values of 8.056 and 14.09 µM respectively, and para substitution of methyl (82) group gave 50 % inhibition at 21.85 µM. Moreover, it is important to note that unsubstituted aniline or cyclohexamine showed the poorest activity against AChE enzyme. Hence, we can say that substitution of electron releasing or electronegative groups on both the rings, benzyl as well as aniline is important for activity . When both the functional groups are present in the compounds it offered significant AChE inhibition. For the butyrylcholinesterase inhibition, all the compounds exhibited excellent inhibitory activity with IC 50 values below 12.42 µM, with compounds containing o -methoxy substituent on the aniline ring showing the best IC 50 value of 1.88 µM for the 4-fluoro substituted benzyl derivative (83), 2.217 µM for 4-methoxy benzyl derivative (92), and 3.732 µM for unsubstituted benzyl derivative (74). 4-Chloro substituted aniline derivatives also showed excellent BuChE inhibition with IC 50 values of 5.182, 2.02, and 3.133 µM for compounds ( 77, 86 and 95) respectively. Notably, cyclohexylamino and unsubstituted anilino derivatives, which proved poor AChE inhibitors offered high selectivity for BuChE with low IC 50 values. The anilino derivative (71) showed an IC 50 value of 5.740 µM which was 25 times lower than the value obtained for AChE inhibition, whereas the cyclohexylamino derivative (79) offered 93 times higher selectivity for BuChE with an IC 50 of 2.288 µM . Anilino derivatives (80 and 89) accounted for IC 50 values of 8.17 and 5.94 µM respectively, and cyclohexylamino derivatives (88 and 97) yielded IC 50 values of 6.509 and 8.368 µM for compounds (88 and 97) yielding more than 18 times higher selectivity for butyrylcholinesterase. 3.5 Anti-oxidant and Metal chelation properties The antioxidant property was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of some selected compounds. Top nine cholinesterase inhibitors (78, 79, 81, 82, 83, 84, 86, 92 and 95) were evaluated for their antioxidant properties and the activities were compared with ascorbic acid as a standard. The essay was performed by taking 20-100 µg/ml concentrations of the test and the standard compounds and evaluated for inhibition of 0.1 mM DPPH free radicals. Results indicated that all the nine compounds showed inhibition wherein compounds ( 78, 83 and 86 ) have shown the highest activity amongst the screened compounds. These three compounds ( 78, 83 and 86 ) showed 42.13 %, 39.33 %, and 37.18 % inhibition respectively, at 20 µg/ml concentration against 52.54 % shown by the ascorbic acid. At 100 µg/ml concentration, 78 exhibited an inhibition of 55.17 %, and its IC 50 value was found to be 73.12 μg/ml , and 83 exhibited an inhibition of 52.91 %, and its IC 50 value was found to be 81.65 μg/ml . Similarly, 86 exhibited an inhibition of 51.4 % in the DPPH radical scavenging activity, and its IC 50 value was found to be 90.73 μg/ml . Ascorbic acid was used as a reference compound which exhibited a percent inhibition of 87.56 % and offered an IC 50 value of 13.98 μg/ml ( Table 5) . All the compounds displayed metal chelating ability with (Fe +2 , Fe +3 , Zn +2 , Cu +2 , and Al +3 ) due to the presence of 8-hydroxyquinoline moiety present in these molecules ( Table 4 ) Table 5: Antioxidant potential of compounds ( 78, 79, 81, 82, 83, 84, 86, 92 and 95 ) Compounds Concentration (µg/ml) IC 50 (µg/ml) 20 40 60 80 100 % Inhibition Ascorbic Acid 52.538 61.450 70.362 79.792 87.564 13.98 78 42.133 44.935 46.443 50.862 55.172 73.125 79 44.145 45.284 47.150 48.290 49.326 108.787 81 34.590 38.362 41.163 44.935 49.137 107.134 82 35.668 39.331 41.702 44.181 48.599 113.202 83 39.331 42.887 47.090 49.568 52.909 81.65 84 43.316 44.041 44.870 45.595 46.424 197.105 86 37.176 40.301 46.012 47.737 51.400 90.726 92 41.761 42.072 43.730 44.455 46.943 159.365 95 31.896 35.991 40.409 43.965 48.060 109.601 3.6 ADME Prediction In order to exhibit anti-Alzheimer activity, crossing of blood brain barrier by a test compound, is one of the key attributes, which was determined using SwissADME along with other key pharmacokinetic properties of the synthesized compounds. The results were promising, and all the compounds except compounds ( 74, 75, 78, 87, 92, 93 and 96) were found to cross BBB. Moreover, all the compounds indicated good bioavailability of 0.55 and high GI absorption. Thus, it could be said that twenty compounds out of the twenty-seven synthesized compounds, including those exhibiting promising in vitro cholinesterase inhibition, possess excellent pharmacokinetic properties and they have high probability to reach the active site and show anti-Alzheimer activity. 4. Experimental 4.1 Docking protocol The ADT software and Autodock vina program were employed for molecular docking to assess the interaction between the designed analogs and the targeted enzymes (AChE & BuChE). This was aimed to corroborate the findings from both in vitro and in silico analyses. Utilizing PDB codes 7E3H for AChE and 4BDS for BuChE from the RCSB protein databank (http://www.rcsb.org), crystal structures of the targets were retrieved. Autodock vina necessitates the ligand as well as the receptor in pdbqt format. The ADT software was utilized to prepare the two enzymes and the ligands. In the process of protein preparation, all water molecules were removed, followed by the addition of polar hydrogens and Kollman charges. Subsequently, active sites were determined by creating grid boxes sized 40 × 40 × 40 Å for AChE and for BuChE around the binding domains of each co-crystallized ligands with the respective enzyme coordinates: center_x = -43.36, center_y = 37.72, center_z = -30.31 for AChE, and center_x = 132.8, center_y = 115.68, center_z = 41.43 for BuChE. To validate the docking protocol, the docked ligands were removed from the co-crystallized structures, and re-docking both of the ligands, i.e. donepezil for AChE and tacrine for BuChE, followed by calculating the Root-Mean-Square Deviation (RSMD) between the co-crystalized ligands and the re-docked poses. For analysis of the docking results and visualization of ligand-receptor interactions, Discovery Studio 2021 client was employed. 4.2 Chemistry For the synthesis of compounds, all the chemicals were procured from Spectrochem PrivateLimited, Sigma Aldrich, and Avra Synthesis Private Limited.All the reagents and solvents used for the synthesis of the proposed compounds were purified using standard laboratory techniques prior to use. Progress of the reactions was monitored using pre-coated silica gel GF 254 TLC plates, and spots were visualized under UV light at 254 or 365 nm. Different solvent systems, like hexane-ethyl acetate (7:3 and 6:4) and dichloromethane-methanol (9:1 v/v), were used as eluents. A Rota evaporator (BUCHI R-300) was used for removing the solvents during the workups. Chromatographic purification was performed by column chromatography using Silica gel #100-200. Melting points of the compounds were measured using a digital melting point apparatus (Veego VMP-D) and were uncorrected. Bruker FT-IR, model ALPHA-T (Germany) spectrophotometer was used for recording the IR spectra of individual compounds (wave numbers in cm -1 ) using ATR. Molecular weights of the synthesized compounds were determined using a Mass spectrophotometer, (Waters Acquity QDA). 1 NMR data was collected using an NMR instrument (Bruker 400 MHz) in CDCl 3 or DMSO-d 6 solvents (TMS used as internal standard). Purity and composition of the compounds were confirmed by elemental analysis using Thermo Fisher FLASH 2000 organic elemental analyser. The analysed compounds offered results within ± 0.4 % of the theoretical values of carbon, hydrogen and nitrogen. 4.2.1 General Method for the Synthesis of Compounds (4 – 6 ): (Method-A) To a solution of 1-Boc-piperazine (2.0 g, 10.74 mM) and glyoxylic acid monohydrate (0.98 g, 10.74 mM) in acetonitrile (20 mL), the corresponding boronic acid (10.74 mM) was added. The reaction mixture was stirred at 85 °C for 16 h, and progress of the reaction was monitored by TLC using (10 % methanol in dichloromethane). After the consumption of the starting materials, the solvent was removed under reduced pressure, and the residue was washed with hexane, and purified by column chromatography using silica gel as a stationary phase to afford the desired products ( 4 - 6 ). 4.2.1.1 2-(4-(tert-Butoxycarbonyl)piperazin-1-yl)-2-phenylacetic acid ( 4 ): Prepared by Method A using phenylboronic acid (1.3 g, 10.74 mM) ( 2a ) to offer compound ( 4 ) as a white solid (3.22 g, 93.6 %), m.p. 180-183 o C; TLC (R f ): 0.50 (10 % Methanol in dichloromethane); IR: 3445, 2977, 2930, 1697, 1621, 1423, 1365, 1345, 1136, 1166, 1080, 965 cm -1 ; 1 H-NMR: δ 7.43-7.41 (d, 2H, Ar H ), 7.31-7.28 (m, 3H, Ar H ), 6.98 (s, 1H, Ar H ), 4.16 (s, 1H, C H ), 3.52-3.37 (m, 4H, C H 2 ), 2.73-2.66 (d, 4H, C H 2 ), 1.47-1.45 (d, 9H, CH 3 ); Mass (m/z): 321.2 (M+1). 4.2.1.2 2-(4-(tert-Butoxycarbonyl)piperazin-1-yl)-2-(4- fluorophenyl) acetic acid ( 5 ): Prepared by Method A using 4-fluorophenylboronic acid (1.5 g, 10.74 mM) ( 2b ) to offer compound ( 5 ) as a white solid (3.45 g, 95 %), m.p. 176-178 o C; TLC(R f ): 0.60 (10 % methanol in dichloromethane); IR: 3405, 2978, 2932, 1700, 1635, 1510, 1457, 1245, 1004, 757 cm -1 ; 1 H NMR δ 7.45-7.42 (m, 2H, Ar H ), 7.21-7.17 (m, 2H, Ar H ), 4.02(s, 1H, C H ), 3.31-3.30 (d, 4H, C H 2 ), 2.39-2.29 (m, 4H, C H 2 ), 1.37 (s, 9H, C H 3 ); Mass (m/z): 339.3 (M+1). 4.2.1.3 2-(4-(tert-Butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) : Prepared by Method A using 4-methoxyphenylboronic acid (1.63 g, 10.74 mM) ( 2c ) to offer compound ( 6 ) as a white solid (3.42 g, 90.95 %), m.p. 135-138 o C, TLC (R f ): 0.55 (10 % Methanol in dichloromethane); IR: 3422, 2931, 1700, 1617, 1517, 1461, 1412, 1259, 1134, 1038, 966, 869 cm -1 ; 1 H NMR δ 7.35-7.33 (d, 2H, Ar H ), 6.89-8.87 (d, 2H, Ar H ), 4.42 (s, 1H, C H ), 3.81 (s, 3H, OC H 3 ), 3.61 (s, 4H, C H 2 ), 2.83 (s, 4H, C H 2 ), 1.44 (s, 9H, C H 3 ); Mass (m/z): 351.2 (M+1). 4.3.1 General method for acid-amine coupling for preparing compounds ( 16 - 42 ) : (Method B) To a solution of the corresponding products ( 4 - 6 ) (1.0 g) in THF (10 mL), EDC.HCl (1 equiv), and HOBt (1 equiv) were added, and the reaction mixture was stirred at a temperature between 5-10 °C for a time period of 20 min. The corresponding aniline/substituted aniline (1 equiv) was added to the above solution followed by N,N- diisopropylethylamine (3 equiv). Stirring was continued at RT for 16 h and THF was removed under reduced pressure. The resulting residue was extracted in DCM and washed with water; the organic layer was removed under reduced pressure to obtain the desired products ( 16 - 42 ). 4.3.1.1 tert-Butyl-4-(2-oxo-1-phenyl-2-(phenylamino)ethyl)piperazine-1-carboxylate (16): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-phenylacetic (4) (1.0 g, 3.12 mM), and aniline (0.29 g, 3.12 mM) to obtain compound ( 16 ) as white solid (0.92 g, 74.79 %) m.p. 88-90 o C, TLC (R f ): 0.40 (20 % Ethyl acetate in hexane), IR: 3501, 3259, 2862, 1676, 1601, 1559, 1447, 1249, 1171, 735 cm -1 . 4.3.1.2 tert-Butyl-4-(2-oxo-1-phenyl-2-(o-tolylamino)ethyl)piperazine-1-carboxylate (17): Prepared by Method B using 2-(4-( tert- butoxycarbonyl)piperazin-1-yl)-2-phenylacetic (4) (1.0 g, 3.12 mM), and 2-methylaniline (0.33 g, 3.12 mM)) to obtain compound ( 17 ) as brown solid (0.89 g, 69.53 %), m.p. 84-87 o C, TLC (R f ): 0.42 (20 % Ethyl acetate in hexane), IR: 3362, 2926, 1691, 1587, 1521, 1454, 1365, 1286, 1169, 1003 cm -1 . 4.3.1.3 tert-Butyl-4-(2-oxo-1-phenyl-2-(p-tolylamino)ethyl)piperazine-1-carboxylate (18): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-phenylacetic (4) (1.0 g, 3.12 mM), and 4-methylaniline (0.33 g, 3.12 mM) to obtain compound ( 18 ) as brown solid (0.9 g, 70.31%), m.p. 80-82 o C, TLC (R f ): 0.44 (20 % Ethyl acetate in hexane), IR: 3326, 2974, 2857, 1706, 1668, 1597, 1452, 1364, 1287, 1170, 1018 cm -1 . 4.3.1.4 tert-Butyl-4-(2-((2-methoxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate (19): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-phenylacetic (4) (1.0 g, 3.12 mM), and 2-methoxyaniline (0.38 g, 3.12 mM) to obtain compound ( 19 ) as white solid (0.92 g, 69.17 %), m.p. 92-95 o C, TLC (R f ): 0.38 (20 % Ethyl acetate in hexane), IR: 3324, 2970, 2836, 1683, 1598, 1512, 1480, 1423, 1304, 1170, 1018 cm -1 . 4.3.1.5 tert-Butyl-4-(2-((4-methoxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate (20 ): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-phenylacetic (4) (1.0 g, 3.12 mM), and 4-methoxyaniline (0.38 g, 3.12 mM) to obtain compound ( 20 ) as white solid (0.94 g, 70.67 %), m.p. 98-100 o C, TLC (R f ): 0.38 (20 % Ethyl acetate in hexane), IR: 3307, 2974, 1692, 1601, 1514, 1456, 1165, 1170, 1129, 1033 cm -1 . 4.3.1.6 tert-Butyl-4-(2-((4-fluorophenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate (21 ): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-phenylacetic (4) (1.0 g, 3.12 mM), and 4-fluoroaniline (0.34 g, 3.12 mM) to obtain the desired product ( 21 ) as brown solid (0.92 g, 71.32 %), m.p. 68-70 o C, TLC (R f ): 0.46 (20 % Ethyl acetate in hexane), IR: 3504, 2978, 1677, 1623, 1576, 1426, 1409, 1289, 1172, 1005 cm -1 . 4.3.1.7 tert-Butyl-4-(2-((4-chlorophenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate (22 ): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-phenylacetic ( 4 ) (1.0 g, 3.12 mM), and 4-chloroaniline (0.39 g, 3.12 mM) to obtain compound ( 22 ) as brown solid (0.95 g, 70.89 %), m.p. 74-76 o C, TLC (R f ): 0.48 (20 % Ethyl acetate in hexane), IR: 3319, 2976, 2857, 1704, 1677, 1592, 1400, 1635, 1244, 1170, 1001 cm -1 . 4.3.1.8 tert-Butyl-4-(2-((4-hydroxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate (23 ): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-phenylacetic (4) (1.0 g, 3.12 mM), and 4-hydroxyaniline (0.34 g, 3.12 mM) was added to obtain compound ( 23 ) as brown solid (0.95 g, 74.21 %), m.p.104-107 o C, TLC (R f ): 0.32 (20 % Ethyl acetate in hexane), IR: 3295, 2975, 1690, 1607, 1514, 1247, 1169, 1132, 1005 cm -1 . 4.3.1.9 tert-Butyl-4-(2-(cyclohexylamino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate (24): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-phenylacetic (4) (1.0 g, 3.12 mM), and cyclohexanamine (0.30 g, 3.12 mM) was added to obtain compound ( 24 ) as white solid (0.98 g, 78.4 %), m.p. 88-90 o C, TLC (R f ): 0.40 (20 % Ethyl acetate in hexane), IR: 3304, 2931, 2856, 1696, 1658, 1527, 1452, 1405, 1288, 1120, 1006 cm -1 . 4.3.1.10 tert-Butyl-4-(1-(4-fluorophenyl)-2-oxo-2-(phenylamino)ethyl)piperazine-1-carboxylate (25): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid (5) (1.0 g, 2.95 mM), and aniline (0.27 g, 2.95 mM) was added to obtain compound ( 25 ) as white solid (0.91 g, 74.59 %) m.p. 82-84 o C, TLC (R f ): 0.52 (20 % Ethyl acetate in hexane), IR: 3308, 2976, 1690, 1600, 1507, 1440, 1366, 1247, 1169, 1027 cm -1 . 4.3.1.11 tert-Butyl-4-(1-(4-fluorophenyl)-2-oxo-2-(o-tolylamino)ethyl)piperazine-1-carboxylate (26): Prepared by Method B using 2-(4-( tert- butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid (5) (1.0 g, 2.95 mM), and 2-methylaniline (0.31 g, 2.95 mM) was added to obtain compound ( 26 ) as brown solid (0.76 g, 60.31 %), m.p. 94-97 o C, TLC (R f ): 0.48 (20 % Ethyl acetate in hexane), IR: 3309, 2924, 1693, 1601, 1510, 1421, 1285, 1366, 1168, 1001 cm -1 . 4.3.1.12 tert-Butyl-4-(1-(4-fluorophenyl)-2-oxo-2-(p-tolylamino)ethyl)piperazine-1-carboxylate (27): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid (5) (1.0 g, 2.95 mM), and 4-methylaniline (0.31 g, 2.95 mM) was added to obtain compound ( 27 ) as brown solid (0.82 g, 65 %), m.p. 97-99 o C, TLC (R f ): 0.50 (20 % Ethyl acetate in hexane), IR: 3316, 2976, 1692, 1600, 1512, 1457, 1421, 1285, 1127, 1001 cm -1 . 4.3.1.13 tert-Butyl-4-(1-(4-fluorophenyl)-2-((2-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate (28 ): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid (5) (1.0 g, 2.95 mM), and 2-methoxyaniline (0.36 g, 2.95 mM) was added to obtain compound ( 28 ) as white solid (0.98 g, 69.5 %), m.p. 78-81 o C, TLC (R f ): 0.45 (20 % Ethyl acetate in hexane), IR: 3305, 2976, 2853, 1682, 1603, 1511, 1417, 1247, 1107, 1035, 1003 cm -1 . 4.3.1.14 tert-Butyl-4-(1-(4-fluorophenyl)-2-((4-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate (29): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid (5) (1.0 g, 2.95 mM), and 4-methoxyaniline (0.36 g, 2.95 mM) was added to obtain compound ( 29 ) as brown solid (0.96 g, 68 %), m.p. 77-80 o C, TLC (R f ): 0.46 (20 % Ethyl acetate in hexane), IR: 3298, 2975, 1689, 1511, 1419, 1246, 1170, 1004 cm -1 . 4.3.1.15 tert-Butyl-4-(1-(4-fluorophenyl)-2-((4-fluorophenyl)amino)-2-oxoethyl)piperazine-1-carboxylate ( 30): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid (5) (1.0 g, 2.95 mM), and 4-fluoroaniline (0.32 g, 2.95 mM) was added to obtain compound ( 30 ) as brown solid (0.89 g, 70 %), m.p. 63-66 o C, TLC (R f ): 0.54 (20 % Ethyl acetate in hexane), IR: 3296, 2976, 2930, 1692, 1509, 1423, 1403, 1286, 1170, 1004 cm -1 . 4.3.1.16 tert-Butyl-4-(2-((4-chlorophenyl)amino)-1-(4-fluorophenyl)-2-oxoethyl)piperazine-1-carboxylate (31): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid (5) (1.0 g, 2.95 mM), and 4-chloroaniline (0.37 g, 2.95 mM) was added to obtain compound ( 31 ) the desired product as white solid (0.94 g, 71.21 %), m.p. 70-73 o C, TLC (R f ): 0.56, IR: 3383, 2927, 1695, 1599, 1511, 1406, 1369, 1223, 1158, 1004 cm -1 . 4.3.1.17 tert-Butyl-4-(1-(4-fluorophenyl)-2-((4-hydroxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate (32 ): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid (5) (1.0 g, 2.95 mM), and 4-hydroxyaniline (0.32 g, 2.95 mM) was added to obtain compound ( 32 ) as brown solid (0.92 g, 73 %), m.p. 112-114 o C, TLC (R f ): 0.35 (20 % Ethyl acetate in hexane), IR: 3294, 2976, 1688, 1666, 1511, 1424, 1366, 12487, 1131, 1001 cm -1 . 4.3.1.18 tert-Butyl-4-(2-(cyclohexylamino)-1-(4-fluorophenyl)-2-oxoethyl)piperazine-1-carboxylate (33): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid (5) (1.0 g, 2.95 mM), and cyclohexanamine (0.29 g, 2.95 mM) was added to obtain compound ( 33 ) as white solid (0.90 g, 72.58 %), m.p. 94-97 o C, TLC (R f ): 0.42 (20 % Ethyl acetate in hexane), IR: 3308, 2923, 2856, 1695, 1661, 1599, 1508, 1453, 1285, 1170, 1003 cm -1 . 4.3.1.19 tert-Butyl-4-(1-(4-methoxyphenyl)-2-oxo-2-(phenylamino)ethyl)piperazine-1-carboxylate (34): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) (1.0 g, 2.85 mM) and aniline (0.26 g, 2.85 mM) was added to obtain compound ( 34 ) as brown solid (0.92 g, 76 %), m.p. 112-115 o C, TLC (R f ): 0.58 (20 % Ethyl acetate in hexane), IR: 3307, 2974, 1692, 1601, 1511, 1441, 1247, 1174, 754 cm -1 . 4.3.1.20 tert-Butyl-4-(1-(4-methoxyphenyl)-2-oxo-2-(o-tolylamino)ethyl)piperazine-1-carboxylate (35 ): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) (1.0 g, 2.85 mM), and 2-methylaniline (0.30 g, 2.85 mM) was added to obtain compound ( 35 ) as brown solid (0.86 g, 68.8 %), m.p. 107-110 o C, TLC (R f ): 0.60 (20 % Ethyl acetate in hexane), IR: 3356, 2975, 1692, 1607, 1511, 1454, 1247, 1172, 1002 cm -1 . 4.3.1.21 tert-Butyl-4-(1-(4-methoxyphenyl)-2-oxo-2-(p-tolylamino)ethyl)piperazine-1-carboxylate (36): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) (1.0 g, 2.85 mM), and 4-methylaniline (0.30 g, 2.85 mM) was added to obtain compound ( 36 ) as white solid (0.70 g, 70.4 %), m.p. 104-105 o C, TLC (R f ): 0.60 (20 % Ethyl acetate in hexane), IR: 3303, 2930, 2855, 1688, 1643, 1509, 1242, 1168, 1120 cm -1 . 4.3.1.22 tert-Butyl-4-(1-(4-methoxyphenyl)-2-((2-methoxyphenyl)amino)-2-oxoethyl)- piperazine-1-carboxylate (37): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) (1.0 g, 2.85 mM), and 2-methoxyaniline (0.35 g, 2.85mM) was added to obtain compound (37 ) as white solid (0.89 g, 68.46 %), m.p. 98-101 o C, TLC (R f ): 0.54 (20 % Ethyl acetate in hexane), IR: 3333, 2929, 2852, 1689, 1608, 1510, 1242, 1168, 1026 cm -1 . 4.3.1.23 tert-Butyl-4-(1-(4-methoxyphenyl)-2-((4-methoxyphenyl)amino)-2-oxoethyl)piperazine -1-carboxylate (38): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) (1.0 g, 2.85 mM), and 4-methoxyaniline (0.35 g, 2.85 mM) was added to obtain compound ( 38 ) as white solid (0.95, 73 %), m.p. 95-97 o C, TLC (R f ): 0.54 (20 % Ethyl acetate in hexane), IR:3334, 2929, 2852, 1688, 1645, 1509, 1403, 1242, 1168, 1027 cm -1 . 4.3.1.24 tert-Butyl-4-(2-((4-fluorophenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate (39 ): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) (1.0 g, 2.85 mM), and 4-fluoroaniline (0.31 g, 2.85 mM) was added to obtain compound ( 39 ) as white solid (0.92 g, 73 %), m.p. 94-95 o C, TLC (R f ): 0.56 (20 % Ethyl acetate in hexane), IR: 3305, 2974, 1690, 1611, 1511, 1458, 1248, 1172, 1033 cm -1 . 4.3.1.25 tert-Butyl-4-(2-((4-chlorophenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate (4 0): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) (1.0 g, 2.85 mM), and 4-chloroaniline (0.36 g, 2.85 mM) was added to obtain compound ( 40 ), the desired product as brown solid (0.98 g, 74.8 %), m.p. 108-110 o C, TLC (R f ): 0.62 (20 % Ethyl acetate in hexane), IR: 3428, 2975, 1685, 1594, 1511, 1412, 1247, 1171,1008 cm -1 . 4.3.1.26 tert-Butyl-4-(2-((4-hydroxyphenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)- piperazine-1-carboxylate (41): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) (1.0 g, 2.85 mM), and 4-hydroxyaniline (0.31 g, 2.85 mM) was added to obtain compound ( 41 ), the desired product as brown solid (0.93 g, 73.8 %), m.p. 120-122 o C, TLC (R f ): 0.40 (20 % Ethyl acetate in hexane), IR: 3333, 2929, 2852, 1690, 1645, 1510, 1403, 1242, 1168, 1027 cm -1 . 4.3.1.27 tert -Butyl-4-(2-(cyclohexylamino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate (42 ): Prepared by Method B using 2-(4-( tert -butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid (6) (1.0 g, 2.85 mM), and cyclohexylamine (0.28 g, 2.85 mM) was added to obtain compound ( 42 ), the desired product as white solid (0.90 g, 73.1 %), m.p. 90-93 o C, TLC (R f ): 0.45 (20 % Ethyl acetate in hexane), IR: 3327, 2930, 2854, 1689, 1643, 1509, 1420, 1242, 1168, 1117 cm -1 . 4.4.1 General Method for Boc-deprotection: (43-69 ) : (Method C) To a solution of the corresponding products ( 16 - 42 ) in DCM (7.5 mL), dioxane-HCl (7.5 mL) (dioxane saturated with hydrogen chloride gas) was added and stirred at 25 o C for 3 h. The reaction was monitored on TLC, after the completion of the reaction, solvent was removed under reduced pressure to obtain sticky Products ( 43 - 69 ) which were used as such for the next step. 4.4.1.1 N,2-Diphenyl-2-(piperazin-1-yl)acetamide (43): tert -Butyl-4-(2-oxo-1-phenyl-2-(phenylamino)ethyl)piperazine-1-carboxylate ( 16 ) (0.75 g, 1.76 mM) through Method C offered the product ( 43 ) (0.54 g, 96.42 %). TLC (R f ): 0.51 (70 % Ethyl acetate in hexane). 4.4.1.2 2-Phenyl-2-(piperazin-1-yl)-N-(o-tolyl)acetamide (44): tert -Butyl 4-(2-oxo-1-phenyl-2-( o -tolylamino)ethyl)piperazine-1-carboxylate ( 17 ) (0.75 g, 1.76 mM) through Method C offered the product ( 44 ) (0.53 g, 94.64 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1. 3 2-Phenyl-2-(piperazin-1-yl)-N-(p-tolyl)acetamide (45): tert -Butyl 4-(2-oxo-1-phenyl-2-( p -tolylamino)ethyl)piperazine-1-carboxylate ( 18 ) (0.75 g, 1.76 mM), through Method C offered the product ( 45 ) (0.52 g, 92.85 %). TLC (R f ): 0.46 (70 % Ethyl acetate in hexane). 4.4.1.4 N-( 2-Methoxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide (46): tert -Butyl 4-(2-((2-methoxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate ( 19 ) (0.75 g, 1.76 mM), through Method C offered the product ( 46 ) (0.53 g, 94.64 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1.5 N-(4-Methoxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide (47): tert -Butyl 4-(2-((4-methoxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate ( 20 ) (0.75 g, 1.76 mM), through Method C offered the product ( 47 ) (0.56 g, 98.24 %). TLC (R f ): 0.42 (70 % Ethyl acetate in hexane). 4.4.1.6 N-(4-Fluorophenyl)-2-phenyl-2-(piperazin-1-yl)acetamide (48): tert -Butyl 4-(2-((4-fluorophenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate ( 21 ) (0.75 g, 1.76 mM), through Method C offered the product ( 48 ) (0.54 g, 94.73 %). TLC (R f ): 0.43 (70 % Ethyl acetate in hexane). 4.4.1.7 N-(4-Chlorophenyl)-2-phenyl-2-(piperazin-1-yl)acetamide (49): tert -Butyl 4-(2-((4-chlorophenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate ( 22 ) (0.75 g, 1.76 mM), through Method C offered the product ( 49 ) (0.55 g, 98.21 %) which was further used for the final reaction. TLC (R f ): 0.47 (70 % Ethyl acetate in hexane). 4.4.1.8 N-(4-Hydroxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide (50): tert -butyl 4-(2-((4-hydroxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate ( 23 ) (0.75 g, 1.76 mM), through Method C offered the product ( 50 ) (0.54 g, 94.73 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1.9 N-Cyclohexyl-2-phenyl-2-(piperazin-1-yl)acetamide (51): tert -butyl 4-(2-(cyclohexylamino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate ( 24 ) (0.75 g, 1.76 mM), through Method C offered the product ( 51 ) (0.55 g, 98.21 %). TLC (R f ): 0.49 (70 % Ethyl acetate in hexane). 4.4.1.10 2-(4-Fluorophenyl)-N-phenyl-2-(piperazin-1-yl)acetamide (52): tert -Butyl 4-(1-(4-fluorophenyl)-2-oxo-2 - (phenylamino)ethyl)piperazine-1-carboxylate ( 25 ) (0.75 g, 1.76 mM through Method C offered the product ( 52 ) (0.54 g, 94.73 %). TLC (R f ): 0.50 (70 % Ethyl acetate in hexane). 4.4.1.11 2-(4-Fluorophenyl)-2-(piperazin-1-yl)-N-(o-tolyl)acetamide (53): tert -Butyl 4-(1-(4-fluorophenyl)-2-oxo-2-( o -tolylamino)ethyl)piperazine-1-carboxylate ( 26 ) (0.75 g, 1.76 mM), through Method C offered the product ( 53 ) (0.53 g, 92.98 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1.12 2-(4-Fluorophenyl)-2-(piperazin-1-yl)-N-(p-tolyl)acetamide (54 ): tert -Butyl 4-(1-(4-fluorophenyl)-2-oxo-2-( p -tolylamino)ethyl)piperazine-1-carboxylate ( 27 ) (0.75 g, 1.76 mM), through Method C offered the product ( 54 ) (0.55 g, 96.49 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1.13 2-(4-Fluorophenyl)-N-(2-methoxyphenyl)-2-(piperazin-1-yl)acetamide (55): tert -Butyl 4-(1-(4-fluorophenyl)-2-((2-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate ( 28 ) (0.75 g, 1.76 mM), through Method C offered the product ( 55 ) (0.56 g, 96.55 %). TLC (R f ): 0.44 (70 % Ethyl acetate in hexane). 4.4.1.14 2-(4-Fluorophenyl)-N-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (56): tert -Butyl 4-(1-(4-fluorophenyl)-2-((4-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate ( 29 ) (0.75 g, 1.76 mM), through Method C offered the product ( 56 ) (0.55 g, 94.82 %). TLC (R f ): 0.44 (70 % Ethyl acetate in hexane). 4.4.1.15 N,2-Bis(4-fluorophenyl)-2-(piperazin-1-yl)acetamide (57): tert -Butyl 4-(1-(4-fluorophenyl)-2-((4-fluorophenyl)amino)-2-oxoethyl)piperazine-1-carboxylate ( 30 ) (0.75 g, 1.76 mM), through Method C offered the product ( 57 ) (0.56 g, 98.24 %). TLC (R f ): 0.45 (70 % Ethyl acetate in hexane). 4.4.1.16 N-(4-Chlorophenyl)-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide (58): tert -Butyl 4-(2-((4-chlorophenyl)amino)-1-(4-fluorophenyl)-2-oxoethyl)piperazine-1-carboxylate ( 31 ) (0.75 g, 1.76 mM), in DCM (7.5 mL), through Method C offered the product ( 58 ) (0.52 g, 89.65 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1.17 2-(4-Fluorophenyl)-N-(4-hydroxyphenyl)-2-(piperazin-1-yl)acetamide (59): tert -Butyl 4-(1-(4-fluorophenyl)-2-((4-hydroxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate ( 32 ) (0.75 g, 1.76 mM), through Method C offered the product ( 59 ) (0.54 g, 94.73 %). TLC (R f ): 0.47 (70 % Ethyl acetate in hexane). 4.4.1.18 N-Cyclohexyl-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide (60): tert -Butyl 4-(2-(cyclohexylamino)-1-(4-fluorophenyl)-2-oxoethyl)piperazine-1-carboxylate ( 33 ) (0.75 g, 1.76 mM), through Method C offered the product ( 60) (0.56 g, 98.24 %). TLC (R f ): 0.52 (70 % Ethyl acetate in hexane). 4.4.1.19 2-(4-Methoxyphenyl)-N-phenyl-2-(piperazin-1-yl)acetamide (61): tert -Butyl 4-(1-(4-methoxyphenyl)-2-oxo-2-(phenylamino)ethyl)piperazine-1-carboxylate ( 34 ) (0.75 g, 1.76 mM), through Method C offered the product ( 61 ) (0.52 g, 94.73%). TLC (R f ): 0.45 (70 % Ethyl acetate in hexane). 4.4.1.20 2-(4-Methoxyphenyl)-2-(piperazin-1-yl)-N-(o-tolyl)acetamide (62): tert -Butyl 4-(1-(4-methoxyphenyl)-2-oxo-2-(o-tolylamino)ethyl)piperazine-1-carboxylate ( 35 ) (0.75 g, 1.76 mM), in DCM (7.5 mL), through Method C offered the product ( 62 ) (0.53 g, 91.37 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1.21 2-(4-Methoxyphenyl)-2-(piperazin-1-yl)-N-(p-tolyl)acetamide (63): tert -Butyl 4-(1-(4-methoxyphenyl)-2-oxo-2-(p-tolylamino)ethyl)piperazine-1-carboxylate ( 36 ) (0.75 g, 1.76 mM), in DCM (7.5 mL), through Method C offered the product ( 63 ) (0.56 g, 96.55 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1.22 N-(2-Methoxyphenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (64): tert -Butyl 4-(1-(4-methoxyphenyl)-2-((2-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate ( 37 ) (0.75 g, 1.76 mM), through Method C offered the product ( 64 ) (0.56 g, 96.55 %) which was further processed for the final reaction. TLC (R f ): 0.42 (70 % Ethyl acetate in hexane). 4.4.1.23 N,2-Bis(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (65): tert -Butyl 4-(1-(4-methoxyphenyl)-2-((4-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate ( 38 ) (0.75 g, 1.76 mM), through Method C offered the product ( 65 ) (0.54 g, 93.10 %). TLC (R f ): 0.42 (70 % Ethyl acetate in hexane). 4.4.1.24 N-(4-Fluorophenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (66): tert -Butyl 4-(2-((4-fluorophenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate ( 39 ) (0.75 g, 1.76 mM), through Method C offered the product ( 66 ) (0.54 g, 96.42 %). TLC (R f ): 0.43 (70 % Ethyl acetate in hexane). 4.4.1.25 N-(4-Chlorophenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (67): tert -Butyl 4-(2-((4-chlorophenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate ( 40 ) (0.75 g, 1.76 mM), through Method C offered the product ( 67 ) (0.57 g, 96.61 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1.26 N-(4-Hydroxyphenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (68): tert -Butyl 4-(2-((4-hydroxyphenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate ( 41 ) (0.75 g, 1.76 mM), through Method C offered the product ( 68 ) (0.52 g, 89.85 %). TLC (R f ): 0.48 (70 % Ethyl acetate in hexane). 4.4.1.27 N-Cyclohexyl-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (69): tert -Butyl 4-(2-(cyclohexylamino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate ( 42 ) (0.75 g, 1.76 mM), through Method C offered the product ( 69 ) (0.56 g, 98.24 %) which was further processed for final reaction. TLC (R f ): 0.36 (70 % Ethyl acetate in hexane). 4.5.1 5-Chloromethylquinolin-8-ol (70): A mixture of 8-hydroxyquinoline (10.0 g, 68 mM), concentrated hydrochloric acid (13 mL) and formalin ( 37 %formaldehyde and 12 % methanol, 12 mL, 399 mM)) was treated with hydrogen chloride gas and stirred for 3 h. The yellow solid obtained was collected on a filter paper, washed three times in acetone, and dried under vacuum to afford 5-chloromethyl-8-hydroxyquinoline ( 70 ) as a yellow solid hydrochloride salt, m.p. >260 o C, Reported >260 o C [42]. 4.6.1 General procedure for the synthesis of the target compounds (71 – 79, 80 – 88 and 89 - 97): (Method D) To a solution of the corresponding products ( 43 - 69 ) (1.0 equiv) in DMSO (7 mL), triethylamine (5.0 equiv) was added and the reaction mixture was stirred at 25 o C for 10 min followed by the addition of 5-chloromethyl-8-hydroxyquinoline hydrochloride ( 70 ) (1.0 equiv) portion-wise. The reaction mixture was stirred at 100 o C for 16 h, and the progress of the reaction was monitored by TLC using (80 % ethyl acetate in hexane) After the consumption of the starting materials, the reaction mixture was poured into ice-cold water to obtain solid products ( 71 - 97 ) which were filtered, dried and further purified by column chromatography using #100-200 silica gel as stationary phase and ethyl acetate:hexane as mobile phase to afford the desired pure products ( 71 - 97 ). 4.6.1.1 2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N,2-diphenylacetamide (71): Using N ,2-diphenyl-2-(piperazin-1-yl)acetamide ( 43 ) (0.5 g, 1.69 mM) and Method D the desired compound ( 71 ) was obtained, m.p. 72-75 °C. TLC (Rf): 0.54 (80 % Ethyl acetate in hexane); IR: 3314, 2931, 2816, 1686, 1599, 1503, 1474, 1440, 1371, 1312, 1271, 1231, 1076, 827 cm -1 ; 1 H NMR: δ 9.25 (s, 1H, N H ), 8.79-8.78 (d, 1H, Ar H ), 8.63-8.61 (d, 1H, Ar H ), 7.61-7.59 (d, 2H, Ar H ), 7.47-7.44 (dd, 1H, Ar H ), 7.38-7.36 (d, 2H, Ar H ), 7.33 (s, 5H, Ar H ), 7.28 (s, 1H, Ar H ), 7.15-7.11 (t, 1H, Ar H ), 7.08-7.06 (d, 1H, Ar H ), 3.98 (s, 1H, C H ), 3.83 (s, 2H, C H 2 ), 2.63-2.50 (m, 8H, C H 2 ); C 28 H 28 N 4 O 2 requires: C, 74.31; H, 6.24; N, 12.38; found C, 74.58; H, 6.41; N, 12.10; LC-MS (m/z): 453.2 (M+1); Purity 98.20 %. 4.6.1.2 2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl-N-(o-tolyl)acetamide (72): Using 2-phenyl-2-(piperazin-1-yl)-N-(o-tolyl)acetamide ( 44 ) (0.5 g, 1.61 mM) and Method D the desired compound ( 72 ) was obtained as a yellowish white solid (0.59 g, 78.66 %), which was further purified by column chromatography using #100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 110-112 °C. TLC (R f ): 0.52 (80 % Ethyl acetate in hexane); IR: 3338, 2923, 2812, 2766, 1669, 1596, 1505, 1475, 1229, 1136, 1007, 699 cm -1 ; 1 H NMR; δ 9.71-9.61 (m, 2H, N H, O H ), 8.85-8.79 (d, 1H, Ar H ), 8.64-8.52 (d, 1H, Ar H ), 7.57-6.98 (m, 11H, Ar H ), 4.09 (s, 1H, Ar H ), 3.78 (s, 2H, Ar H ), 2.69- 2.56 (bs, 3H, C H 2 ), 2.41-2.35 (bs, 5H, C H 2 ), 2.18 (s, 3H, C H 3 ); C 29 H 30 N 4 O 2 requires: C, 74.65; H, 6.48; N, 12.01; found C, 74.44; H, 6.56; N, 11.83; Mass (m/z): 467.4 (M+1). 4.6.1.3 2-(4-((8- Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl-N-(p-tolyl)acetamide (73): Using 2-phenyl-2-(piperazin-1-yl)- N -( p -tolyl)acetamide ( 45 ) (0.5 g, 1.61 mM) and Method D the desired compound ( 73 ) was obtained as a greenish white solid (0.57 g, 76 %), which was further purified by column chromatography using #100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 165-168 °C. TLC (R f ): 0.53 (80 % Ethyl acetate in hexane); IR: 3329, 2817, 1658, 1595, 1472, 1363, 1230, 1133, 1004, 705 cm -1 ; 1 H NMR: δ 9.16 (s, 1H, N H ), 8.79-8.78 (d, 1H, Ar H ), 8.63-8.61 (d, 1H, Ar H ), 7.49-7.44 (m, 3H, Ar H ), 7.34-7.32 (d, 6H, Ar H ), 7.17-7.14 (d, 2H, Ar H ), 7.08-7.06 (d, 1H, Ar H ), 3.97 (s, 1H, C H ), 3.84 (s, 2H, C H 2 ), 2.53 (d , 8H, C H 2 ), 2.34 (s, 3H, C H 3 ); C 29 H 30 N 4 O 2 requires: C, 74.65; H, 6.48; N, 12.01; found C, 74.48; H, 6.65; N, 12.22; LC-MS (m/z): 467.5 (M+1); Purity 95.58 %. 4.6.1.4 2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(2-methoxyphenyl)-2-phenyl- acetamide (74): Using N -(2-methoxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide ( 46 ) (0.5 g, 1.53 mM) and Method D the desired compound ( 74 ) was obtained as a light orange solid (0.57 g, 76 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 82-85 °C. TLC (R f ): 0.49 (80 % Ethyl acetate in hexane); IR: 3327, 2936, 2814, 1738, 1598, 1521, 1460, 1230, 1025, 787 cm -1 ; 1 H NMR: δ 9.97 (s, 1H, N H ), 9.72 (s, 1H, O H ), 8.83-8.82 (d, 1H, Ar H ), 8.60-8.58 (d, 2H, Ar H ), 8.11- 8.09 (d, 1H, Ar H ), 7.56-7.53 (dd, 1H, Ar H ), 7.34 (d, 4H, Ar H ), 7.28(d, 2H, Ar H ), 7.08-7.07 (d, 2H, Ar H ), 6.99-6.97 (d, 1H, Ar H ), 6.92-6.84 (m, 1H, Ar H ), 4.21 (s, 1H, C H ), 3.94 (s, 3H, C H 2 ), 3.79-3.34 (m, 2H, OC H 3 ), 2.47-2.20 (m, 8H, C H 2 ); C 29 H 30 N 4 O 3 requires: C, 72.18; H, 6.27; N, 11.61; found C, 71.81; H, 6.54; N, 11.43; Mass (m/z): 483.3 (M+1). 4.6.1.5 2-(4-(( 8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(4-methoxyphenyl)-2-phenyl- acetamide (75): Using N -(4-methoxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide ( 47 ) (0.5 g, 1.53 mM) and Method D the desired compound ( 75 ) was obtained as a yellowish white solid (0.57 g, 77 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 175-178 °C. TLC (R f ): 0.49 (80 % Ethyl acetate in hexane); IR: 3332, 2955, 2808, 1664, 1520, 1473, 1248, 1135, 1030, 821 cm -1 ; 1 H NMR; δ 9.92 (s, 1H, N H ), 9.72 (s, 1H, O H ), 8.85 (d, 1H, Ar H ), 8.63-8.61 (d, 1H, Ar H ), 7.59-7.57 (dd, 1H, Ar H ), 7.51-7.46 (m, 4H, Ar H ), 7.36-7.26 (m, 4H, Ar H ), 6.99-6.97 (d, 1H, Ar H ), 6.88-8.84 (d, 2H, Ar H ), 3.94 (s, 1H, C H ), 3.78 (s, 2H, C H 2 ), 3.70 (s, 3H, OC H 3 ), 2.35 (bs, 8H, C H 2 ); C 29 H 30 N 4 O 3 requires: C, 72.18; H, 6.27; N, 11.61; found C, 71.88; H, 6.55; N, 11.31; Mass (m/z): 483.3 (M+1). 4.6.1.6 N-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl- acetamide (76): Using N -(4-fluorophenyl)-2-phenyl-2-(piperazin-1-yl)acetamide ( 48 ) (0.5 g, 1.59 mM) and Method D the desired compound ( 76 ) was obtained as a yellowish white solid (0.58 g, 77.33 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 89-90°C. TLC (R f ): 0.51 (80 % Ethyl acetate in hexane); IR: 3296, 2822, 1669, 1509, 1406, 1372, 1211, 1006, 835 cm -1 ; 1 H NMR: δ 10.22- 10.11 (d, 1H, N H ), 9.71 (bs, 1H, O H ), 8.86-8.85 (d, 1H, Ar H ), 8.64-8.62 (d, 1H, Ar H ), 7.77- 7.59 (m, 2H, Ar H ), 7.50-7.48 (m, 2H, Ar H ), 7.37-7.36 (m, 4H, Ar H ), 7.15-7.13 (d, 2H, Ar H ), 7.01-6.99 (d, 1H, Ar H ), 3.80 (s, 1H, C H ), 3.41 (s, 2H, C H 2 ), 2.69 (s, 2H, C H 2 ), 2.43- 2.47 (d, 4H, C H 2 ); C 28 H 27 FN 4 O 2 requires: C, 71.47; H, 5.78; N, 11.91; found C, 71.16; H, 5.96; N, 11.72; Mass (m/z): 471.3 (M+1). 4.6.1.7 N-(4-Chlorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl- acetamide (77): Using N -(4-chlorophenyl)-2-phenyl-2-(piperazin-1-yl)acetamide ( 49 ) (0.5 g, 1.51 mM) and Method D the desired compound ( 77 ) was obtained as a yellowish white solid (0.58 g, 77.33 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 89-90°C. TLC (R f ): 0.51 (80 % Ethyl acetate in hexane); IR: 3296, 2822, 1669, 1509, 1406, 1372, 1211, 1006, 835 cm -1 ; 1 H NMR: δ 10.22- 10.11 (d, 1H, N H ), 9.71 (bs, 1H, O H ), 8.86-8.85 (d, 1H, Ar H ), 8.64-8.62 (d, 1H, Ar H ), 7.77- 7.59 (m, 2H, Ar H ), 7.50-7.48 (m, 2H, Ar H ), 7.37-7.36 (m, 4H, Ar H ), 7.15-7.13 (d, 2H, Ar H ), 7.01-6.99 (d, 1H, Ar H ), 3.80 (s, 1H, C H ), 3.41 (s, 2H, C H 2 ), 2.69 (s, 2H, C H 2 ), 2.43- 2.47 (d, 4H, C H 2 ); C 28 H 27 ClN 4 O 2 requires: C, 69.06; H, 5.59; N, 11.50; found C, 68.78; H, 5.87; N, 11.34; Mass (m/z): 471.3 (M+1). 4.6.1.8 N-(4-Hydroxyphenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl- acetamide (78): Using N -(4-hydroxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide ( 50 ) (0.5 g, 1.44 mM) and Method D the desired compound ( 78 ) was obtained as a brown solid (0.59 g, 79.72 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 155-158 °C. TLC (R f ): 0.52 (80 % Ethyl acetate in hexane); IR: 3331, 2928, 2813, 1677, 1592, 1474, 1398, 1270, 1134, 1005 cm -1 ; 1 H NMR: δ 10.19 (s, 1H, N H ), 9.71 (s, 1H, O H ), 8.85- 8.84 (d, 1H, Ar H ), 8.63-8.64 (d, 1H, Ar H ), 7.65-7.63 (d, 2H, Ar H ), 7.57-7.56 (d, 1H, Ar H ), 7.49-7.47 (d, 2H, Ar H ), 7.37-7.32 (m, 6H, Ar H ), 7.0-6.99 (d, 1H, Ar H ), 3.99 (s, 1H, C H ), 3.78 (s, 2H, C H 2 ), 2.47-2.36 (bs, 8H, C H 2 ); C 28 H 28 N 4 O 3 requires: C, 71.78; H, 6.02; N, 11.96; found C, 71.56; H, 6.35; N, 11.74; Mass (m/z): 487.3 (M + ). 488.3 (M+1), 489.2 (M+2). 4.6.1. 9 N-Cyclohexyl-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenylacetamide (79): Using N -cyclohexyl-2-phenyl-2-(piperazin-1-yl)acetamide ( 51 ) (0.5 g, 1.44 mM) and Method D the desired compound ( 79 ) was obtained as a greenish-white solid (0.63 g, 82.89 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. >220 °C. TLC (R f ): 0.43 (80 % Ethyl acetate in hexane); IR: 3320, 2924, 2818, 1662, 1514, 1474, 1371, 1231, 1004 cm -1 ; 1 H NMR: δ 9.79 (s, 1H, O H ), 9.71 (s, 1H, O H ), 9.20 (s, 1H, N H ), 8.87-8.84 (d, 1H, Ar H ), 8.63-8.57 (d, 1H, Ar H ), 7.58-7.55 (m, 1H, Ar H ), 7.45-7.46 (d, 2H, Ar H ), 7.36-7.25 (m, 6H, Ar H ), 6.99-6.97 (d, 1H, Ar H ), 6.67-6.65 (d, 2H, Ar H ), 3.91 (s, 1H), 3.76 (s, 2H, C H 2 ), 2.54 (s, 1H, C H ), 2.50-2.33 (ds, 7H, C H 2 ); 13 C NMR δ: 169.01, 147.66, 138.80, 137.52, 133.72, 128.78, 128.51, 128.00, 127,80, 127.44, 121.32, 109.87, 74.12, 59.53, 52.55, 50.67, 47.15, 40.41, 32.32, 32.04, 25.11, 24.43. C 28 H 34 N 4 O 2 requires: C, 73.33; H, 7.47; N, 12.22; found C, 73.05; H, 7.78; N, 12.04; Mass (m/z): 469.3 (M+1). 4.6.1.10 2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-phenyl- acetamide (80): Using 2-(4-fluorophenyl)- N -phenyl-2-(piperazin-1-yl)acetamide ( 52 ) (0.5 g, 1.59 mM) and Method D the desired compound ( 80 ) was obtained as a greenish white solid (0.56 g, 74.66 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 74-77 °C, TLC (R f ): 0.48 (80 % Ethyl acetate in hexane), IR: 3305, 3056, 2931, 2815, 1685, 1507, 1439, 1353, 1246, 1176, 1133, 1030 cm -1 ; 1 H NMR: δ 10.08 (s, 1H, N H ), 9.72 (s, 1H, O H ), 8.84 (d, 1H, Ar H ), 8.62 (d, 1H, Ar H ), 7.60-7.57 (m, 3H, Ar H ), 7.55-7.53 (m, 2H, Ar H ), 7.35-7.24 (m, 3H, Ar H ), 7.18 (t, 2H, Ar H ), 7.05 (t, 1H, Ar H ), 6.98 (d, 1H, Ar H ), 4.02 (s, 1H, C H ), 3.78 (s, 2H, C H 2 ), 2.55-2.25 (m, 8H, C H 2 ); 13 C NMR δ: 168.95, 162.92, 160.50, 152.75, 147.69, 138.78, 133.66, 133.19, 130.55, 128.75, 127.79, 123.97, 123.58, 121.33, 119.53, 115.15, 114.94, 109.88, 73.69, 59.48, 52.48, 50.63. C 28 H 27 FN 4 O 2 requires: C, 71.47; H, 5.78; N, 11.91; found C, 71.15; H, 5.95; N, 11.73; Mass (m/z): 471.3 (M+1). 4.6.1.11 2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(o-tolyl)- acetamide (81): Using 2-(4-fluorophenyl)-2-(piperazin-1-yl)- N -( o -tolyl)acetamide ( 53 ) (0.5 g, 1.53 mM) and Method D the desired compound ( 81 ) was obtained as a greenish-white solid (0.57 g, 77 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 86-89 °C. TLC (Rf): 0.51 (80 % Ethyl acetate in hexane); IR: 3312, 2931, 1675, 1508, 1439, 1350, 1245, 1133, 1028 cm -1 ; 1H NMR: δ 9.70 (s, 1H, O H ), 9.61 (s, 1H, N H ), 8.85-8.83 (dd, 1H, Ar H ), 8.63-8.60 (d, 1H, Ar H ), 7.58-7.55 (m, 1H, Ar H ), 7.49-7.46 (m, 4H, Ar H ), 7.34-7.32 (d, 1H, Ar H ), 7.21-7.19 (m, 3H, Ar H ), 7.17 (s, 1H, Ar H ), 7.15-7.13 (d, 1H, Ar H ), 7.09-7.05 (m, 2H, Ar H ), 6.99-6.97 (d, 1H, C H 2 ), 4.12(s, 1H, C H ), 3.81-3.74 (m, 3H, C H 3 ), 2.51-2.38 (bs, 4H, C H 2 ), 2.16 (s, 4H, C H 2 ); C 29 H 29 FN 4 O 2 requires: C, 71.88; H, 6.03; N, 11.56; found C, 71.55; H, 6.46; N, 11.27; Mass (m/z): 485.4 (M+1). 4.6.1. 12 2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(p-tolyl)- acetamide (82): Using 2-(4-fluorophenyl)-2-(piperazin-1-yl)- N -( p -tolyl)acetamide ( 54 ) (0.5 g, 1.53 mM) and Method D the desired compound ( 82 ) was obtained as a yellowish white solid (0.58 g, 78.37 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 103-106 °C. TLC (R f ): 0.53 (80 % Ethyl acetate in hexane); IR: 3314, 2924, 2816, 1689, 1599, 1507, 1461, 1432, 1225 1115, 788, 749 cm -1 ; 1 H NMR δ 9.96 (s, 1H, N H ), 9.67 (s, 1H, O H ), 8.85-8.84 (dd, 1H, Ar H ), 8.64-8.61 (dd, 1H, Ar H ), 7.58- 7.55 (m, 1H, Ar H ), 7.52-7.48 (m, 2H, Ar H ), 7.47- 7.45 (d, 2H, Ar H ), 7.33-7.32 (d, 1H, Ar H ), 7.20-7.15 (t, 2H, Ar H ), 7.10-7.08 (d, 2H, Ar H ), 7.00-6.98 (d, 1H, Ar H ), 4.00 (s, 1H, C H ), 3.78 (s, 2H, C H 2 ), 2.54-2.35 (bs, 8H, C H 2 ), 2.24 (s, 3H, C H 3 ); C 29 H 29 FN 4 O 2 requires; C, 71.88; H, 6.03; N, 11.56; found C, 71.76; H, 6.37; N, 11.23; Mass (m/z): 485.3 (M+1). 4.6.1.13 2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(2-methoxyphenyl)acetamide (83): Using 2-(4-fluorophenyl)- N -(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide ( 55 ) (0.5 g, 1.45 mM) and Method D the desired compound ( 83 ) was obtained as a yellowish white solid (0.56 g, 76.71 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p.140-143 °C. TLC (R f ): 0.51 (80 % Ethyl acetate in hexane); IR: 3312, 2927, 2816, 1691, 1599, 1523, 1506, 1477, 1461, 1225, 1169, 1026, 789, 750 cm -1 ; 1 H NMR: δ 9.97 (s, 1H, NH), 9.69 (s, 1H, OH), 8.84-8.83 (dd, 1H, Ar H ), 8.61-8.59 (dd, 1H, Ar H ), 8.10-8.08 (m, 1H, Ar H ), 7.57-7.54 (dd, 1H, Ar H ), 7.35-7.32 (t, 3H, Ar H ), 7.21-7.16 (t, 2H, Ar H ), 7.10-7.08 (m, 2H, Ar H ), 7.00-6.98 (d, 1H, Ar H ), 6.94-6.90 (m, 1H, Ar H ), 4.30 (s, 1H, C H ), 3.94 (s, 3H, OC H 3 ), 3.80 (s, 2H, C H 2 ), 2.68 (bs, 4H, C H 2 ), 2.37 (bs, 4H, C H 2 ); C 29 H 29 FN 4 O 3 requires: C, 69.58; H, 5.84; F, 3.80; N, 11.19; found C, 69.36; H, 6.16; N, 10.91; LC-MS (m/z): 501.5 (M+1); Purity 97.11 %. 4.6.1.14 2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(4-methoxyphenyl)acetamide (84): Using N ,2-bis(4-fluorophenyl)-2-(piperazin-1-yl)acetamide ( 56 ) (0.5 g, 1.45 mM) and Method D the desired compound (84) was obtained as a yellowish white solid (0.54 g, 73.93 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 86-88 °C. TLC (R f ): 0.52 (80 % Ethyl acetate in hexane); IR: 3312, 2933, 2817, 1682, 1603, 1509, 1474, 1412, 1230, 1371, 1133, 1033, 1005, 828, 787 cm -1 ; 1 H NMR: δ 9.92 (s, 1H, NH), 9.67 (s, 1H, O H ), 8.85-8.84 (d, 1H, Ar H ), 8.64-8.61 (d, 1H, Ar H ), 7.59-7.55 (dd, 1H, Ar H ), 7.52-7.48 (m, 4H, Ar H ), 7.34-7.32 (d, 1H, Ar H ), 7.20-7.15 (t, 2H, Ar H ), 7.0-6.98 (d, 1H, Ar H ), 6.88-6.85 (m, 2H, Ar H ), 3.97 (s, 1H, C H ), 3.78 (s, 2H, C H 2 ), 3.71 (s, 3H, OC H 3 ), 2.69 (d, 4H, C H 2 ), 2.34 (s, 4H, C H 2 ); C 29 H 29 FN 4 O 3 requires: C, 69.58; H, 5.84; N, 11.19; found C, 69.35; H, 5.96; N, 11.02; LC-MS (m/z): 501.4 (M+1); Purity 94.50 %. 4.6.1.15 N,2-bis(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)- acetamide (85): Using N -(4-chlorophenyl)-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide ( 57 ) (0.5 g, 1.50 mM) and Method D the desired compound ( 85 ) was obtained as a greenish white solid (0.57 g, 79.16 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 85-88 °C. TLC (R f ): 0.48 (80 % Ethyl acetate in hexane); IR: 3391, 2923, 1693, 1507, 1474, 1271, 1227, 1005 cm -1 ; 1 H NMR: δ 10.12 (s, 1H, N H ), 9.68 (s, 1H, O H ), 8.85-8.84 (d, 1H, Ar H ), 8.63-8.61 (dd, 1H, Ar H ), 7.63-7.59 (m, 2H, Ar H ), 7.57 (m, 1H, Ar H ), 7.53-7.49 (m, 2H, Ar H ), 7.33-7.31 (d, 1H, Ar H ), 7.20-7.16 (m, 2H, Ar H ),7.15-7.10 (m, 2H, Ar H ) 7.00-6.98 (d, 1H, Ar H ), 4.00 (s, 1H, C H ), 3.78 (s, 2H, C H 2 ), 2.47- 2.33 (bs, 8H, C H 2 ); C 28 H 26 F2N 4 O 2 requires: C, 68.84; H, 5.36; F, 7.78; N, 11.47; found C, 68.68; H, 5.57; N, 11.15; LC-MS (m/z): 489.4 (M+1); Purity 98.68 %. 4.6.1.16 N-(4-Chlorophenyl)-2-(4-fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)- piperazin-1-yl)acetamide (86) : Using N -(4-chlorophenyl)-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide ( 58 ) (0.5 g, 1.45 mM) and Method D the desired compound ( 73 ) was obtained as a greenish white solid (0.57 g, 79.16 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 80-83 °C. TLC (R f ): 0.46 (80 % Ethyl acetate in hexane); IR: 3314, 2924, 2819, 1693, 1598, 1505, 1399, 1271, 1228, 1006, 828 cm -1 ; 1H NMR: δ 10.21 (s, 1H, N H ), 8.85-8.83 (d, 1H, Ar H ), 8.64-8.61 (d, 1H, Ar H ), 7.66-7.62 (m, 2H, Ar H ), 7.59-7.56 (dd, 1H, Ar H ), 7.53-7.49 (m, 2H, Ar H ), 7.36-7.32 (m, 3H, Ar H ), 7.21-7.16 (m, 2H, Ar H ), 7.00-6.99 (d, 1H, Ar H ), 4.02 (s, 1H, C H ), 3.78 (s, 2H, C H 2 ), 2.71-2.34 (bm, 8H, C H 2 ); C 28 H 26 ClFN 4 O 2 requires: C, 66.60; H, 5.19; N, 11.09; found C, 66.98; H, 5.49; N, 10.87; Mass (m/z): 505.3 (M+), 507.2 (M+2). 4.6.1.17 2-(4-Fluorophenyl)-N-(4-hydroxyphenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)- piperazin-1-yl)acetamide (87): Using 2-(4-fluorophenyl)- N -(4-hydroxyphenyl)-2-(piperazin-1-yl)acetamide ( 59 ) (0.5 g, 1.52 mM) and Method D the desired compound ( 87 ) was obtained as a obtain brown solid (0.56 g, 75.67 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 80-82 °C. TLC (R f ): 0.40 (80 % Ethyl acetate in hexane); IR: 3270, 2923, 2816, 1664, 1506, 1474, 1226, 1016, 832 cm -1 ; 1 H NMR: δ 9.81 (s, 1H, N H ), 9.68 (s, 1H, O H ), 9.19 (s, 1H, O H ), 8.85-8.84 (d, 1H, Ar H ), 8.63-8.61 (d, 1H, Ar H ), 7.59-7.55 (m, 1H, Ar H ), 7.51-7.48 (m, 2H, Ar H ), 7.36-7.31 (t, 3H, Ar H ), 7.19-7.15 (t, 2H, Ar H ), 6.99-6.98 (d, 1H, Ar H ), 6.68-6.65 (d, 2H, Ar H ), 3.95 (s, 1H, C H ), 3.78 (s, 2H, C H 2 ), 2.68 (s, 4H, C H 2 ), 2.33 (s, 4H, C H 2 ); C 28 H 27 FN 4 O 3 requires: C, 69.12; H, 5.59; N, 11.52; found C, 69.43; H, 5.87; N, 11.34; LCMS (m/z): 487.4 (M+1); Purity 98.85 %. 4.6.1. 18 N-Cyclohexyl-2-(4-fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)acetamide (88): Using N -cyclohexyl-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide ( 60 ) (0.5 g, 1.56 mM) and Method D the desired compound ( 88 ) was obtained as a yellowish white solid (0.61 g, 82.43 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 195-196 °C. TLC (R f ): 0.46 (80 % Ethyl acetate in hexane); IR: 3322, 2928, 2850, 1649, 1502, 1473, 1270, 1223, 1004, 829, 701 cm -1 ; 1 H NMR: δ 9.71 (s, 1H, N H ), 8.85-8,83 (dd, 1H, Ar H ), 8.62-8.59 (d, 1H, Ar H ), 7.86-7.85 (d, 1H, Ar H ), 7.57-7.54 (q, 1H, Ar H ), 7.41-7.38 (m, 2H, Ar H ), 7.32-7.30 (d, 1H, Ar H ), 7.15-7.11(d, 2H, Ar H ), 6.99-6.97 (d, 1H, Ar H ), 3.77-3.75 (d, 3H, C H 2, C H ), 3.49-3.47 (d, 1H, C H ), 2.41 (bs, 4H, C H 2 ), 2.26 (bs, 3H, C H 2 ), 1.69-1.51 (m, 5H, C H 2 ), 1.22-1.09 (m, 5H, C H 2 ); C 28 H 33 FN 4 O 2 requires: C, 70.56; H, 6.98; N, 11.76; found C, 70.38; H, 7.17; N, 11.48; Mass (m/z): 477.4 (M+1). 4.6.1.19 2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)-N-phenyl- acetamide (89): Using 2-(4-methoxyphenyl)- N -phenyl-2-(piperazin-1-yl)acetamide ( 61 ) (0.5 g, 1.54 mM) and Method D the desired compound ( 89 ) was obtained as a white solid (0.56 g, 75.67 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 96-99 °C; TLC (R f ): 0.56 (80 % Ethyl acetate in hexane); IR: 3305, 3056, 2931, 2815, 1685, 1507, 1439, 1246, 1176, 1133, 1030 cm -1 ; 1 H NMR: δ 9.97 (s, 1H, N H ), 9.72 (s, 1H, O H ), 8.84-8.83 (d, 1H, Ar H ), 8.86-8.60 (d, 1H, Ar H ), 7.59-7.55 (m, 3H, Ar H ), 7.39-7.37 (d, 2H, Ar H ), 7.32-7.25 (m, 3H, Ar H ), 7.04-7.01 (t, 1H, Ar H ), 6.98-6.96 (d, 1H, Ar H ), 6.91-6.88 (d, 2H, Ar H ), 3.90 (s, 1H, CH), 3.76 (s, 2H, C H 2 ), 3.72 (s, 3H, OC H 3 ), 2.67 (s, 4H, C H 2 ), 2.33 (s, 4H, C H 2 ); C 29 H 30 N 4 O 3 requires: C, 72.18; H, 6.27; N, 11.61; found C, 72.06; H, 6.49; N, 11.49; Mass (m/z): 483.3 (M+1). 4.6.1. 20 2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)-N-(o-tolyl) acetamide (90): Using 2-(4-methoxyphenyl)-2-(piperazin-1-yl)- N -( o -tolyl)acetamide ( 62 ) (0.5 g, 1.47 mM) and Method D the desired compound ( 90 ) was obtained as a greenish white solid (0.58 g, 79.45 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 86-88 °C. TLC (R f ): 0.62 (80 % Ethyl acetate in hexane); IR: 3332, 2922, 2833, 1689, 1608, 1582, 1505, 1229, 786 cm -1 ; 1 H NMR: δ 9.70 (d, 1H, N H ), 9.54 (d, 1H, O H ), 8.90-8.78 (m, 2H, Ar H ), 8.65-8.33 (m, 2H, Ar H ), 7.62-7.48 (m, 2H, Ar H ), 7.37-7.28 (m, 2H, Ar H ), 7.25-7.04 (m, 2H , Ar H ), 6.97 (d, 2H, Ar H ), 6.87 (d, 1H, Ar H ), 4.80-4.27 (m, 2H, C H 2 ), 3.97 (d, 1H, C H ), 3.81-3.69 (m, 3H, OC H 3 ), 2.37 (bs, 4H, C H 2 ), 2.18 (bs, 3H, C H 3 ); 13 C NMR δ: 169.21, 158.81, 152.79, 151.90, 147.72, 138.83, 135.96, 133.70, 132.86, 130.23, 128.77, 127.77, 126.67, 126.08, 124.76, 123.28, 121.41, 113.59, 110.58, 109.88, 73.99, 59.53, 54.98, 52.67, 17.60. C 30 H 32 N 4 O 3 requires: C, 72.56; H, 6.50; N, 11.28; found C, 72.75; H, 6.82; N, 11.06; Mass (m/z): 497.4 (M+1). 4.6.1.21 2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)-N-(p-tolyl) acetamide (91): Using 2-(4-methoxyphenyl)-2-(piperazin-1-yl)- N -( p -tolyl)acetamide ( 63 ) (0.5 g, 1.47 mM) and Method D the desired compound ( 91 ) was obtained as a white solid (0.51 g, 69.86 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 103-105 °C. TLC (R f ): 0.48 (80 % Ethyl acetate in hexane); IR: 3327, 3037, 2921, 1686, 1580, 1506, 1473, 1418, 1370, 1274, 1224, 1192, 1251, 781 cm -1 ; 1 H NMR: δ 9.69 (s, 2H, N H, O H ), 8.87-8.88 (d, 2H, Ar H ), 8.47-8.45 (d, 2H, Ar H ), 7.66-7.37 (m, 3H, Ar H ), 7.07-6.90 (m, 5H, Ar H ), 4.68 (s, 2H, C H 2 ), 3.88-3.72 (m, 1H, C H ), 3.36 (s, 3H, OC H 3 ), 2.57 (dd, 3H, C H 3 ), 2.34-2.14 (m, 4H, C H 2 ); C 30 H 32 N 4 O 3 requires: C, 72.56; H, 6.50; N, 11.28; found C, 72.74; H, 6.73; N, 11.06; Mass (m/z): 497.4 (M+1). 4.6.1.22 2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(2-methoxyphenyl)-2-(4-methoxyphenyl)acetamide (92): Using N -(2-methoxyphenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide ( 64 ) ( 0.5 g, 1.40 mM) and Method D the desired compound ( 92 ) was obtained as a yellowish white solid (0.58 g, 80.55 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 153-155 °C. TLC (R f ): 0.46 (80 % Ethyl acetate in hexane); IR: 3314, 2927, 2832, 1689, 1599, 1460, 1371, 1248, 1115, 1028 cm -1 ; 1 H NMR: δ 9.95 (s, 1H, N H ), 9.71 (s, 1H, O H ), 8.85-8.83 (d, 1H, Ar H ), 8.61-8.60 (d, 1H, Ar H ), 8.11-8.09 (s, 1H, Ar H ), 7.58-7.54 (m, 1H, Ar H ), 7.36-7.34 (d, 1H, Ar H ), 7.22-7.20 (d, 2H, Ar H ), 7.11-7.07 (d, 2H, Ar H ), 7.01-6.99 (d, 1H, Ar H ), 6.94-6.90 (m, 3H, Ar H ), 4.13 (s, 1H, C H ), 3.95 (s, 3H, OC H 3 ), 3.84-3.79 (d, 2H, C H 2 ), 3.76 (s, 3H, OC H 3 ), 2.35 (s, 9H, C H 2 ); C 30 H 32 N 4 O 4 requires: C, 70.29; H, 6.29; N, 10.93; found C, 70.08; H, 6.47; N, 10.76; Mass (m/z): 513.3 (M+1). 4.6.1.23 2-(4-(( 8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N,2-bis(4-methoxyphenyl)- acetamide (93) : Using N ,2-bis(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide ( 65 ) (0.5 g, 1.40 mM) and Method D the desired compound ( 93 ) was obtained as a yellowish white solid (0.60 g, 83.33 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 145-147°C. TLC (R f ): 0.49 (80 % Ethyl acetate in hexane); IR: 3307, 2822, 1664, 1508, 1468, 1232, 1175, 1133, 1029 cm -1 ; 1 H NMR: δ 9.84 (s, 1H, N H ), 9.69 (s, 1H, O H ), 8.85-8.83 (dd, 1H, Ar H ), 8.63-8.60 (dd, 1H, Ar H ), 7.58-7.55 (m, J = 4.5 Hz, 1H, Ar H ), 7.50-7.47 (d, 2H, Ar H ), 7.38-7.36 (d, 2H, Ar H ), 7.33-7.31 (d,1H, Ar H ), 6.99-6.97 (d, 1H, Ar H ), 6.90-6.83 (m, 4H, Ar H ), 3.86 (s, 1H, C H ), 3.77 (s, 2H, C H 2 ), 3.72 (s, 3H, OC H 3 ), 3.70 (s, 3H, OC H 3 ), 2.51-2.38 (s, 8H, C H 2 ); C 30 H 32 N 4 O 4 requires: C, 70.29; H, 6.29; N, 10.93; found C, 69.95; H, 6.61; N, 10.76; Mass (m/z): 513.3 (M+1). 4.6.1.24 N -(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetamide (94) : Using N -(4-fluorophenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide ( 66 ) (0.5 g, 1.45 mM) and Method D the desired compound ( 94 ) was obtained as a yellowish white solid (0.57 g, 78 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 160-163°C. TLC (R f ): 0.51 (80 % Ethyl acetate in hexane); IR:3294, 3002, 2937, 2817, 1689, 1610, 1508, 1371, 1301, 1247, 1135, 1007, 832 cm -1 ; 1 H NMR: δ 10.04 (s, 1H, N H ), 9.71 (s, 1H, O H ), 8.84-8.83 (d, 1H, Ar H ), 8.62-8.60 (d, 1H, Ar H ), 7.62-7.55 (m, 3H, Ar H ), 7.42-7.30 (dd, 3H, Ar H ), 7.13-7.09 (t, 2H, Ar H ), 6.99-6.88 (dd, 3H, Ar H ), 3.87 (s, 1H, C H ), 3.76 (s, 2H, C H 2 ), 3.72 (s, 3H, OC H 3 ), 2.45-2.33 (bs, 7H); C 29 H 29 FN 4 O 3 requires: C, 69.58; H, 5.84; N, 11.19; found C, 69.34; H, 5.95; N, 11.06; Mass (m/z): 501.3 (M + ). 4.6.1.25 N-(4-Chlorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetamide (95): Using of N -(4-chlorophenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide ( 67 ) (0.5 g, 1.38 mM) and Method D the desired compound ( 95 ) was obtained as a green solid (0.56 g, 77.77 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 135-138 °C. TLC (R f ): 0.52 (80 % Ethyl acetate in hexane); IR: 3316, 2817, 1692, 1583, 1504, 1473, 1372, 1232, 1177, 1005, 787 cm -1 ; 1 H NMR: δ 10.12 (s, 1H, N H ), 9.71 (s, 1H, O H ), 8.88-8.84 (m, 1H, Ar H ), 8.63-8.61 (m, 1H, Ar H ), 7.65-7.63 (d, 2H, Ar H ), 7.59-7.56 (dd, 1H, Ar H ), 7.40-7.32 (m, 5H, Ar H ), 6.99-6.98 (d, 1H, Ar H ), 6.92-6.90 (d, 2H, Ar H ), 3.91 (s, 1H, C H ), 3.78 (s, 2H, C H 2 ), 3.73 (s, 3H, OC H 3 ), 2.46-2.35 (d, 8H, C H 2 ); C 29 H 29 ClN 4 O 3 requires: C, 67.37; H, 5.65; N, 10.84; found C, 67.61; H, 5.98; N, 10.62; Mass (m/z): 517.3 (M + ), 519.1 (M+2). 4.6.1.26 N-(4-Hydroxyphenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetamide (96): Using N -(4-hydroxyphenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide ( 68 ) (0.5 g, 1.46 mM) and Method D the desired compound ( 96 ) was obtained as an orange solid (0.54 g, 73.97 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 170-172 °C. TLC (R f ): 0.38 (80 % Ethyl acetate in hexane); IR: 3317, 2948, 2820, 1659, 1607, 1510, 1476, 1371, 1233, 1180, 1032 cm -1 ; 1 H NMR: δ 10.06 (bs, 1H, O H ), 9.73 (s, 1H, N H ), 9.20 (s, 1H, O H ), 8.90-8.84 (dd, 1H, Ar H ), 8.65-8.61 (t, 1H, Ar H ), 8.01-7.85 (dd, 1H, Ar H ), 7.71-7.66 (m, 2H, Ar H ), 7.58-7.55 (m, 1H, Ar H ), 7.45-7.41 (m, 1H, Ar H ), 7.38-7.31 (m, 3H, Ar H ), 7.10-6.97 (dd, 1H, Ar H ), 6.90-6.88 (d, 1H, Ar H ), 6.67-6.65 (d, 1H, Ar H ), 3.85 (s, 1H, C H ), 3.78 (s, 2H, C H 2 , ), 3.73 (s, 3H, OC H 3 ), 2.34 (bs, 8H, C H 2 ); C 29 H 30 N 4 O 4 requires: C, 69.86; H, 6.07; N, 11.24; found C, 69.69; H, 6.25; N, 11.15; Mass (m/z): 499.3 (M+1). 4.6.1.27 N-(4-Hydroxyphenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetamide (97): Using N -cyclohexyl-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (69) (0.5 g, 1.50 mM) and Method D the desired compound ( 97 ) was obtained as a white solid (0.63 g, 85.13 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate:Hexane as mobile phase, m.p. 197-199 °C. TLC (R f ): 0.52 (80 % Ethyl acetate in hexane); IR: 3325, 2934, 2852, 2817, 1644, 1509, 1475, 1376, 1246, 1180, 1135, 1006 cm -1 ; 1 H NMR: δ 9.91 (s, 1H, N H ), 8.84 (s, 1H, O H ), 8.61-8.58 (d, 1H, Ar H ), 7.78-7.76 (d, 1H, Ar H ), 7.57-7.54 (m, 1H, Ar H ), 7.31-7.25 (m, 3H, Ar H ), 6.98-6.96 (d, 1H, Ar H ), 6.86-6.84 (d, 2H, Ar H ), 3.75 (s, 2H, C H 2 ), 3.72 (s, 3H, OC H 3 ), 3.66 (s, 1H, C H ), 3.47 (bs, 1H, C H ), 2.44-2.40 (m, 8H, C H 2 ), 1.64-1.51 (m, 5H, C H 2 ), 1.23-1.09 (m, 5H, C H 2 ); C 29 H 36 N 4 O 3 requires: C, 71.28; H, 7.43; N, 11.47; found C, 71.40; H, 7.75; N, 11.13; Mass (m/z): 489.4 (M+1). 4.7 Biological Activity 4.7.1 Inhibition studies on AChE and BuChE The potential of the test compounds for cholinesterase inhibition was assessed using Ellman's essay.[39–41] The products that were purchased from Sigma-Aldrich included human AChE (product number C1682), equine serum BuChE (CAS 9001-08-5), 5,5’-dithiobis (2-nitrobenzoic acid) (DTNB, product number T-D0944), acetylthiocholine iodide (ATCI, product number T-A0116), and butyrylthiocholine iodide (BTCI, product number T-B0775). Standard drugs were donepezil hydrochloride and tacrine hydrochloride hydrate. Every experiment was conducted at pH 8 in a 50 mM Tris-Hydrochloride buffer (Tris HCl, product number MB030). To ascertain the enzyme inhibitory activity, five distinct doses (0.001−100 μM) of every test chemical were employed. To summarize, 10 μL of the test or reference compounds were incubated in 50 μL of AChE (0.22 U/mL) or 50 μL of BuChE (0.06 U/mL) 4.7.2 Antioxidant activity [1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity] a) Preparation of DPPH reagent: A solution of 2,2-diphenyl-1-picrylhydrazyl (DPPH) (0.1mM) was prepared in methanol. b) Preparation of Sample/Standard Based on the scavenging activity of the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH), free radical scavenging activity of the synthesized compounds was determined by the method of Ali et al [43] . Different volumes (20 – 100μg/ml) of standard compound ascorbic acid and the synthesized compounds were taken from a stock solution in a set of test tubes, and methanol was added to make the volume to 1 ml. To this, 2 ml of 0.1mM DPPH reagent was added and mixed thoroughly. Absorbance at 517 nm was determined after 30 min. C) Preparation of control For control, DPPH (3 ml of 0.1mM solution) was taken and incubated for 30 min at room temperature in dark conditions. The absorbance of the control was taken against methanol (as blank) at 517 nm [44] . The percentage antioxidant activity of the sample/standard was calculated by using the formula: % Inhibition = [(Ab of control- Ab of sample/Ab of control] x 100 The lower the absorbance, the higher the free radical scavenging activity. The curves were prepared and the IC 50 values were calculated using linear regression analysis. 4.7.3 Metal-chelating study The metal chelating ability of all the compounds was assessed using UV spectrophotometry [45]. The absorption spectra of the test compounds (25 μM) alone and in the presence of CuSO 4 , ZnCl 2 , FeSO 4 , FeCl 3 and AlCl 3 (25 μM) in methanol for 30 min were recorded at room temperature in the UV-visible range. 4.7.4 ADME Prediction Before a molecule is introduced into the market, its efficacy and safety are vital considerations. An examination of its ADMET (absorption, distribution, metabolism, excretion, and toxicity) profile can be one way to look at these features [46]. Using the online SwissADME server [47], the ADMET properties of the synthesized compounds were evaluated. 5. Conclusion World’s population is slowly inching towards a continuously growing pool of old-age people every year. Apart from other age-related ailments, Alzheimer’s disease is posing a serious problem in the society. A worrying fact is poor understanding of the disease despite so much of advancements in the medical field, and absence of curative therapeutics. In our quest to develop some acceptable anti-Alzheimer’s agents we used molecular hybridization approach to combine some anti-Alzheimer’s savvy molecular fragments, like piperazine, 8-hydroxyquinoline and acetamido groups into a singular molecular entity to design some potential anti-Alzheimer’s agents. Modifications were made by attaching aromatic/alicyclic amines through acetamide linkers to the 5-(piperazin-1-ylmethyl)quinolin-8-ol scaffold, resulting in a novel series of anti-AD agents. The designed compounds displayed excellent affinity towards both the enzymes with docking scores in the range of -12.8 to -10.6 kcal/mol for AChE, and − 12.4 to -10.3 kcal/mol for BuChE which were higher than the scores obtained for the standard compound’s donepezil (-10.8 kcal/mol) and Tacrine (-8.4 kcal/mol). Among them, compounds having a 4-chloroanilino moiety and a 4-methoxyphenyl group, exhibited the most promising inhibitory activities against AChE (with an IC 50 value of 3.013 µM) and BuChE (with an IC 50 value of 3.144 µM). Compound ( 83 ), with 2-methoxyaniline and 4-fluorobenzene substituents, offered the highest BuChE inhibition with an IC 50 value of 1.888 µM. Additionally, compound (79) offered 93 times higher selectivity for BuChE over AChE. All the compounds displayed metal chelating ability with (Fe + 2 , Fe + 3 , Zn + 2 , Cu + 2 , and Al + 3 ), as well as moderate antioxidant activity. Molecular modelling studies indicated significant interactions between the most potent compounds ( 83 , 95 ) and the PAS and CAS sites of the enzymes. Furthermore, all the compounds offered acceptable in silico pharmacokinetic properties including twenty compounds showing BBB permeability. These results collectively suggested that compound ( 95 ) could be a leading candidate with high potential for further development as a novel anti-AD drug by inhibiting both AChE and BuChE. At the same time, compound (79) can be a potent and selective BuChE Inhibitor. Declarations Acknowledgements We acknowledge Research and development cell, Parul University, Vadodara, Gujarat, India for providing funding as part of intramural research grant for the successful completion of the project. Authors’ contribution M.R. Yadav conceptualized the whole study. A. A. Nagani, M. N. Shah and S. I. Patel carried out the synthesis and data collection, and H. A. Patel and M. N. Shah planned and executed computational studies. V. K. Parikh, A. D. Patel, and B. C. Bhimani assisted in data collection and data interpretation. K. V. Patel designed the biological studies and H. R. Parmar and S. P. Patel performed biological studies and data collection. A. A. Nagani, S. I. Patel, and M. N. Shah drafted the manuscript. All authors reviewed and approved the final version of the manuscript. Conflict of interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this manuscript. The authors declare that they do not have any conflict of interest. The authors declare that this manuscript is original, has not been published before, and is not currently being considered for publication elsewhere. 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Supplementary Files SUPPORTINGINFORMATION.docx Table4.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 11 Apr, 2024 Reviews received at journal 21 Mar, 2024 Reviewers agreed at journal 21 Mar, 2024 Reviewers invited by journal 20 Mar, 2024 Editor assigned by journal 18 Mar, 2024 Submission checks completed at journal 14 Mar, 2024 First submitted to journal 14 Mar, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4098574","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":281113574,"identity":"bc3070be-05ec-41ec-8b15-f6bfa4a6908b","order_by":0,"name":"Afzal Nagani","email":"","orcid":"","institution":"Parul University","correspondingAuthor":false,"prefix":"","firstName":"Afzal","middleName":"","lastName":"Nagani","suffix":""},{"id":281113576,"identity":"01c315b6-6046-4b88-80cf-7d9006eda7b1","order_by":1,"name":"Moksh Shah","email":"","orcid":"","institution":"Parul University","correspondingAuthor":false,"prefix":"","firstName":"Moksh","middleName":"","lastName":"Shah","suffix":""},{"id":281113578,"identity":"d386e93f-9c68-4d7a-a01b-9d44887ee238","order_by":2,"name":"Salman Patel","email":"","orcid":"","institution":"Parul University","correspondingAuthor":false,"prefix":"","firstName":"Salman","middleName":"","lastName":"Patel","suffix":""},{"id":281113580,"identity":"593ace1d-f9c5-4845-8803-c461497cc028","order_by":3,"name":"Harnisha Patel","email":"","orcid":"","institution":"Parul University","correspondingAuthor":false,"prefix":"","firstName":"Harnisha","middleName":"","lastName":"Patel","suffix":""},{"id":281113581,"identity":"6f8ac67d-d1bb-46b8-b4e1-86b8284d82d7","order_by":4,"name":"Vruti Parikh","email":"","orcid":"","institution":"Parul University","correspondingAuthor":false,"prefix":"","firstName":"Vruti","middleName":"","lastName":"Parikh","suffix":""},{"id":281113583,"identity":"c525711a-2098-4158-b13f-126d0895a541","order_by":5,"name":"Ashish Patel","email":"","orcid":"","institution":"Ramanbhai Patel College of Pharmacy, Charusat University","correspondingAuthor":false,"prefix":"","firstName":"Ashish","middleName":"","lastName":"Patel","suffix":""},{"id":281113584,"identity":"e4b55a84-8fbf-4d5a-9a84-8f73420418fe","order_by":6,"name":"Sagar Patel","email":"","orcid":"","institution":"University of Toronto","correspondingAuthor":false,"prefix":"","firstName":"Sagar","middleName":"","lastName":"Patel","suffix":""},{"id":281113585,"identity":"075a55a3-9af0-4fc8-bf21-255f8a0e103f","order_by":7,"name":"Kirti Patel","email":"","orcid":"","institution":"The M.S University of Baroda","correspondingAuthor":false,"prefix":"","firstName":"Kirti","middleName":"","lastName":"Patel","suffix":""},{"id":281113586,"identity":"d3e3138b-854f-47c0-91ba-ca530fb8f016","order_by":8,"name":"Hardik Parmar","email":"","orcid":"","institution":"The M.S University of Baroda","correspondingAuthor":false,"prefix":"","firstName":"Hardik","middleName":"","lastName":"Parmar","suffix":""},{"id":281113587,"identity":"875450bf-5e37-49b2-b6c7-d56f3f7bef3c","order_by":9,"name":"Bhargav Bhimani","email":"","orcid":"","institution":"Piramal Pharma Solution","correspondingAuthor":false,"prefix":"","firstName":"Bhargav","middleName":"","lastName":"Bhimani","suffix":""},{"id":281113588,"identity":"45aaf487-34a0-40bf-bf26-bf233a798790","order_by":10,"name":"M R Yadav","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2UlEQVRIiWNgGAWjYLACHiBiY29gYIYJHCBGiwwfzwEStdjISSQgtOAFurPPGH54U3OYh03yjeHnggobBv72BsbDBXi0mJ3LMZaccwyoRTrHWHrGmTQGiTMHGA7PwKflDI+BNA9bGkiLgTRv22EGA6ALD/Pg12L8m+cfUIvkGePfxGoxAxpuw8MmAWYQpYWtzHJuH1ALT1qZNc+ZNB6JMwcbCGhh3nzjzTcJe/n2w5tv81TYyPG3Nx/+jE8LAwOHAQoDqJixAa8GBgb2B+iMUTAKRsEoGAWoAAB1j0KgzfmwSAAAAABJRU5ErkJggg==","orcid":"","institution":"Parul University","correspondingAuthor":true,"prefix":"","firstName":"M","middleName":"R","lastName":"Yadav","suffix":""}],"badges":[],"createdAt":"2024-03-14 08:12:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4098574/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4098574/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":53079374,"identity":"ec4928e6-df07-47ff-a381-3d10352be795","added_by":"auto","created_at":"2024-03-20 10:22:43","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":41511,"visible":true,"origin":"","legend":"\u003cp\u003eChemical structures of the FDA-approved anti-Alzheimer’s drugs.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-4098574/v1/add2d653058df8403be21f1d.png"},{"id":53079375,"identity":"60b60c93-b847-47f4-ab8f-fd0bf3adf257","added_by":"auto","created_at":"2024-03-20 10:22:43","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":900955,"visible":true,"origin":"","legend":"\u003cp\u003eDesigning strategy for the development of piperazine-quinoline-based MTDLs.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-4098574/v1/929a65060382c4da1088254f.png"},{"id":53079377,"identity":"0211bcb4-8e4a-4e8a-96ef-c66b5b9679bf","added_by":"auto","created_at":"2024-03-20 10:22:43","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1390784,"visible":true,"origin":"","legend":"\u003cp\u003eValidation results of the binding modes of donepezil and tacrine obtained using the AutoDock software. Donepezil, a potent AChE inhibitor (PDB: 7E3H) \u003cstrong\u003e(a);\u003c/strong\u003e and tacrine, a BuChE inhibitor (PDB: 4BDS) \u003cstrong\u003e(b)\u003c/strong\u003e. In green, the crystallographic pose; in red, the top-ranked docking solution.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-4098574/v1/eb57e0048bede90e410984fc.png"},{"id":53079378,"identity":"4a6a6482-03e4-4956-8060-b256989af4f6","added_by":"auto","created_at":"2024-03-20 10:22:43","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1414577,"visible":true,"origin":"","legend":"\u003cp\u003eSuperposed structures of reference drug donepezil and the designed compounds (\u003cstrong\u003e95, 96, 83 \u003c/strong\u003eand \u003cstrong\u003e92\u003c/strong\u003e). \u0026nbsp;(\u003cstrong\u003ea\u003c/strong\u003e) With AChE [PDB: 7E3H] (Donepezil: Green, \u003cstrong\u003e95\u003c/strong\u003e: Blue, \u003cstrong\u003e96\u003c/strong\u003e: Pink). (\u003cstrong\u003eb\u003c/strong\u003e) With BuChE [PDB: 4BDS] (Tacrine: Green, \u003cstrong\u003e83\u003c/strong\u003e: Blue, \u003cstrong\u003e92\u003c/strong\u003e: Pink).\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-4098574/v1/97282d3bc10fc4014bd49888.png"},{"id":53079379,"identity":"d061d043-6349-493b-b67d-f251b864bccb","added_by":"auto","created_at":"2024-03-20 10:22:43","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1660078,"visible":true,"origin":"","legend":"\u003cp\u003eDocking conformations and AChE protein-ligand interactions of reference drug donepezil and the designed molecules. (a) Donepezil; \u003cstrong\u003e(b)\u003c/strong\u003e \u003cstrong\u003ecompound (95); (c) compound (96).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-4098574/v1/a8848bd60855370c628aa0e7.png"},{"id":53079842,"identity":"29dffdc4-6351-4705-9686-aa077c670558","added_by":"auto","created_at":"2024-03-20 10:30:43","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":2304504,"visible":true,"origin":"","legend":"\u003cp\u003eDocking conformations and BuChE protein-ligand interactions of compounds. (\u003cstrong\u003ea\u003c/strong\u003e) Tacrine; (\u003cstrong\u003eb\u003c/strong\u003e) compound (\u003cstrong\u003e83\u003c/strong\u003e); (\u003cstrong\u003ec\u003c/strong\u003e) compound (\u003cstrong\u003e92\u003c/strong\u003e).\u003c/p\u003e","description":"","filename":"Figure6.png","url":"https://assets-eu.researchsquare.com/files/rs-4098574/v1/e84dea1dbf3da8e4c39c020b.png"},{"id":53080544,"identity":"eb323aa5-112b-40d7-be6a-59178350a974","added_by":"auto","created_at":"2024-03-20 10:38:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3915937,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4098574/v1/b9966c5a-a0f5-464b-b2c5-5764801cfb67.pdf"},{"id":53079381,"identity":"e2b16488-d720-40b8-9a5f-2b05e9e123da","added_by":"auto","created_at":"2024-03-20 10:22:44","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":11504889,"visible":true,"origin":"","legend":"","description":"","filename":"SUPPORTINGINFORMATION.docx","url":"https://assets-eu.researchsquare.com/files/rs-4098574/v1/7ce59f56333bfdbc176bf791.docx"},{"id":53079841,"identity":"7a0668d8-902d-43e7-a8a4-bb4d38a341b8","added_by":"auto","created_at":"2024-03-20 10:30:43","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":115664,"visible":true,"origin":"","legend":"","description":"","filename":"Table4.docx","url":"https://assets-eu.researchsquare.com/files/rs-4098574/v1/34197ed22d8589478bfef4f7.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Unveiling Piperazine-Quinoline Hybrids as Potential Multi-Target Directed Anti- Alzheimer’s Agents: Design, Synthesis and Biological Evaluation","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eAlzheimer's disease (AD) is a neurodegenerative disorder characterized by memory loss and dementia which poses a significant global health challenge accounting for more than 55\u0026nbsp;million cases worldwide, with nearly 10\u0026nbsp;million new cases emerging annually. The disease is named after a German psychiatrist Alois Alzheimer who first described it in the year 1906 [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The exact etiology of the disease still remains unknown. Certain hypotheses, such as deposition of β-amyloid (Aβ) plaques in the neurons, increase in the levels of acetylcholinesterase and butyrylcholinesterase neurotransmitters, neurofibrillary tangles (NFT), tau protein hyperphosphorylation, dyshomeostasis of biometals, and oxidative stress have been proposed as the causative factors for the genesis of the disease. Currently, a limited number of drugs are available to treat Alzheimer\u0026rsquo;s disease which include donepezil, rivastigmine, galantamine (all acetylcholinesterase inhibitors) and memantine, an \u003cem\u003eN\u003c/em\u003e-methyl-\u003cem\u003eD\u003c/em\u003e-aspartate (NMDA) receptor antagonist [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], that can either temporarily delay clinical deterioration or improve the symptoms associated with AD (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Due to the involvement of multiple factors in AD, the conventional approach of \u0026ldquo;one molecule one target\u0026rdquo; pattern proves inadequate for the management of the disease. Hence, an appropriate strategy for developing multi-targeted directed therapy could be adopted to counter the causative factors involved in the pathogenesis of AD [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAcetylcholine (ACh) a neurotransmitter, vital for cognitive functions including memory and physiological regulation, is found in the synapses of the neurons. ACh is broken down into acetic acid and choline, primarily by the enzyme acetylcholinesterase (AChE) and, to a lesser extent by butyrylcholinesterase (BuChE) secreted by glial cells. AChE's interaction with nonamyloidogenic amyloid-β (Aβ) motivated the researchers to target the AChE in cognitive disorder studies [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In a healthy brain, Ach is hydrolyzed by AChE, but with progression of the Alzheimer\u0026rsquo;s, the level of AChE drops, and the level of BuChE enhances by 40 to 90% in the brain's hippocampus and temporal cortex areas. BuChE is also correlated with the abnormal β-amyloid (Aβ) deposition [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Therefore, BuChE can be a promising target for the development of novel drugs for the treatment of AD [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAs the brain ages, body\u0026rsquo;s antioxidant defense mechanism weakens and an imbalance in reactive oxygen species (ROS) production occurs, increasing the risk of AD. Oxidative stress aggravates AD\u0026rsquo;s progression leading to the formation of amyloid plaques and neurofibrillary tangles in the brain. To tackle AD, researchers are focusing on reducing the levels of free radicals in the brain. Recent research has revealed the therapeutic potential of compounds that can simultaneously inhibit AChE, disaggregate amyloid beta, and reduce inflammation. This multifaceted approach targets multiple aspects of AD's origin and progression, offering new avenues for developing anti-Alzheimer's therapeutics [\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAD is marked by higher levels of metal ions in the brain which include Cu\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e, Zn\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e, Fe\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e, Fe\u003csup\u003e+\u0026thinsp;3\u003c/sup\u003e and Al\u003csup\u003e+\u0026thinsp;3\u003c/sup\u003e, with particular emphasis on Cu\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e and Zn\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e. These metals readily bind to Aβ, causing toxic Aβ oligomer aggregation in the brain [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Iron is instrumental in impacting neurotransmitters, oxygen transport, cellular respiration, and DNA synthesis in the brain [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Elevated levels of iron are found in brain-damaged areas of AD patients, correlating significantly with Aβ plaques and Tau pathology [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Zinc, the second most abundant trace element in the human body after iron, also plays a role in AD. A meta-analysis from 1984 to 2014 showed decreased serum zinc levels in AD individuals [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Conversely, increased Zn levels in the cerebral cortex are associated with Aβ pathology and severity of dementia [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Research in recent years, has explored the link between AD and abnormal copper (Cu) metabolism. Genetic evidence suggests that genes regulating copper pathways contribute to AD susceptibility, which is supported by various studies [\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Variations in copper levels in serum, plasma, cerebrospinal fluid (CSF) and the brain are linked to cognitive deficits and AD development [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e"},{"header":"2. Designing Strategy","content":"\u003cp\u003eStructure-based drug design approach was used to design new multi-target directed ligands as promising anti-Alzheimer\u0026rsquo;s agents. Piperazine scaffold has displayed versatile applications and played a vital role in drug discovery. It is associated with molecules exhibiting various activities such as anti-cancer, anti-diabetic, anti-histaminic, anti-Alzheimer\u0026rsquo;s, and also it has shown improved ADME properties along with better BBB penetration when incorporated into a molecular system. Piperazine, a bioisostere of piperidine, has been used to mimic the piperidine ring present in donepezil, and many piperazine-based AChE inhibitors have been developed, such as a piperazine derivative FK960, which has shown beneficial effects in memory deficits in Alzheimer's rats and monkeys [\u003cspan additionalcitationids=\"CR25 CR26 CR27 CR28\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Therefore, in the current study we have designed some novel molecules by incorporating piperazine into a molecular frame work utilizing multi-component Petasis reaction in the synthetic scheme.\u003c/p\u003e \u003cp\u003eQuinoline is a privileged scaffold present in a wide variety of natural and synthetic compounds demonstrating an array of pharmacological properties. Quinoline derivatives have been found to possess a range of biological activities, such as anti-cancer, anti-malarial, analgesic, anti-tubercular, anti-bacterial, anti-protozoal, anti-glycemic, anti-inflammatory, anti-fungal, anti-hypertensive, anti-HIV, and anti-helminthic [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Recent research indicates that certain quinoline derivatives possess significant anti-acetylcholinesterase (AChE) and anti-butyrylcholinesterase (BuChE) effects. Molecular docking studies suggest that the quinoline fragment can bind to the peripheral anionic site (PAS) of AChE through π-π stacking interaction [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Also, the reported metal chelation property of quinoline in desferrioxamine [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], clioquinol (CQ) [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e], and 8-hydroxyquinoline derivative (PBT2) [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e] makes quinoline a potential molecular framework for anti-Alzheimer's drug discovery crusade [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Hence, in the present study, we report the design and development of some piperazine-quinoline analogs as multi-target directed ligands (MTDLs) using multicomponent Petasis reaction, which may open new horizons for a fundamentally novel treatment for Alzheimer's disease (AD). These MTDLs were evaluated for their efficacy for AChE inhibition, BuChE inhibition, metal chelation, and antioxidants. The designing strategy is being displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"3. Results and discussion","content":"\u003cp\u003e\u003cstrong\u003e3. 1 Molecular Docking\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo validate the rationale behind the design of the hybrid molecules the designed compounds and some reference molecules were subjected to molecular modeling studies (\u003cstrong\u003eFigure 3\u003c/strong\u003e)\u003cstrong\u003e.\u003c/strong\u003e Molecular docking studies were performed to check drug-receptor interactions, which are responsible for binding the ligands to the target proteins leading to enzyme inhibitory activity by the designed molecules. Hence, different interactions between the ligands and the target proteins were analyzed. The molecular superposition approach was validated by comparison with the original crystallographic structure of the AChE-Donepezil complex (PDB ID 7E3H) (\u003cem\u003eHuman\u003c/em\u003e\u003cem\u003e)\u003c/em\u003e [37], and BuChE-Tacrine complex (PDB ID 4BDS) (\u003cem\u003eHuman\u003c/em\u003e) [38]. The most accurately positioned slots obtained were assessed. The outcomes are depicted in \u003cstrong\u003eFigure 3\u003c/strong\u003e, demonstrating the alignment of the proposed binding modes for the inhibitors within the active sites of AChE and BuChE. This alignment yielded a superposition RMSD of 1.07 \u0026Aring; for donepezil (PDB ID 7E3H) [37] and 0.70 \u0026Aring; for Tacrine (PDB ID 4BDS) [2, 38]. These values fall very much within the widely accepted tolerance threshold of 2.0 \u0026Aring;.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe study employed molecular docking with AutoDock Tools 1.5.7 and AutoDock Vina to calculate the binding energies of the synthesized ligands with the target proteins, acetylcholinesterase (\u003cem\u003eh\u003c/em\u003eAChE, PDB ID: 7E3H) [38] and butyrylcholinesterase (\u003cem\u003eh\u003c/em\u003eBuChE, PDB ID: 4BDS) [37]. The results are summarized in \u003cstrong\u003eTable 1\u003c/strong\u003e, revealing the \u0026nbsp; docking scores of the designed compounds ranging from \u003cstrong\u003e-12.6 kcal/mol\u0026nbsp;\u003c/strong\u003eto\u003cstrong\u003e\u0026nbsp;-9.4 kcal/mol\u003c/strong\u003e for \u003cem\u003eh\u003c/em\u003eAChE and -\u003cstrong\u003e12.4 kcal/mol\u003c/strong\u003e to\u003cstrong\u003e\u0026nbsp;-10.3 kcal/mol\u003c/strong\u003e for BuChE respectively.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1:\u003c/strong\u003e Docking score of the designed compounds for \u003cem\u003eh\u003c/em\u003eAChE \u0026amp; \u003cem\u003eh\u003c/em\u003eBuChE\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"425\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eComp.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"35.05882352941177%\" colspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eAffinity (kcal/mol)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eComp.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.88235294117647%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAffinity (kcal/mol)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"22.525597269624573%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eh\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003eAChE (7E3H)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.986348122866893%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eh\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003eBuChE (4BDS)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.549488054607508%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eh\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003eAChE (7E3H)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.938566552901023%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eh\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003eBuChE (4BDS)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e71\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-10.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-11.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e86\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-12.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e72\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-9.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-12.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e87\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-12.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e73\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-11.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-11.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e88\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-12.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e74\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-12.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-11.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e89\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-11.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e75\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-10.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e90\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-11.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-12.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e76\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-12.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e91\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-12.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e77\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-9.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-10.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e92\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-9.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e78\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-12.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-10.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e93\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-11.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-10.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e79\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-10.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-11.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e94\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-11.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e80\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-12.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-11.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e95\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-11.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e81\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-11.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-12.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e96\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-12.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e82\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-12.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e97\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-11.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-11.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e83\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-12.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-11.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003eTacrine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\"\u003e\n \u003cp\u003e-8.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.529411764705882%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e84\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\"\u003e\n \u003cp\u003e-12.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.294117647058822%\"\u003e\n \u003cp\u003e-10.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.529411764705882%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eDonep-ezil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.235294117647058%\" rowspan=\"2\"\u003e\n \u003cp\u003e-11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.88235294117647%\" rowspan=\"2\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"30.8411214953271%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e85\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.8411214953271%\"\u003e\n \u003cp\u003e-9.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"38.3177570093458%\"\u003e\n \u003cp\u003e-11.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eThe findings indicated that\u0026nbsp;all of the designed compounds assumed a consistent configuration when binding to AChE and BuChE enzymes, engaging with various amino acid fragments present in the enzymes\u0026rsquo; catalytic active sites (CAS) and peripheral anionic sites (PAS) (\u003cstrong\u003eTables 2\u003c/strong\u003e and \u003cstrong\u003e3\u003c/strong\u003e). The findings demonstrated that all the compounds exhibited favorable fitting into the catalytic active site (CAS) and displayed effective interactions with the peripheral anionic site (PAS) of AChE and showed good binding affinity, akin to the reference inhibitor donepezil (-11.4 kcal/mol), as depicted in \u003cstrong\u003eFigure 4\u003c/strong\u003e. Upon close examination of the compounds, it was observed that in the PAS, the amino acid residues TYR341 and TRP286 were engaged in \u0026pi;-\u0026pi; stacking interactions with the quinoline ring of the designed molecules. Additionally, SER289 and ARG289 formed hydrogen bonds, while PHE331 participated in \u0026pi;-\u0026pi; stacking. TRP84 and GLN69 were also involved in hydrogen bonding. Furthermore, amino acid residues SER125 and GLY121 in the CAS, interacted via hydrogen bonding with the oxygen atom of the amide linker. In the mid gorge region, TRP86 was involved in \u0026pi;-\u0026pi; stacking and TYR337 in \u0026pi;-sigma bonding. Other amino acid residues, including GLU202, PHE288, ASP74, and GLY448 also contributed to favorable interactions with the molecules. \u003cstrong\u003eFigure 5 and Table 2\u003c/strong\u003e depicting amino acid interactions of \u003cem\u003ein vitro\u003c/em\u003e most active compound \u003cstrong\u003e95\u003c/strong\u003e and compound having lowest binding energy \u003cstrong\u003e96\u003c/strong\u003e for AChE.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2:\u003c/strong\u003e Docking scores and amino acid interactions of the standard drug donepezil and compounds (\u003cstrong\u003e95\u003c/strong\u003e \u0026amp; \u003cstrong\u003e96\u003c/strong\u003e) in the specific regions of \u003cem\u003eh\u003c/em\u003eAChE (7E3H).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"618\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.724919093851133%\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eCompound\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.414239482200648%\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eScore\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"76.86084142394822%\" colspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003eInteraction with the amino acid fragments\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.473684210526315%\"\u003e\n \u003cp\u003e\u003cstrong\u003ePeripheral anionic site (PAS)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.894736842105264%\"\u003e\n \u003cp\u003e\u003cstrong\u003eCatalytic active site (CAS)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"40.63157894736842%\"\u003e\n \u003cp\u003e\u003cstrong\u003eMid-gorge\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.724919093851133%\" valign=\"top\"\u003e\n \u003cp\u003eDonepezil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.414239482200648%\" valign=\"top\"\u003e\n \u003cp\u003e-11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.653721682847895%\" valign=\"top\"\u003e\n \u003cp\u003eTRP286, TYR341,\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.977346278317153%\" valign=\"top\"\u003e\n \u003cp\u003ePHE295, VAL294\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.22977346278317%\" valign=\"top\"\u003e\n \u003cp\u003eTRP86, TYR337, TYR72, PHE228\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.724919093851133%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e95\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.414239482200648%\" valign=\"top\"\u003e\n \u003cp\u003e-11.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.653721682847895%\" valign=\"top\"\u003e\n \u003cp\u003eTRP286, TYR341\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.977346278317153%\" valign=\"top\"\u003e\n \u003cp\u003eGLY448, GLY121\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.22977346278317%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;PHE338\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.724919093851133%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e96\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.414239482200648%\" valign=\"top\"\u003e\n \u003cp\u003e-12.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.653721682847895%\" valign=\"top\"\u003e\n \u003cp\u003eTRP286, PHE330\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.977346278317153%\" valign=\"top\"\u003e\n \u003cp\u003eSER125\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"31.22977346278317%\" valign=\"top\"\u003e\n \u003cp\u003eTRP86, TYR337\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eIn case of BuChE, docking scores of the designed compounds ranged from -12.4 kcal/mol to -10.3 kcal/mol. Further analysis of the interactions between the designed compounds and the protein was conducted. The results showed that all designed compounds effectively occupied the catalytic active site (CAS) and interacted favorably with the peripheral anionic site (PAS) of BuChE, mirroring the behavior of the reference inhibitor tacrine (-8.4 kcal/mol). Upon closer examination of all of the designed compounds, it was observed that the amino acid residue TRP231 was engaged in a \u0026pi;-alkyl interaction with the designed molecules in the PAS. Additionally, LEU286 and PHE329 fragments exhibited \u0026pi;-alkyl interactions in the mid-gorge region of the enzyme, and GLY116 and GLY119 also showed interactions in the same region. In the CAS, amino acid residues TRP82 and HIS438 displayed \u0026pi;-\u0026pi; stacking interactions with the quinoline ring, ALA328 displayed \u0026pi;-alkyl interaction, and many compounds displayed interactions with MET437 and TYR440 residues of the CAS region. \u003cstrong\u003eFigure 6 and Table 3\u003c/strong\u003e depicting amino acid interactions of \u003cem\u003ein vitro\u003c/em\u003e most active compounds \u003cstrong\u003e83 and 92 for BuChE.\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable-3:\u003c/strong\u003e Docking score and amino acid interactions of the standard drug tacrine and the compounds (\u003cstrong\u003e83\u003c/strong\u003e \u0026amp; \u003cstrong\u003e92\u003c/strong\u003e) in the specific regions of BuChE (4BDS).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"670\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"13.582089552238806%\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eCompound\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.7611940298507465%\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eScore\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"78.65671641791045%\" colspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003eInteraction with the amino acid fragments\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"26.565464895635674%\"\u003e\n \u003cp\u003e\u003cstrong\u003ePeripheral anionic site (PAS)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"35.86337760910816%\"\u003e\n \u003cp\u003e\u003cstrong\u003eCatalytic active site (CAS)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"37.571157495256166%\"\u003e\n \u003cp\u003e\u003cstrong\u003eMid-gorge\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"13.582089552238806%\" valign=\"top\"\u003e\n \u003cp\u003eTacrine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.7611940298507465%\" valign=\"top\"\u003e\n \u003cp\u003e-8.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.895522388059703%\" valign=\"top\"\u003e\n \u003cp\u003eTRP231\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.208955223880597%\" valign=\"top\"\u003e\n \u003cp\u003eHIS438, SER198\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.55223880597015%\" valign=\"top\"\u003e\n \u003cp\u003eGLY116, GLY117, PHE329\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"13.582089552238806%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e83\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.7611940298507465%\" valign=\"top\"\u003e\n \u003cp\u003e-11.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.895522388059703%\" valign=\"top\"\u003e\n \u003cp\u003eTRP231\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.208955223880597%\" valign=\"top\"\u003e\n \u003cp\u003eTRP82, HIS438, TYR440, SER198\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.55223880597015%\" valign=\"top\"\u003e\n \u003cp\u003eLEU286, PHE329, GLY117, GLY119\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"13.582089552238806%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e92\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.7611940298507465%\" valign=\"top\"\u003e\n \u003cp\u003e-11.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.895522388059703%\" valign=\"top\"\u003e\n \u003cp\u003eTRP231\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.208955223880597%\" valign=\"top\"\u003e\n \u003cp\u003eTRP82, HIS438,\u0026nbsp;SER198\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.55223880597015%\" valign=\"top\"\u003e\n \u003cp\u003eGLY116, GLY117, LEU286, PHE329\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e3.2 Chemistry\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe designed compounds were synthesized using a sequence of reactions as shown in \u003cstrong\u003eScheme-1\u003c/strong\u003e. \u003cem\u003eN-Boc\u003c/em\u003e-piperazine (\u003cstrong\u003e1\u003c/strong\u003e), glyoxalic acid (\u003cstrong\u003e3\u003c/strong\u003e), and boronic acids (\u003cstrong\u003e2a \u0026ndash; 2c\u003c/strong\u003e) were reacted in the first step utilizing Petasis-Mannich multicomponent reaction in the presence of ACN solvent to obtain the intermediates (\u003cstrong\u003e4 - 6\u003c/strong\u003e). In step 2, these intermediates were coupled with substituted aromatic/cyclic amines (\u003cstrong\u003e7 \u0026ndash; 15\u003c/strong\u003e) through acid-amine coupling reaction in the presence of EDC.HCl, HOBt and triethylamine to obtain the amides (\u003cstrong\u003e16 \u0026ndash; 42\u003c/strong\u003e), followed by deprotection of Boc using dioxane HCl. The designed compounds were obtained by reacting the resulting intermediates (\u003cstrong\u003e43 \u0026ndash; 69\u003c/strong\u003e) with 5-chloromethyl-8-hydroxyquinoline (\u003cstrong\u003e70\u003c/strong\u003e) in the presence of triethylamine at 100 \u003csup\u003eo\u003c/sup\u003eC in the presence of DMSO as a solvent. The chloromethyl derivative (\u003cstrong\u003e70\u003c/strong\u003e) was obtained by chloromethylation of 8-hydroxyquinoline using formaldehyde and hydrogen chloride gas.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3 Anti-Alzheimer\u0026rsquo;s Activity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll of the synthesized piperazine derivatives (\u003cstrong\u003e71 \u0026ndash; 79, 80 \u0026ndash; 88,\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;89 \u0026ndash; 97\u003c/strong\u003e) were evaluated for anticholinesterase activity against human AChE and equine BuChE enzymes, and for their metal chelation and antioxidant properties to determine their potential application against Alzheimer\u0026rsquo;s disease. AChE and BuChE inhibitory assays were performed by Ellman\u0026rsquo;s enzyme assay where we determined the IC\u003csub\u003e50\u003c/sub\u003e values of all the designed compounds and compared them with standard drugs, donepezil for AChE inhibition and tacrine for BuChE inhibition.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAnti-oxidant activity of nine compounds were evaluated using the DPPH method with ascorbic acid as the reference compound. The metal chelation potential of the synthesized compounds was assessed for the biologically significant metal ions such as Fe\u003csup\u003e+2\u003c/sup\u003e, Fe\u003csup\u003e+3\u003c/sup\u003e, Cu\u003csup\u003e+2\u003c/sup\u003e, Zn\u003csup\u003e+2\u003c/sup\u003e, and Al\u003csup\u003e+3\u003c/sup\u003e. The results indicated that most of the compounds showed moderate AChE inhibitory activity but excellent BuChE inhibitory activity. These compounds also exhibited significant antioxidant and metal chelating properties.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 Cholinesterase inhibitory activity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIC\u003csub\u003e50\u003c/sub\u003e values of all the synthesized compounds were determined using Ellman\u0026rsquo;s essay. Human AChE enzyme was used for determining acetylcholinesterase inhibition and Equine BuChE enzyme was utilized for butyrylcholinesterase inhibitory activities. The synthesized compounds showed low to moderate IC\u003csub\u003e50\u003c/sub\u003e values for AChE inhibition, wherein twenty-seven\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003ecompounds offered \u003cstrong\u003eIC\u003csub\u003e50\u003c/sub\u003e\u003c/strong\u003e values under\u0026nbsp;100\u0026nbsp;\u0026micro;M\u0026nbsp;with compound (\u003cstrong\u003e95)\u003c/strong\u003e showing the \u003cstrong\u003ehighest activity\u003c/strong\u003e with an IC\u003csub\u003e50\u003c/sub\u003e value of \u003cstrong\u003e3.013\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u0026micro;M\u003c/strong\u003e. Compounds (\u003cstrong\u003e81, 82\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;78\u003c/strong\u003e)\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eoffered 50 % inhibition at concentrations of 8.06, 21.85, and 30.92\u0026nbsp;\u0026micro;M. It is important to note that substitution with electron releasing group (OCH\u003csub\u003e3\u003c/sub\u003e) (\u003cstrong\u003e89 - 97\u003c/strong\u003e) or a small sized atom (F) (\u003cstrong\u003e80 - 88\u003c/strong\u003e) on the 4\u003csup\u003eth\u003c/sup\u003e position of the benzyl ring shows improved activity\u0026nbsp;compared to the un-substituted derivatives (\u003cstrong\u003e71 - 79\u003c/strong\u003e). Furthermore, substitution on the aniline ring also has a significant effect in improving or reducing the inhibitory activity whereby substitution with electron-withdrawing groups (Cl or F) on the 4\u003csup\u003eth\u003c/sup\u003e position in the series containing 4-methoxybenzyl ring (\u003cstrong\u003e89 \u0026ndash; 97\u003c/strong\u003e) showed improved activity with IC\u003csub\u003e50\u003c/sub\u003e values of 3.013 \u0026micro;M and 45.27 \u0026micro;M for compounds (\u003cstrong\u003e95\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;89)\u003c/strong\u003e. Additionally, attachment of electron releasing groups (CH\u003csub\u003e3\u003c/sub\u003e, and OCH\u003csub\u003e3\u003c/sub\u003e) on \u003cem\u003eortho\u003c/em\u003e or \u003cem\u003epara\u003c/em\u003e position in the series with electron-withdrawing group (F) on the benzyl ring showed excellent activity wherein \u003cem\u003eortho\u003c/em\u003e substitution\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eof methyl \u003cstrong\u003e(81)\u003c/strong\u003e and methoxyl\u003cstrong\u003e\u0026nbsp;(83)\u0026nbsp;\u003c/strong\u003egroups showed IC\u003csub\u003e50\u003c/sub\u003e values of 8.056 and 14.09 \u0026micro;M respectively, and \u003cem\u003epara\u003c/em\u003e substitution of methyl \u003cstrong\u003e(82)\u003c/strong\u003e group gave 50 % inhibition at 21.85 \u0026micro;M. Moreover, it is important to note that unsubstituted aniline or cyclohexamine showed the poorest activity against AChE enzyme. Hence, we can say that substitution of electron releasing or electronegative groups on both the rings, benzyl as well as aniline is important for activity\u003cstrong\u003e.\u0026nbsp;\u003c/strong\u003e When both the functional groups are present in the compounds it offered significant AChE inhibition.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFor the butyrylcholinesterase inhibition, all the compounds exhibited excellent inhibitory activity with IC\u003csub\u003e50\u003c/sub\u003e values below 12.42 \u0026micro;M,\u0026nbsp;with compounds containing \u003cem\u003eo\u003c/em\u003e-methoxy substituent on the aniline ring showing the best IC\u003csub\u003e50\u003c/sub\u003e value of 1.88 \u0026micro;M for the 4-fluoro substituted benzyl derivative \u003cstrong\u003e(83),\u0026nbsp;\u003c/strong\u003e2.217 \u0026micro;M for 4-methoxy benzyl derivative \u003cstrong\u003e(92),\u003c/strong\u003e and 3.732 \u0026micro;M for unsubstituted benzyl derivative \u003cstrong\u003e(74).\u0026nbsp;\u003c/strong\u003e4-Chloro substituted aniline derivatives also showed excellent BuChE inhibition with IC\u003csub\u003e50\u003c/sub\u003e values of 5.182, 2.02, and 3.133 \u0026micro;M for compounds (\u003cstrong\u003e77, 86\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;95)\u003c/strong\u003e respectively. Notably, cyclohexylamino and unsubstituted anilino derivatives, which proved poor AChE inhibitors offered high selectivity for BuChE with low IC\u003csub\u003e50\u003c/sub\u003e values. The anilino derivative\u003cstrong\u003e\u0026nbsp;(71)\u003c/strong\u003e showed an IC\u003csub\u003e50\u003c/sub\u003e value of 5.740 \u0026micro;M which was 25 times\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003elower than the value obtained for AChE inhibition, whereas the cyclohexylamino derivative\u003cstrong\u003e\u0026nbsp;(79)\u003c/strong\u003e offered 93 times higher selectivity for BuChE with an IC\u003csub\u003e50\u003c/sub\u003e of 2.288 \u0026micro;M\u003cstrong\u003e.\u0026nbsp;\u003c/strong\u003eAnilino derivatives\u003cstrong\u003e\u0026nbsp;(80\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;89)\u003c/strong\u003e accounted for IC\u003csub\u003e50\u003c/sub\u003e values of 8.17 and 5.94 \u0026micro;M respectively, and cyclohexylamino derivatives\u003cstrong\u003e\u0026nbsp;(88\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;97)\u003c/strong\u003e yielded IC\u003csub\u003e50\u003c/sub\u003e values of 6.509 and 8.368 \u0026micro;M for compounds\u003cstrong\u003e\u0026nbsp;(88\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;97)\u0026nbsp;\u003c/strong\u003eyielding more than 18 times higher selectivity for butyrylcholinesterase.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5 Anti-oxidant and Metal chelation properties\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe antioxidant property was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH)\u0026nbsp;radical scavenging activity of some selected compounds. Top nine\u0026nbsp;cholinesterase inhibitors \u003cstrong\u003e(78, 79, 81, 82, 83, 84, 86, 92 and 95)\u003c/strong\u003e were evaluated for their antioxidant properties and the activities were compared with ascorbic acid as a standard. The essay was performed by taking 20-100\u0026nbsp;\u0026micro;g/ml\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003econcentrations of the test and the standard compounds and evaluated for inhibition of 0.1 mM DPPH free radicals. Results indicated that all the nine compounds showed inhibition wherein compounds (\u003cstrong\u003e78, 83\u003c/strong\u003e and \u003cstrong\u003e86\u003c/strong\u003e) have shown the highest activity amongst the screened compounds. These three compounds (\u003cstrong\u003e78, 83\u003c/strong\u003e and \u003cstrong\u003e86\u003c/strong\u003e) showed \u003cstrong\u003e42.13 %,\u003c/strong\u003e \u003cstrong\u003e39.33 %,\u003c/strong\u003e and\u0026nbsp;\u003cstrong\u003e37.18 %\u003c/strong\u003e inhibition\u0026nbsp;respectively,\u0026nbsp;at \u003cstrong\u003e20\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u0026micro;g/ml\u0026nbsp;\u003c/strong\u003econcentration against \u003cstrong\u003e52.54 %\u003c/strong\u003e shown by the ascorbic acid. At \u003cstrong\u003e100 \u0026micro;g/ml\u0026nbsp;\u003c/strong\u003econcentration, \u003cstrong\u003e78\u003c/strong\u003e exhibited an inhibition of\u0026nbsp;\u003cstrong\u003e55.17 %,\u003c/strong\u003e and its IC\u003csub\u003e50\u003c/sub\u003e value was found to be \u003cstrong\u003e73.12 \u0026mu;g/ml\u003c/strong\u003e, and \u003cstrong\u003e83\u003c/strong\u003e exhibited an inhibition of \u003cstrong\u003e52.91 %,\u003c/strong\u003e and its IC\u003csub\u003e50\u0026nbsp;\u003c/sub\u003evalue was found to be \u003cstrong\u003e81.65 \u0026mu;g/ml\u003c/strong\u003e. Similarly, \u003cstrong\u003e86\u003c/strong\u003e exhibited an inhibition of \u003cstrong\u003e51.4 %\u003c/strong\u003e in\u0026nbsp;the DPPH radical scavenging activity, and its IC\u003csub\u003e50\u003c/sub\u003e value was found to be \u003cstrong\u003e90.73 \u0026mu;g/ml\u003c/strong\u003e. Ascorbic acid was used as a reference compound which exhibited a percent inhibition of \u003cstrong\u003e87.56 %\u003c/strong\u003e and offered an IC\u003csub\u003e50\u003c/sub\u003e value of \u003cstrong\u003e13.98 \u0026mu;g/ml\u003c/strong\u003e (\u003cstrong\u003eTable 5)\u003c/strong\u003e. All the compounds displayed metal chelating ability with (Fe\u003csup\u003e+2\u003c/sup\u003e, Fe\u003csup\u003e+3\u003c/sup\u003e, Zn\u003csup\u003e+2\u003c/sup\u003e, Cu\u003csup\u003e+2\u003c/sup\u003e, and Al\u003csup\u003e+3\u003c/sup\u003e) due to the presence of 8-hydroxyquinoline moiety present in these molecules (\u003cstrong\u003eTable 4\u003c/strong\u003e)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 5:\u003c/strong\u003e Antioxidant potential of compounds (\u003cstrong\u003e78, 79, 81, 82, 83, 84, 86, 92 and 95\u003c/strong\u003e)\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" rowspan=\"3\"\u003e\n \u003cp\u003eCompounds\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"58.18181818181818%\" colspan=\"5\"\u003e\n \u003cp\u003e\u003cstrong\u003eConcentration (\u0026micro;g/ml)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" rowspan=\"3\"\u003e\n \u003cp\u003eIC\u003csub\u003e50\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(\u0026micro;g/ml)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.375%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.125%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.125%\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.625%\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.75%\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"5\"\u003e\n \u003cp\u003e% Inhibition\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003eAscorbic Acid\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e52.538\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e61.450\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e70.362\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e79.792\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e87.564\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e13.98\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e78\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e42.133\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e44.935\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e46.443\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e50.862\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e55.172\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e73.125\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003e79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e44.145\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e45.284\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e47.150\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e48.290\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e49.326\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e108.787\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003e81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e34.590\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e38.362\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e41.163\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e44.935\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e49.137\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e107.134\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003e82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e35.668\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e39.331\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e41.702\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e44.181\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e48.599\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e113.202\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e83\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e39.331\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e42.887\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e47.090\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e49.568\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e52.909\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e81.65\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003e84\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e43.316\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e44.041\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e44.870\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e45.595\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e46.424\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e197.105\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e86\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e37.176\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e40.301\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e46.012\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e47.737\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e51.400\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e90.726\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003e92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e41.761\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e42.072\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e43.730\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e44.455\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e46.943\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e159.365\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.727272727272727%\" valign=\"top\"\u003e\n \u003cp\u003e95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e31.896\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e35.991\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.545454545454545%\"\u003e\n \u003cp\u003e40.409\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12%\"\u003e\n \u003cp\u003e43.965\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.909090909090908%\"\u003e\n \u003cp\u003e48.060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.090909090909092%\" valign=\"top\"\u003e\n \u003cp\u003e109.601\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e3.6 ADME Prediction\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn order to exhibit anti-Alzheimer activity, crossing of blood brain barrier by a test compound, is one of the key attributes, which was determined using SwissADME along with other key pharmacokinetic properties of the synthesized compounds. The results were promising, and all the compounds except compounds (\u003cstrong\u003e74, 75, 78, 87, 92, 93\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;96)\u003c/strong\u003e were found to cross BBB. Moreover, all the compounds indicated good bioavailability of\u0026nbsp;\u003cstrong\u003e0.55\u0026nbsp;\u003c/strong\u003eand high GI absorption. Thus, it could be said that twenty compounds out of the twenty-seven synthesized compounds, including those exhibiting promising \u003cem\u003ein vitro\u003c/em\u003e cholinesterase inhibition, possess excellent pharmacokinetic properties and they have high probability to reach the active site and show anti-Alzheimer activity.\u003c/p\u003e"},{"header":"4. Experimental","content":"\u003cp\u003e4.1\u003cem\u003e \u003c/em\u003eDocking protocol\u003c/p\u003e\n\u003cp\u003eThe ADT software and Autodock vina program were employed for molecular docking to assess the interaction between the designed analogs and the targeted enzymes (AChE \u0026amp; BuChE). This was aimed to corroborate the findings from both \u003cem\u003ein vitro\u003c/em\u003e and \u003cem\u003ein silico\u003c/em\u003e analyses. Utilizing PDB codes 7E3H for AChE and 4BDS for BuChE from the RCSB protein databank (http://www.rcsb.org), crystal structures of the targets were retrieved. Autodock vina necessitates the ligand as well as the receptor in pdbqt format. The ADT software was utilized to prepare the two enzymes and the ligands. In the process of protein preparation, all water molecules were removed, followed by the addition of polar hydrogens and Kollman charges. Subsequently, active sites were determined by creating grid boxes sized 40 \u0026times; 40 \u0026times; 40 \u0026Aring; for AChE and for BuChE around the binding domains of each co-crystallized ligands with the respective enzyme coordinates: center_x = -43.36, center_y = 37.72, center_z = -30.31 for AChE, and center_x = 132.8, center_y = 115.68, center_z = 41.43 for BuChE. To validate the docking protocol, the docked ligands were removed from the co-crystallized structures, and re-docking both of the ligands, i.e. donepezil for AChE and tacrine for BuChE, followed by calculating the Root-Mean-Square Deviation (RSMD) between the co-crystalized ligands and the re-docked poses. For analysis of the docking results and visualization of ligand-receptor interactions, Discovery Studio 2021 client was employed.\u003c/p\u003e\n\u003cp\u003e4.2\u003cem\u003e \u003c/em\u003eChemistry\u003c/p\u003e\n\u003cp\u003eFor the synthesis of compounds, all the chemicals were procured from Spectrochem PrivateLimited, Sigma Aldrich, and Avra Synthesis Private Limited.All the reagents and solvents used for the synthesis of the proposed compounds were purified using standard laboratory techniques prior to use. Progress of the reactions was monitored using pre-coated silica gel GF\u003csub\u003e254\u003c/sub\u003e TLC plates, and spots were visualized under UV light at 254 or 365 nm. Different solvent systems, like hexane-ethyl acetate (7:3 and 6:4) and dichloromethane-methanol (9:1 v/v), were used as eluents. A Rota evaporator (BUCHI R-300) was used for removing the solvents during the workups. Chromatographic purification was performed by column chromatography using Silica gel #100-200. Melting points of the compounds were measured using a digital melting point apparatus (Veego VMP-D) and were uncorrected. Bruker FT-IR, model ALPHA-T (Germany) spectrophotometer was used for recording the IR spectra of individual compounds (wave numbers in cm\u003csup\u003e-1\u003c/sup\u003e) using ATR. Molecular weights of the synthesized compounds were determined using a Mass spectrophotometer, (Waters Acquity QDA). \u003csup\u003e1\u003c/sup\u003eNMR data was collected using an NMR instrument (Bruker 400 MHz) in CDCl\u003csub\u003e3\u003c/sub\u003e or DMSO-d\u003csub\u003e6\u003c/sub\u003e solvents (TMS used as internal standard). Purity and composition of the compounds were confirmed by elemental analysis using Thermo Fisher FLASH 2000 organic elemental analyser. The analysed compounds offered results within \u0026plusmn; 0.4 % of the theoretical values of carbon, hydrogen and nitrogen.\u003c/p\u003e\n\u003cp\u003e4.2.1\u003cem\u003e General Method for the Synthesis of Compounds (4 \u0026ndash; 6\u003c/em\u003e\u003cem\u003e):\u003c/em\u003e\u003cem\u003e \u003c/em\u003e(Method-A)\u003c/p\u003e\n\u003cp\u003eTo a solution of 1-Boc-piperazine (2.0 g, 10.74 mM) and glyoxylic acid monohydrate (0.98 g, 10.74 mM) in acetonitrile (20 mL), the corresponding boronic acid (10.74 mM) was added. The reaction mixture was stirred at 85 \u0026deg;C for 16 h, and progress of the reaction was monitored by TLC using (10 % methanol in dichloromethane). After the consumption of the starting materials, the solvent was removed under reduced pressure, and the residue was washed with hexane, and purified by column chromatography using silica gel as a stationary phase to afford the desired products (\u003cstrong\u003e4 - 6\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.2.1.1\u003cem\u003e \u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e2-(4-(tert-Butoxycarbonyl)piperazin-1-yl)-2-phenylacetic acid\u003c/em\u003e\u003c/strong\u003e(\u003cstrong\u003e4\u003c/strong\u003e): Prepared by \u003cstrong\u003eMethod A\u003c/strong\u003e using phenylboronic acid (1.3 g, 10.74 mM) (\u003cstrong\u003e2a\u003c/strong\u003e) to offer compound (\u003cstrong\u003e4\u003c/strong\u003e) as a white solid (3.22 g, 93.6 %), m.p. 180-183 \u003csup\u003eo\u003c/sup\u003eC; TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.50 (10 % Methanol in dichloromethane); IR: 3445, 2977, 2930, 1697, 1621, 1423, 1365, 1345, 1136, 1166, 1080, 965 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH-NMR: \u0026delta; 7.43-7.41 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.31-7.28 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 6.98 (s, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 4.16 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.52-3.37 (m, 4H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.73-2.66 (d, 4H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 1.47-1.45 (d, 9H, CH\u003csub\u003e3\u003c/sub\u003e); Mass (m/z): 321.2 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.2.1.2\u003cem\u003e \u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e2-(4-(tert-Butoxycarbonyl)piperazin-1-yl)-2-(4- fluorophenyl)\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003eacetic acid\u003c/em\u003e\u003c/strong\u003e (\u003cstrong\u003e5\u003c/strong\u003e): Prepared by \u003cstrong\u003eMethod A\u003c/strong\u003e using 4-fluorophenylboronic acid (1.5 g, 10.74 mM) (\u003cstrong\u003e2b\u003c/strong\u003e) to offer compound (\u003cstrong\u003e5\u003c/strong\u003e) as a white solid (3.45 g, 95 %), m.p. 176-178 \u003csup\u003eo\u003c/sup\u003eC; TLC(R\u003csub\u003ef \u003c/sub\u003e): 0.60 (10 % methanol in dichloromethane); IR: 3405, 2978, 2932, 1700, 1635, 1510, 1457, 1245, 1004, 757 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR \u0026delta; 7.45-7.42 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.21-7.17 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 4.02(s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.31-3.30 (d, 4H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.39-2.29 (m, 4H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 1.37 (s, 9H, C\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e); Mass (m/z): 339.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.2.1.3\u003cem\u003e \u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e2-(4-(tert-Butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e(6)\u003c/strong\u003e: Prepared by \u003cstrong\u003eMethod A\u003c/strong\u003e using 4-methoxyphenylboronic acid (1.63 g, 10.74 mM) (\u003cstrong\u003e2c\u003c/strong\u003e) to offer compound (\u003cstrong\u003e6\u003c/strong\u003e) as a white solid (3.42 g, 90.95 %), m.p. 135-138 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.55 (10 % Methanol in dichloromethane); IR: 3422, 2931, 1700, 1617, 1517, 1461, 1412, 1259, 1134, 1038, 966, 869 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR \u0026delta; 7.35-7.33 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 6.89-8.87 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 4.42 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.81 (s, 3H, OC\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e), 3.61 (s, 4H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.83 (s, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 1.44 (s, 9H, C\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e); Mass (m/z): 351.2 (M+1).\u003c/p\u003e\n\u003cp\u003e4.3.1\u003cem\u003e General method for acid-amine coupling for preparing compounds \u003c/em\u003e\u003cem\u003e(\u003c/em\u003e\u003cem\u003e16 - 42\u003c/em\u003e\u003cem\u003e)\u003c/em\u003e: (Method B)\u003c/p\u003e\n\u003cp\u003eTo a solution of the corresponding products (\u003cstrong\u003e4 - 6\u003c/strong\u003e) (1.0 g) in THF (10 mL), EDC.HCl (1 equiv), and HOBt (1 equiv) were added, and the reaction mixture was stirred at a temperature between 5-10 \u0026deg;C for a time period of 20 min. The corresponding aniline/substituted aniline (1 equiv) was added to the above solution followed by \u003cem\u003eN,N-\u003c/em\u003ediisopropylethylamine (3 equiv). Stirring was continued at RT for 16 h and THF was removed under reduced pressure. The resulting residue was extracted in DCM and washed with water; the organic layer was removed under reduced pressure to obtain the desired products (\u003cstrong\u003e16 - 42\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.1\u003cem\u003e tert-Butyl-4-(2-oxo-1-phenyl-2-(phenylamino)ethyl)piperazine-1-carboxylate\u003c/em\u003e (16):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-phenylacetic \u003cstrong\u003e(4)\u003c/strong\u003e (1.0 g, 3.12 mM), and aniline (0.29 g, 3.12 mM) to obtain compound (\u003cstrong\u003e16\u003c/strong\u003e) as white solid (0.92 g, 74.79 %) m.p. 88-90 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.40 (20 % Ethyl acetate in hexane), IR: 3501, 3259, 2862, 1676, 1601, 1559, 1447, 1249, 1171, 735 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.2\u003cem\u003e tert-Butyl-4-(2-oxo-1-phenyl-2-(o-tolylamino)ethyl)piperazine-1-carboxylate\u003c/em\u003e (17):\u003c/strong\u003e Prepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert-\u003c/em\u003ebutoxycarbonyl)piperazin-1-yl)-2-phenylacetic \u003cstrong\u003e(4)\u003c/strong\u003e (1.0 g, 3.12 mM), and 2-methylaniline (0.33 g, 3.12 mM)) to obtain compound (\u003cstrong\u003e17\u003c/strong\u003e) as brown solid (0.89 g, 69.53 %), m.p. 84-87 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.42 (20 % Ethyl acetate in hexane), IR: 3362, 2926, 1691, 1587, 1521, 1454, 1365, 1286, 1169, 1003 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.3\u003cem\u003e tert-Butyl-4-(2-oxo-1-phenyl-2-(p-tolylamino)ethyl)piperazine-1-carboxylate\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (18):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-phenylacetic \u003cstrong\u003e(4)\u003c/strong\u003e (1.0 g, 3.12 mM), and 4-methylaniline (0.33 g, 3.12 mM) to obtain compound (\u003cstrong\u003e18\u003c/strong\u003e) as brown solid (0.9 g, 70.31%), m.p. 80-82 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.44 (20 % Ethyl acetate in hexane), IR: 3326, 2974, 2857, 1706, 1668, 1597, 1452, 1364, 1287, 1170, 1018 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e\u003csub\u003e.\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.4\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-((2-methoxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (19): \u003c/strong\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-phenylacetic \u003cstrong\u003e(4)\u003c/strong\u003e (1.0 g, 3.12 mM), and 2-methoxyaniline (0.38 g, 3.12 mM) to obtain compound (\u003cstrong\u003e19\u003c/strong\u003e) as white solid (0.92 g, 69.17 %), m.p. 92-95 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.38 (20 % Ethyl acetate in hexane), IR: 3324, 2970, 2836, 1683, 1598, 1512, 1480, 1423, 1304, 1170, 1018 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.5\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-((4-methoxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e(20\u003c/strong\u003e\u003cstrong\u003e):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using\u003cem\u003e \u003c/em\u003e2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-phenylacetic \u003cstrong\u003e(4)\u003c/strong\u003e (1.0 g, 3.12 mM), and 4-methoxyaniline (0.38 g, 3.12 mM) to obtain compound (\u003cstrong\u003e20\u003c/strong\u003e) as white solid (0.94 g, 70.67 %), m.p. 98-100 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.38 (20 % Ethyl acetate in hexane), IR: 3307, 2974, 1692, 1601, 1514, 1456, 1165, 1170, 1129, 1033 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.6\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-((4-fluorophenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (21\u003c/strong\u003e\u003cstrong\u003e):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-phenylacetic \u003cstrong\u003e(4)\u003c/strong\u003e (1.0 g, 3.12 mM), and 4-fluoroaniline (0.34 g, 3.12 mM) to obtain the desired product (\u003cstrong\u003e21\u003c/strong\u003e) as brown solid (0.92 g, 71.32 %), m.p. 68-70 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.46 (20 % Ethyl acetate in hexane), IR: 3504, 2978, 1677, 1623, 1576, 1426, 1409, 1289, 1172, 1005 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.7\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-((4-chlorophenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (22\u003c/strong\u003e\u003cstrong\u003e):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-phenylacetic (\u003cstrong\u003e4\u003c/strong\u003e) (1.0 g, 3.12 mM), and 4-chloroaniline (0.39 g, 3.12 mM) to obtain compound (\u003cstrong\u003e22\u003c/strong\u003e) as brown solid (0.95 g, 70.89 %), m.p. 74-76 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (20 % Ethyl acetate in hexane), IR: 3319, 2976, 2857, 1704, 1677, 1592, 1400, 1635, 1244, 1170, 1001 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.8\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-((4-hydroxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (23\u003c/strong\u003e\u003cstrong\u003e):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-phenylacetic \u003cstrong\u003e(4)\u003c/strong\u003e (1.0 g, 3.12 mM), and 4-hydroxyaniline (0.34 g, 3.12 mM) was added to obtain compound (\u003cstrong\u003e23\u003c/strong\u003e) as brown solid (0.95 g, 74.21 %), m.p.104-107 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.32 (20 % Ethyl acetate in hexane), IR: 3295, 2975, 1690, 1607, 1514, 1247, 1169, 1132, 1005 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.9\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-(cyclohexylamino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (24):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-phenylacetic \u003cstrong\u003e(4)\u003c/strong\u003e (1.0 g, 3.12 mM), and cyclohexanamine (0.30 g, 3.12 mM) was added to obtain compound (\u003cstrong\u003e24\u003c/strong\u003e) as white solid (0.98 g, 78.4 %), m.p. 88-90 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.40 (20 % Ethyl acetate in hexane), IR: 3304, 2931, 2856, 1696, 1658, 1527, 1452, 1405, 1288, 1120, 1006 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.10\u003cem\u003e tert-Butyl-4-(1-(4-fluorophenyl)-2-oxo-2-(phenylamino)ethyl)piperazine-1-carboxylate\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (25):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid \u003cstrong\u003e(5)\u003c/strong\u003e (1.0 g, 2.95 mM), and aniline (0.27 g, 2.95 mM) was added to obtain compound (\u003cstrong\u003e25\u003c/strong\u003e) as white solid (0.91 g, 74.59 %) m.p. 82-84 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.52 (20 % Ethyl acetate in hexane), IR: 3308, 2976, 1690, 1600, 1507, 1440, 1366, 1247, 1169, 1027 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e. \u003cem\u003e \u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.11\u003cem\u003e tert-Butyl-4-(1-(4-fluorophenyl)-2-oxo-2-(o-tolylamino)ethyl)piperazine-1-carboxylate\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (26):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert-\u003c/em\u003ebutoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid \u003cstrong\u003e(5)\u003c/strong\u003e (1.0 g, 2.95 mM), and 2-methylaniline (0.31 g, 2.95 mM) was added to obtain compound (\u003cstrong\u003e26\u003c/strong\u003e) as brown solid (0.76 g, 60.31 %), m.p. 94-97 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (20 % Ethyl acetate in hexane), IR: 3309, 2924, 1693, 1601, 1510, 1421, 1285, 1366, 1168, 1001 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.12\u003cem\u003e tert-Butyl-4-(1-(4-fluorophenyl)-2-oxo-2-(p-tolylamino)ethyl)piperazine-1-carboxylate\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (27):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid \u003cstrong\u003e(5)\u003c/strong\u003e (1.0 g, 2.95 mM), and 4-methylaniline (0.31 g, 2.95 mM) was added to obtain compound (\u003cstrong\u003e27\u003c/strong\u003e) as brown solid (0.82 g, 65 %), m.p. 97-99 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.50 (20 % Ethyl acetate in hexane), IR: 3316, 2976, 1692, 1600, 1512, 1457, 1421, 1285, 1127, 1001 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e\u003csub\u003e.\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.13\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(1-(4-fluorophenyl)-2-((2-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate\u003c/strong\u003e (28\u003c/em\u003e\u003cem\u003e):\u003c/em\u003e Prepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid \u003cstrong\u003e(5)\u003c/strong\u003e (1.0 g, 2.95 mM), and 2-methoxyaniline (0.36 g, 2.95 mM) was added to obtain compound (\u003cstrong\u003e28\u003c/strong\u003e) as white solid (0.98 g, 69.5 %), m.p. 78-81 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.45 (20 % Ethyl acetate in hexane), IR: 3305, 2976, 2853, 1682, 1603, 1511, 1417, 1247, 1107, 1035, 1003 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.14\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(1-(4-fluorophenyl)-2-((4-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (29):\u003c/strong\u003e Prepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid \u003cstrong\u003e(5)\u003c/strong\u003e (1.0 g, 2.95 mM), and 4-methoxyaniline (0.36 g, 2.95 mM) was added to obtain compound (\u003cstrong\u003e29\u003c/strong\u003e) as brown solid (0.96 g, 68 %), m.p. 77-80 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.46 (20 % Ethyl acetate in hexane), IR: 3298, 2975, 1689, 1511, 1419, 1246, 1170, 1004 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.15\u003cem\u003e tert-Butyl-4-(1-(4-fluorophenyl)-2-((4-fluorophenyl)amino)-2-oxoethyl)piperazine-1-carboxylate\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (\u003c/strong\u003e\u003cstrong\u003e30):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid \u003cstrong\u003e(5)\u003c/strong\u003e (1.0 g, 2.95 mM), and 4-fluoroaniline (0.32 g, 2.95 mM) was added to obtain compound (\u003cstrong\u003e30\u003c/strong\u003e) as brown solid (0.89 g, 70 %), m.p. 63-66 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.54 (20 % Ethyl acetate in hexane), IR: 3296, 2976, 2930, 1692, 1509, 1423, 1403, 1286, 1170, 1004 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.16\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-((4-chlorophenyl)amino)-1-(4-fluorophenyl)-2-oxoethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (31):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid \u003cstrong\u003e(5)\u003c/strong\u003e (1.0 g, 2.95 mM), and 4-chloroaniline (0.37 g, 2.95 mM) was added to obtain compound (\u003cstrong\u003e31\u003c/strong\u003e) the desired product as white solid (0.94 g, 71.21 %), m.p. 70-73 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.56, IR: 3383, 2927, 1695, 1599, 1511, 1406, 1369, 1223, 1158, 1004 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e\u003csub\u003e.\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.17\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(1-(4-fluorophenyl)-2-((4-hydroxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (32\u003c/strong\u003e\u003cstrong\u003e):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid\u003cstrong\u003e (5)\u003c/strong\u003e (1.0 g, 2.95 mM), and 4-hydroxyaniline (0.32 g, 2.95 mM) was added to obtain compound (\u003cstrong\u003e32\u003c/strong\u003e) as brown solid (0.92 g, 73 %), m.p. 112-114 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.35 (20 % Ethyl acetate in hexane), IR: 3294, 2976, 1688, 1666, 1511, 1424, 1366, 12487, 1131, 1001 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e\u003csub\u003e.\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.18\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-(cyclohexylamino)-1-(4-fluorophenyl)-2-oxoethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (33):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4 fluorophenyl)acetic acid \u003cstrong\u003e(5)\u003c/strong\u003e (1.0 g, 2.95 mM), and cyclohexanamine (0.29 g, 2.95 mM) was added to obtain compound (\u003cstrong\u003e33\u003c/strong\u003e) as white solid (0.90 g, 72.58 %), m.p. 94-97 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.42 (20 % Ethyl acetate in hexane), IR: 3308, 2923, 2856, 1695, 1661, 1599, 1508, 1453, 1285, 1170, 1003 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.19\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003etert-Butyl-4-(1-(4-methoxyphenyl)-2-oxo-2-(phenylamino)ethyl)piperazine-1-carboxylate\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (34):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003cstrong\u003e (6)\u003c/strong\u003e (1.0 g, 2.85 mM) and aniline (0.26 g, 2.85 mM) was added to obtain compound (\u003cstrong\u003e34\u003c/strong\u003e) as brown solid (0.92 g, 76 %), m.p. 112-115 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.58 (20 % Ethyl acetate in hexane), IR: 3307, 2974, 1692, 1601, 1511, 1441, 1247, 1174, 754 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.20\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(1-(4-methoxyphenyl)-2-oxo-2-(o-tolylamino)ethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (35\u003c/strong\u003e\u003cstrong\u003e):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003cstrong\u003e (6)\u003c/strong\u003e (1.0 g, 2.85 mM), and 2-methylaniline (0.30 g, 2.85 mM) was added to obtain compound (\u003cstrong\u003e35\u003c/strong\u003e) as brown solid (0.86 g, 68.8 %), m.p. 107-110 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.60 (20 % Ethyl acetate in hexane), IR: 3356, 2975, 1692, 1607, 1511, 1454, 1247, 1172, 1002 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.21\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(1-(4-methoxyphenyl)-2-oxo-2-(p-tolylamino)ethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (36):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using\u003cem\u003e \u003c/em\u003e2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003cstrong\u003e (6)\u003c/strong\u003e (1.0 g, 2.85 mM), and 4-methylaniline (0.30 g, 2.85 mM) was added to obtain compound (\u003cstrong\u003e36\u003c/strong\u003e) as white solid (0.70 g, 70.4 %), m.p. 104-105 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.60 (20 % Ethyl acetate in hexane), IR: 3303, 2930, 2855, 1688, 1643, 1509, 1242, 1168, 1120 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.22\u003cem\u003e tert-Butyl-4-(1-(4-methoxyphenyl)-2-((2-methoxyphenyl)amino)-2-oxoethyl)- piperazine-1-carboxylate\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (37):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003cstrong\u003e (6)\u003c/strong\u003e (1.0 g, 2.85 mM), and 2-methoxyaniline (0.35 g, 2.85mM) was added to obtain compound \u003cstrong\u003e(37\u003c/strong\u003e) as white solid (0.89 g, 68.46 %), m.p. 98-101 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.54 (20 % Ethyl acetate in hexane), IR: 3333, 2929, 2852, 1689, 1608, 1510, 1242, 1168, 1026 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003cem\u003e \u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.23\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(1-(4-methoxyphenyl)-2-((4-methoxyphenyl)amino)-2-oxoethyl)piperazine -1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (38):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003cstrong\u003e (6)\u003c/strong\u003e (1.0 g, 2.85 mM), and 4-methoxyaniline (0.35 g, 2.85 mM) was added to obtain compound (\u003cstrong\u003e38\u003c/strong\u003e) as white solid (0.95, 73 %), m.p. 95-97 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.54 (20 % Ethyl acetate in hexane), IR:3334, 2929, 2852, 1688, 1645, 1509, 1403, 1242, 1168, 1027 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.24\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-((4-fluorophenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (39\u003c/strong\u003e\u003cstrong\u003e):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003cstrong\u003e (6)\u003c/strong\u003e (1.0 g, 2.85 mM), and 4-fluoroaniline (0.31 g, 2.85 mM) was added to obtain compound (\u003cstrong\u003e39\u003c/strong\u003e) as white solid (0.92 g, 73 %), m.p. 94-95 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.56 (20 % Ethyl acetate in hexane), IR: 3305, 2974, 1690, 1611, 1511, 1458, 1248, 1172, 1033 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.25\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-((4-chlorophenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate (4\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e\u003cem\u003e0):\u003c/em\u003e\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003cstrong\u003e (6)\u003c/strong\u003e (1.0 g, 2.85 mM), and 4-chloroaniline (0.36 g, 2.85 mM) was added to obtain compound (\u003cstrong\u003e40\u003c/strong\u003e), the desired product as brown solid (0.98 g, 74.8 %), m.p. 108-110 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.62 (20 % Ethyl acetate in hexane), IR: 3428, 2975, 1685, 1594, 1511, 1412, 1247, 1171,1008 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.26\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert-Butyl-4-(2-((4-hydroxyphenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)- piperazine-1-carboxylate (41):\u003c/strong\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003cstrong\u003e (6)\u003c/strong\u003e (1.0 g, 2.85 mM), and 4-hydroxyaniline (0.31 g, 2.85 mM) was added to obtain compound (\u003cstrong\u003e41\u003c/strong\u003e), the desired product as brown solid (0.93 g, 73.8 %), m.p. 120-122 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.40 (20 % Ethyl acetate in hexane), IR: 3333, 2929, 2852, 1690, 1645, 1510, 1403, 1242, 1168, 1027 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3.1.27\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003etert\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e-Butyl-4-(2-(cyclohexylamino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate (42\u003c/strong\u003e\u003cstrong\u003e):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003ePrepared by \u003cstrong\u003eMethod B\u003c/strong\u003e using 2-(4-(\u003cem\u003etert\u003c/em\u003e-butoxycarbonyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetic acid\u003cstrong\u003e (6)\u003c/strong\u003e (1.0 g, 2.85 mM), and cyclohexylamine (0.28 g, 2.85 mM) was added to obtain compound (\u003cstrong\u003e42\u003c/strong\u003e), the desired product as white solid (0.90 g, 73.1 %), m.p. 90-93 \u003csup\u003eo\u003c/sup\u003eC, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.45 (20 % Ethyl acetate in hexane), IR: 3327, 2930, 2854, 1689, 1643, 1509, 1420, 1242, 1168, 1117 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e4.4.1\u003cem\u003e General Method for Boc-deprotection: (43-69\u003c/em\u003e\u003cem\u003e)\u003c/em\u003e: (Method C)\u003c/p\u003e\n\u003cp\u003eTo a solution of the corresponding products (\u003cstrong\u003e16 - 42\u003c/strong\u003e) in DCM (7.5 mL), dioxane-HCl (7.5 mL) (dioxane saturated with hydrogen chloride gas) was added and stirred at 25 \u003csup\u003eo\u003c/sup\u003eC for 3 h. The reaction was monitored on TLC, after the completion of the reaction, solvent was removed under reduced pressure to obtain sticky Products (\u003cstrong\u003e43 - 69\u003c/strong\u003e) which were used as such for the next step.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.1\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003eN,2-Diphenyl-2-(piperazin-1-yl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (43):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl-4-(2-oxo-1-phenyl-2-(phenylamino)ethyl)piperazine-1-carboxylate (\u003cstrong\u003e16\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM) through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e43\u003c/strong\u003e) (0.54 g, 96.42 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.51 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.2\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-Phenyl-2-(piperazin-1-yl)-N-(o-tolyl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (44):\u003c/strong\u003e \u003cem\u003etert\u003c/em\u003e-Butyl 4-(2-oxo-1-phenyl-2-(\u003cem\u003eo\u003c/em\u003e-tolylamino)ethyl)piperazine-1-carboxylate (\u003cstrong\u003e17\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM)\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e44\u003c/strong\u003e) (0.53 g, 94.64 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.\u003c/strong\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-Phenyl-2-(piperazin-1-yl)-N-(p-tolyl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (45):\u003c/strong\u003e \u003cem\u003etert\u003c/em\u003e-Butyl 4-(2-oxo-1-phenyl-2-(\u003cem\u003ep\u003c/em\u003e-tolylamino)ethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e18\u003c/strong\u003e) (0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003ethrough \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e45\u003c/strong\u003e) (0.52 g, 92.85 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.46 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.4\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-Methoxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (46):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(2-((2-methoxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e19\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e46\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.53 g, 94.64 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.5\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(4-Methoxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (47):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(2-((4-methoxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate (\u003cstrong\u003e20\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e47\u003c/strong\u003e) (0.56 g, 98.24 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.42 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.6\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(4-Fluorophenyl)-2-phenyl-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (48):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(2-((4-fluorophenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate (\u003cstrong\u003e21\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e48\u003c/strong\u003e) (0.54 g, 94.73 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.43 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.7\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(4-Chlorophenyl)-2-phenyl-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (49):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(2-((4-chlorophenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e22\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e49\u003c/strong\u003e) (0.55 g, 98.21 %) which was further used for the final reaction. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.47 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.8\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(4-Hydroxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (50):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-butyl 4-(2-((4-hydroxyphenyl)amino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate (\u003cstrong\u003e23\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e50\u003c/strong\u003e) (0.54 g, 94.73 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.9\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-Cyclohexyl-2-phenyl-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (51):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-butyl 4-(2-(cyclohexylamino)-2-oxo-1-phenylethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e24\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e51\u003c/strong\u003e) (0.55 g, 98.21 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.49 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.10\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-Fluorophenyl)-N-phenyl-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (52): \u003c/strong\u003e\u003cem\u003etert\u003c/em\u003e-Butyl 4-(1-(4-fluorophenyl)-2-oxo-2\u003cem\u003e-\u003c/em\u003e(phenylamino)ethyl)piperazine-1-carboxylate (\u003cstrong\u003e25\u003c/strong\u003e) (0.75 g, 1.76 mM through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e52\u003c/strong\u003e) (0.54 g, 94.73 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.50 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.11\u003cem\u003e 2-(4-Fluorophenyl)-2-(piperazin-1-yl)-N-(o-tolyl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (53):\u003c/strong\u003e \u003cem\u003etert\u003c/em\u003e-Butyl 4-(1-(4-fluorophenyl)-2-oxo-2-(\u003cem\u003eo\u003c/em\u003e-tolylamino)ethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e26\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e53\u003c/strong\u003e) (0.53 g, 92.98 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.12\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-Fluorophenyl)-2-(piperazin-1-yl)-N-(p-tolyl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (54\u003c/strong\u003e\u003cem\u003e): tert\u003c/em\u003e-Butyl 4-(1-(4-fluorophenyl)-2-oxo-2-(\u003cem\u003ep\u003c/em\u003e-tolylamino)ethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e27\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e54\u003c/strong\u003e) (0.55 g, 96.49 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.13\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-Fluorophenyl)-N-(2-methoxyphenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (55):\u003c/strong\u003e \u003cem\u003etert\u003c/em\u003e-Butyl 4-(1-(4-fluorophenyl)-2-((2-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e28\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e55\u003c/strong\u003e) (0.56 g, 96.55 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.44 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.14\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-Fluorophenyl)-N-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (56):\u003c/strong\u003e \u003cem\u003etert\u003c/em\u003e-Butyl 4-(1-(4-fluorophenyl)-2-((4-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e29\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e (0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e56\u003c/strong\u003e) (0.55 g, 94.82 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.44 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.15\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN,2-Bis(4-fluorophenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (57):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(1-(4-fluorophenyl)-2-((4-fluorophenyl)amino)-2-oxoethyl)piperazine-1-carboxylate (\u003cstrong\u003e30\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e57\u003c/strong\u003e) (0.56 g, 98.24 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.45 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.16\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(4-Chlorophenyl)-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (58):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(2-((4-chlorophenyl)amino)-1-(4-fluorophenyl)-2-oxoethyl)piperazine-1-carboxylate (\u003cstrong\u003e31\u003c/strong\u003e\u003cem\u003e) \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e in DCM (7.5 mL), through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e58\u003c/strong\u003e) (0.52 g, 89.65 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.17\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-Fluorophenyl)-N-(4-hydroxyphenyl)-2-(piperazin-1-yl)acetamide \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e(59):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(1-(4-fluorophenyl)-2-((4-hydroxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e32\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e59\u003c/strong\u003e) (0.54 g, 94.73 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.47 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.18\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-Cyclohexyl-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (60):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(2-(cyclohexylamino)-1-(4-fluorophenyl)-2-oxoethyl)piperazine-1-carboxylate (\u003cstrong\u003e33\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e60)\u003c/strong\u003e (0.56 g, 98.24 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.52 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.19\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-Methoxyphenyl)-N-phenyl-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (61):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(1-(4-methoxyphenyl)-2-oxo-2-(phenylamino)ethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e34\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e61\u003c/strong\u003e) (0.52 g, 94.73%). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.45 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.20\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-Methoxyphenyl)-2-(piperazin-1-yl)-N-(o-tolyl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (62):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(1-(4-methoxyphenyl)-2-oxo-2-(o-tolylamino)ethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e35\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e in DCM (7.5 mL), through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e62\u003c/strong\u003e) (0.53 g, 91.37 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.21\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-Methoxyphenyl)-2-(piperazin-1-yl)-N-(p-tolyl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (63):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(1-(4-methoxyphenyl)-2-oxo-2-(p-tolylamino)ethyl)piperazine-1-carboxylate (\u003cstrong\u003e36\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e in DCM (7.5 mL), through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e63\u003c/strong\u003e) (0.56 g, 96.55 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.22\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(2-Methoxyphenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (64):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(1-(4-methoxyphenyl)-2-((2-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate (\u003cstrong\u003e37\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e64\u003c/strong\u003e) (0.56 g, 96.55 %) which was further processed for the final reaction. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.42 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.23\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN,2-Bis(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e(65):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(1-(4-methoxyphenyl)-2-((4-methoxyphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e38\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e65\u003c/strong\u003e) (0.54 g, 93.10 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.42 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.24\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(4-Fluorophenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (66):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(2-((4-fluorophenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate (\u003cstrong\u003e39\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e66\u003c/strong\u003e) (0.54 g, 96.42 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.43 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.25\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(4-Chlorophenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (67):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(2-((4-chlorophenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate (\u003cstrong\u003e40\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e67\u003c/strong\u003e) (0.57 g, 96.61 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.26\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-(4-Hydroxyphenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (68):\u003c/strong\u003e \u003cem\u003etert\u003c/em\u003e-Butyl 4-(2-((4-hydroxyphenyl)amino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate (\u003cstrong\u003e41\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e68\u003c/strong\u003e) (0.52 g, 89.85 %). TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (70 % Ethyl acetate in hexane).\u003cem\u003e \u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.4.1.27\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-Cyclohexyl-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (69):\u003c/strong\u003e\u003cem\u003e tert\u003c/em\u003e-Butyl 4-(2-(cyclohexylamino)-1-(4-methoxyphenyl)-2-oxoethyl)piperazine-1-carboxylate (\u003cstrong\u003e42\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.75 g, 1.76 mM),\u003cem\u003e \u003c/em\u003e through \u003cstrong\u003eMethod C\u003c/strong\u003e offered the product (\u003cstrong\u003e69\u003c/strong\u003e) (0.56 g, 98.24 %) which was further processed for final reaction. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.36 (70 % Ethyl acetate in hexane).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.5.1\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e5-Chloromethylquinolin-8-ol\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e(70):\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA mixture of 8-hydroxyquinoline (10.0 g, 68 mM), concentrated hydrochloric acid (13 mL) and formalin \u003cstrong\u003e(\u003c/strong\u003e37 %formaldehyde and 12 % methanol, 12 mL, 399 mM)) was treated with hydrogen chloride gas and stirred for 3 h. The yellow solid obtained was collected on a filter paper, washed three times in acetone, and dried under vacuum to afford 5-chloromethyl-8-hydroxyquinoline (\u003cstrong\u003e70\u003c/strong\u003e) as a yellow solid hydrochloride salt, m.p. \u0026gt;260 \u003csup\u003eo\u003c/sup\u003eC, Reported \u0026gt;260 \u003csup\u003eo\u003c/sup\u003eC [42].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1 \u003cem\u003eGeneral procedure for the synthesis of the target compounds\u003c/em\u003e \u003c/strong\u003e\u003cstrong\u003e(71 \u0026ndash; 79, 80 \u0026ndash; 88 and 89 - 97): (Method D)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo a solution of the corresponding products (\u003cstrong\u003e43 - 69\u003c/strong\u003e) (1.0 equiv) in DMSO (7 mL), triethylamine (5.0 equiv) was added and the reaction mixture was stirred at 25 \u003csup\u003eo\u003c/sup\u003eC for 10 min followed by the addition of 5-chloromethyl-8-hydroxyquinoline hydrochloride (\u003cstrong\u003e70\u003c/strong\u003e) (1.0 equiv) portion-wise. The reaction mixture was stirred at 100 \u003csup\u003eo\u003c/sup\u003eC for 16 h, and the progress of the reaction was monitored by TLC using (80 % ethyl acetate in hexane) After the consumption of the starting materials, the reaction mixture was poured into ice-cold water to obtain solid products (\u003cstrong\u003e71 - 97\u003c/strong\u003e) which were filtered, dried and further purified by column chromatography using #100-200 silica gel as stationary phase and ethyl acetate:hexane as mobile phase to afford the desired pure products (\u003cstrong\u003e71 - 97\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.1\u003cem\u003e \u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N,2-diphenylacetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (71):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing \u003cem\u003eN\u003c/em\u003e,2-diphenyl-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e43\u003c/strong\u003e) (0.5 g, 1.69 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e71\u003c/strong\u003e) was obtained, m.p. 72-75 \u0026deg;C. TLC (Rf): 0.54 (80 % Ethyl acetate in hexane); IR: 3314, 2931, 2816, 1686, 1599, 1503, 1474, 1440, 1371, 1312, 1271, 1231, 1076, 827 cm\u003csup\u003e-1\u003c/sup\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.25 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 8.79-8.78 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.63-8.61 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.61-7.59 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.47-7.44 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.38-7.36 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.33 (s, 5H, Ar\u003cem\u003eH\u003c/em\u003e), 7.28 (s, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.15-7.11 (t, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.08-7.06 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 3.98 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.83 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.63-2.50 (m, 8H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e28\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2 \u003c/sub\u003erequires: C, 74.31; H, 6.24; N, 12.38; found C, 74.58; H, 6.41; N, 12.10; LC-MS (m/z): 453.2 (M+1); Purity 98.20 %.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.2\u003cem\u003e \u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl-N-(o-tolyl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (72):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e \u003c/em\u003e2-phenyl-2-(piperazin-1-yl)-N-(o-tolyl)acetamide (\u003cstrong\u003e44\u003c/strong\u003e\u003cem\u003e) \u003c/em\u003e (0.5 g, 1.61 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e72\u003c/strong\u003e) was obtained as a yellowish white solid (0.59 g, 78.66 %), which was further purified by column chromatography using #100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 110-112 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.52 (80 % Ethyl acetate in hexane); IR: 3338, 2923, 2812, 2766, 1669, 1596, 1505, 1475, 1229, 1136, 1007, 699 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR; \u0026delta; 9.71-9.61 (m, 2H, N\u003cem\u003eH, \u003c/em\u003eO\u003cem\u003eH\u003c/em\u003e), 8.85-8.79 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.64-8.52 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.57-6.98 (m, 11H, Ar\u003cem\u003eH\u003c/em\u003e), 4.09 (s, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 2.69- 2.56 (bs, 3H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.41-2.35 (bs, 5H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.18 (s, 3H, C\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e30\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e requires: C, 74.65; H, 6.48; N, 12.01; found C, 74.44; H, 6.56; N, 11.83; Mass (m/z): 467.4 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.3\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-((8-\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e\u003cem\u003eHydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl-N-(p-tolyl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (73):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing 2-phenyl-2-(piperazin-1-yl)-\u003cem\u003eN\u003c/em\u003e-(\u003cem\u003ep\u003c/em\u003e-tolyl)acetamide (\u003cstrong\u003e45\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e (0.5 g, 1.61 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e73\u003c/strong\u003e) was obtained as a greenish white solid (0.57 g, 76 %), which was further purified by column chromatography using #100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 165-168 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.53 (80 % Ethyl acetate in hexane); IR: 3329, 2817, 1658, 1595, 1472, 1363, 1230, 1133, 1004, 705 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.16 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 8.79-8.78 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.63-8.61 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.49-7.44 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.34-7.32 (d, 6H, Ar\u003cem\u003eH\u003c/em\u003e), 7.17-7.14 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.08-7.06 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 3.97 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.84 (s, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.53 (d\u003cstrong\u003e,\u003c/strong\u003e 8H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.34 (s, 3H, C\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e30\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2 \u003c/sub\u003erequires: C, 74.65; H, 6.48; N, 12.01; found C, 74.48; H, 6.65; N, 12.22; LC-MS (m/z): 467.5 (M+1); Purity 95.58 %.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.4\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(2-methoxyphenyl)-2-phenyl- acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (74):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-(2-methoxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e46\u003c/strong\u003e) (0.5 g, 1.53 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e74\u003c/strong\u003e) was obtained as a light orange solid (0.57 g, 76 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 82-85 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.49 (80 % Ethyl acetate in hexane); IR: 3327, 2936, 2814, 1738, 1598, 1521, 1460, 1230, 1025, 787 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.97 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.72 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.83-8.82 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.60-8.58 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 8.11- 8.09 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.56-7.53 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.34 (d, 4H, Ar\u003cem\u003eH\u003c/em\u003e), 7.28(d, 2H, Ar\u003cem\u003eH\u003c/em\u003e),\u003cem\u003e \u003c/em\u003e7.08-7.07 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 6.99-6.97 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.92-6.84 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 4.21 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.94 (s, 3H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 3.79-3.34 (m, 2H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 2.47-2.20 (m, 8H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e30\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e requires: C, 72.18; H, 6.27; N, 11.61; found C, 71.81; H, 6.54; N, 11.43; Mass (m/z): 483.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.5\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-((\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e\u003cem\u003e8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(4-methoxyphenyl)-2-phenyl- acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (75):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-(4-methoxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e47\u003c/strong\u003e) (0.5 g, 1.53 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e75\u003c/strong\u003e) was obtained as a yellowish white solid (0.57 g, 77 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 175-178 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.49 (80 % Ethyl acetate in hexane); IR: 3332, 2955, 2808, 1664, 1520, 1473, 1248, 1135, 1030, 821 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR; \u0026delta; 9.92 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.72 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.85 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.63-8.61 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.59-7.57 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.51-7.46 (m, 4H, Ar\u003cem\u003eH\u003c/em\u003e), 7.36-7.26 (m, 4H, Ar\u003cem\u003eH\u003c/em\u003e), 6.99-6.97 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.88-8.84 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 3.94 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 3.70 (s, 3H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 2.35 (bs, 8H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e30\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e requires: C, 72.18; H, 6.27; N, 11.61; found C, 71.88; H, 6.55; N, 11.31; Mass (m/z): 483.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.6\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003eN-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl- acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (76):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-(4-fluorophenyl)-2-phenyl-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e48\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.59 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e76\u003c/strong\u003e) was obtained as a yellowish white solid (0.58 g, 77.33 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 89-90\u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.51 (80 % Ethyl acetate in hexane); IR: 3296, 2822, 1669, 1509, 1406, 1372, 1211, 1006, 835 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 10.22- 10.11 (d, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.71 (bs, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.86-8.85 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.64-8.62 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.77- 7.59 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.50-7.48 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.37-7.36 (m, 4H, Ar\u003cem\u003eH\u003c/em\u003e), 7.15-7.13 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.01-6.99 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 3.80 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.41 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.69 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.43- 2.47 (d, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e27\u003c/sub\u003eFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2 \u003c/sub\u003erequires: C, 71.47; H, 5.78; N, 11.91; found C, 71.16; H, 5.96; N, 11.72; Mass (m/z): 471.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.7\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003eN-(4-Chlorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl- acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (77):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing \u003cem\u003eN\u003c/em\u003e-(4-chlorophenyl)-2-phenyl-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e49\u003c/strong\u003e) (0.5 g, 1.51 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e77\u003c/strong\u003e) was obtained as a yellowish white solid (0.58 g, 77.33 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 89-90\u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.51 (80 % Ethyl acetate in hexane); IR: 3296, 2822, 1669, 1509, 1406, 1372, 1211, 1006, 835 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 10.22- 10.11 (d, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.71 (bs, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.86-8.85 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.64-8.62 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.77- 7.59 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.50-7.48 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.37-7.36 (m, 4H, Ar\u003cem\u003eH\u003c/em\u003e), 7.15-7.13 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.01-6.99 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 3.80 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.41 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.69 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.43- 2.47 (d, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e27\u003c/sub\u003eClN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e requires: C, 69.06; H, 5.59; N, 11.50; found C, 68.78; H, 5.87; N, 11.34; Mass (m/z): 471.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.8\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003eN-(4-Hydroxyphenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenyl- acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (78):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing \u003cem\u003eN\u003c/em\u003e-(4-hydroxyphenyl)-2-phenyl-2-(piperazin-1-yl)acetamide\u003cem\u003e \u003c/em\u003e(\u003cstrong\u003e50\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.44 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e78\u003c/strong\u003e) was obtained as a brown solid (0.59 g, 79.72 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 155-158 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.52 (80 % Ethyl acetate in hexane); IR: 3331, 2928, 2813, 1677, 1592, 1474, 1398, 1270, 1134, 1005 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 10.19 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.71 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.85- 8.84 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.63-8.64 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.65-7.63 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.57-7.56 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.49-7.47 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.37-7.32 (m, 6H, Ar\u003cem\u003eH\u003c/em\u003e), 7.0-6.99 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 3.99 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.47-2.36 (bs, 8H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e28\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e requires: C, 71.78; H, 6.02; N, 11.96; found C, 71.56; H, 6.35; N, 11.74; Mass (m/z): 487.3 (M\u003csup\u003e+\u003c/sup\u003e). 488.3 (M+1), 489.2 (M+2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.\u003c/strong\u003e\u003cstrong\u003e9\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-Cyclohexyl-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-phenylacetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (79):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-cyclohexyl-2-phenyl-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e51\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.44 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e79\u003c/strong\u003e) was obtained as a greenish-white solid (0.63 g, 82.89 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. \u0026gt;220 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.43 (80 % Ethyl acetate in hexane); IR: 3320, 2924, 2818, 1662, 1514, 1474, 1371, 1231, 1004 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.79 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 9.71 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 9.20 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 8.87-8.84 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.63-8.57 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.58-7.55 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.45-7.46 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.36-7.25 (m, 6H, Ar\u003cem\u003eH\u003c/em\u003e), 6.99-6.97 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.67-6.65 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 3.91 (s, 1H), 3.76 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.54 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 2.50-2.33 (ds, 7H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e);\u003csup\u003e 13\u003c/sup\u003eC NMR \u0026delta;: 169.01, 147.66, 138.80, 137.52, 133.72, 128.78, 128.51, 128.00, 127,80, 127.44, 121.32, 109.87, 74.12, 59.53, 52.55, 50.67, 47.15, 40.41, 32.32, 32.04, 25.11, 24.43. C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e34\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2 \u003c/sub\u003erequires: C, 73.33; H, 7.47; N, 12.22; found C, 73.05; H, 7.78; N, 12.04; Mass (m/z): 469.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.10\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-phenyl- acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (80):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e \u003c/em\u003e2-(4-fluorophenyl)-\u003cem\u003eN\u003c/em\u003e-phenyl-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e52\u003c/strong\u003e) (0.5 g, 1.59 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e80\u003c/strong\u003e) was obtained as a greenish white solid (0.56 g, 74.66 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 74-77 \u0026deg;C, TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (80 % Ethyl acetate in hexane), IR: 3305, 3056, 2931, 2815, 1685, 1507, 1439, 1353, 1246, 1176, 1133, 1030 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 10.08 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.72 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.84 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.62 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.60-7.57 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.55-7.53 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.35-7.24 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.18 (t, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.05 (t, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.98 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 4.02 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.55-2.25 (m, 8H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e);\u003csup\u003e 13\u003c/sup\u003eC NMR \u0026delta;: 168.95, 162.92, 160.50, 152.75, 147.69, 138.78, 133.66, 133.19, 130.55, 128.75, 127.79, 123.97, 123.58, 121.33, 119.53, 115.15, 114.94, 109.88, 73.69, 59.48, 52.48, 50.63. C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e27\u003c/sub\u003eFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2 \u003c/sub\u003erequires: C, 71.47; H, 5.78; N, 11.91; found C, 71.15; H, 5.95; N, 11.73; Mass (m/z): 471.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.11\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(o-tolyl)- acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (81):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing \u003cem\u003e \u003c/em\u003e2-(4-fluorophenyl)-2-(piperazin-1-yl)-\u003cem\u003eN\u003c/em\u003e-(\u003cem\u003eo\u003c/em\u003e-tolyl)acetamide (\u003cstrong\u003e53\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.53 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e81\u003c/strong\u003e) was obtained as a greenish-white solid (0.57 g, 77 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 86-89 \u0026deg;C. TLC (Rf): 0.51 (80 % Ethyl acetate in hexane); IR: 3312, 2931, 1675, 1508, 1439, 1350, 1245, 1133, 1028 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; 1H NMR: \u0026delta; 9.70 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 9.61 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 8.85-8.83 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.63-8.60 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.58-7.55 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.49-7.46 (m, 4H, Ar\u003cem\u003eH\u003c/em\u003e), 7.34-7.32 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.21-7.19 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.17 (s, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.15-7.13 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.09-7.05 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 6.99-6.97 (d, 1H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 4.12(s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.81-3.74 (m, 3H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e ), 2.51-2.38 (bs, 4H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.16 (s, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e29\u003c/sub\u003eFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2 \u003c/sub\u003erequires: C, 71.88; H, 6.03; N, 11.56; found C, 71.55; H, 6.46; N, 11.27; Mass (m/z): 485.4 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.\u003c/strong\u003e\u003cstrong\u003e12\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(p-tolyl)- acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (82):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing \u003cem\u003e \u003c/em\u003e2-(4-fluorophenyl)-2-(piperazin-1-yl)-\u003cem\u003eN\u003c/em\u003e-(\u003cem\u003ep\u003c/em\u003e-tolyl)acetamide (\u003cstrong\u003e54\u003c/strong\u003e) (0.5 g, 1.53 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e82\u003c/strong\u003e) was obtained as a yellowish white solid (0.58 g, 78.37 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 103-106 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.53 (80 % Ethyl acetate in hexane); IR: 3314, 2924, 2816, 1689, 1599, 1507, 1461, 1432, 1225 1115, 788, 749 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR \u0026delta; 9.96 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.67 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.85-8.84 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.64-8.61 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.58- 7.55 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.52-7.48 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.47- 7.45 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.33-7.32 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.20-7.15 (t, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.10-7.08 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.00-6.98 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 4.00 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.54-2.35 (bs, 8H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.24 (s, 3H, C\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e29\u003c/sub\u003eFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e requires; C, 71.88; H, 6.03; N, 11.56; found C, 71.76; H, 6.37; N, 11.23; Mass (m/z): 485.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.13\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(2-methoxyphenyl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (83):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e \u003c/em\u003e2-(4-fluorophenyl)-\u003cem\u003eN\u003c/em\u003e-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e55\u003c/strong\u003e) (0.5 g, 1.45 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e83\u003c/strong\u003e) was obtained as a yellowish white solid (0.56 g, 76.71 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p.140-143 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.51 (80 % Ethyl acetate in hexane); IR: 3312, 2927, 2816, 1691, 1599, 1523, 1506, 1477, 1461, 1225, 1169, 1026, 789, 750 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.97 (s, 1H, NH), 9.69 (s, 1H, OH), 8.84-8.83 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.61-8.59 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.10-8.08 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.57-7.54 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.35-7.32 (t, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.21-7.16 (t, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.10-7.08 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.00-6.98 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.94-6.90 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 4.30 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.94 (s, 3H, OC\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e), 3.80 (s, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.68 (bs, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.37 (bs, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e29\u003c/sub\u003eFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3 \u003c/sub\u003erequires: C, 69.58; H, 5.84; F, 3.80; N, 11.19; found C, 69.36; H, 6.16; N, 10.91; LC-MS (m/z): 501.5 (M+1); Purity 97.11 %.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.14\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(4-methoxyphenyl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (84):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e,2-bis(4-fluorophenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e56\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.45 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (84) was obtained as a yellowish white solid (0.54 g, 73.93 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 86-88 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.52 (80 % Ethyl acetate in hexane); IR: 3312, 2933, 2817, 1682, 1603, 1509, 1474, 1412, 1230, 1371, 1133, 1033, 1005, 828, 787\u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.92 (s, 1H, NH), 9.67 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.85-8.84 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.64-8.61 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.59-7.55 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.52-7.48 (m, 4H, Ar\u003cem\u003eH\u003c/em\u003e), 7.34-7.32 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.20-7.15 (t, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.0-6.98 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.88-6.85 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 3.97 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 3.71 (s, 3H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 2.69 (d, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.34 (s, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e29\u003c/sub\u003eFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3 \u003c/sub\u003erequires: C, 69.58; H, 5.84; N, 11.19; found C, 69.35; H, 5.96; N, 11.02; LC-MS (m/z): 501.4 (M+1); Purity 94.50 %.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.15\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003eN,2-bis(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)- acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (85):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-(4-chlorophenyl)-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e57\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.50 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e85\u003c/strong\u003e) was obtained as a greenish white solid (0.57 g, 79.16 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 85-88 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (80 % Ethyl acetate in hexane); IR: 3391, 2923, 1693, 1507, 1474, 1271, 1227, 1005 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 10.12 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.68 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.85-8.84 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.63-8.61 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.63-7.59 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.57 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.53-7.49 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.33-7.31 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.20-7.16 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e),7.15-7.10 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e) 7.00-6.98 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 4.00 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.47- 2.33 (bs, 8H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e26\u003c/sub\u003eF2N\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2 \u003c/sub\u003erequires: C, 68.84; H, 5.36; F, 7.78; N, 11.47; found C, 68.68; H, 5.57; N, 11.15; LC-MS (m/z): 489.4 (M+1); Purity 98.68 %.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.16\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003eN-(4-Chlorophenyl)-2-(4-fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)- piperazin-1-yl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (86)\u003c/strong\u003e\u003cem\u003e: \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-(4-chlorophenyl)-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e58\u003c/strong\u003e) \u003cem\u003e \u003c/em\u003e(0.5 g, 1.45 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e73\u003c/strong\u003e) was obtained as a greenish white solid (0.57 g, 79.16 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 80-83 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.46 (80 % Ethyl acetate in hexane); IR: 3314, 2924, 2819, 1693, 1598, 1505, 1399, 1271, 1228, 1006, 828 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; 1H NMR: \u0026delta; 10.21 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 8.85-8.83 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.64-8.61 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.66-7.62 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.59-7.56 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.53-7.49 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.36-7.32 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.21-7.16 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.00-6.99 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 4.02 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.71-2.34 (bm, 8H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e26\u003c/sub\u003eClFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2 \u003c/sub\u003erequires: C, 66.60; H, 5.19; N, 11.09; found C, 66.98; H, 5.49; N, 10.87; Mass (m/z): 505.3 (M+), 507.2 (M+2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.17\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-(4-Fluorophenyl)-N-(4-hydroxyphenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)- piperazin-1-yl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (87):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e \u003c/em\u003e2-(4-fluorophenyl)-\u003cem\u003eN\u003c/em\u003e-(4-hydroxyphenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e59\u003c/strong\u003e) (0.5 g, 1.52 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e87\u003c/strong\u003e) was obtained as a obtain brown solid (0.56 g, 75.67 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 80-82 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.40 (80 % Ethyl acetate in hexane); IR: 3270, 2923, 2816, 1664, 1506, 1474, 1226, 1016, 832 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.81 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.68 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 9.19 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.85-8.84 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.63-8.61 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.59-7.55 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.51-7.48 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.36-7.31 (t, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.19-7.15 (t, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 6.99-6.98 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.68-6.65 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 3.95 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.68 (s, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.33 (s, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e27\u003c/sub\u003eFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3 \u003c/sub\u003erequires: C, 69.12; H, 5.59; N, 11.52; found C, 69.43; H, 5.87; N, 11.34; LCMS (m/z): 487.4 (M+1); Purity 98.85 %.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.\u003c/strong\u003e\u003cstrong\u003e18\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN-Cyclohexyl-2-(4-fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (88):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing \u003cem\u003eN\u003c/em\u003e-cyclohexyl-2-(4-fluorophenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e60\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.56 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e88\u003c/strong\u003e) was obtained as a yellowish white solid (0.61 g, 82.43 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 195-196 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.46 (80 % Ethyl acetate in hexane); IR: 3322, 2928, 2850, 1649, 1502, 1473, 1270, 1223, 1004, 829, 701 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.71 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 8.85-8,83 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.62-8.59 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.86-7.85 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.57-7.54 (q, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.41-7.38 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.32-7.30 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.15-7.11(d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 6.99-6.97 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 3.77-3.75 (d, 3H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2, \u003c/sub\u003eC\u003cem\u003eH\u003c/em\u003e ), 3.49-3.47 (d, 1H, C\u003cem\u003eH\u003c/em\u003e), 2.41 (bs, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.26 (bs, 3H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 1.69-1.51 (m, 5H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 1.22-1.09 (m, 5H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e28\u003c/sub\u003eH\u003csub\u003e33\u003c/sub\u003eFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e2 \u003c/sub\u003erequires: C, 70.56; H, 6.98; N, 11.76; found C, 70.38; H, 7.17; N, 11.48; Mass (m/z): 477.4 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.19\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)-N-phenyl- acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (89):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing 2-(4-methoxyphenyl)-\u003cem\u003eN\u003c/em\u003e-phenyl-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e61\u003c/strong\u003e) (0.5 g, 1.54 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e89\u003c/strong\u003e) was obtained as a white solid (0.56 g, 75.67 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 96-99 \u0026deg;C; TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.56 (80 % Ethyl acetate in hexane); IR: 3305, 3056, 2931, 2815, 1685, 1507, 1439, 1246, 1176, 1133, 1030 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.97 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.72 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.84-8.83 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.86-8.60 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.59-7.55 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.39-7.37 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.32-7.25 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.04-7.01 (t, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.98-6.96 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.91-6.88 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 3.90 (s, 1H, CH), 3.76 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 3.72 (s, 3H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 2.67 (s, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 2.33 (s, 4H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e30\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3 \u003c/sub\u003erequires: C, 72.18; H, 6.27; N, 11.61; found C, 72.06; H, 6.49; N, 11.49; Mass (m/z): 483.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.\u003c/strong\u003e\u003cstrong\u003e20\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)-N-(o-tolyl) acetamide\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (90): \u003c/strong\u003eUsing 2-(4-methoxyphenyl)-2-(piperazin-1-yl)-\u003cem\u003eN\u003c/em\u003e-(\u003cem\u003eo\u003c/em\u003e-tolyl)acetamide (\u003cstrong\u003e62\u003c/strong\u003e) (0.5 g, 1.47 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e90\u003c/strong\u003e) was obtained as a greenish white solid (0.58 g, 79.45 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 86-88 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.62 (80 % Ethyl acetate in hexane); IR: 3332, 2922, 2833, 1689, 1608, 1582, 1505, 1229, 786 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.70 (d, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.54 (d, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.90-8.78 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 8.65-8.33 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.62-7.48 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.37-7.28 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.25-7.04 (m, 2H\u003cem\u003e, \u003c/em\u003eAr\u003cem\u003eH\u003c/em\u003e), 6.97 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 6.87 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 4.80-4.27 (m, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 3.97 (d, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.81-3.69 (m, 3H, OC\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e), 2.37 (bs, 4H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 2.18 (bs, 3H, C\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e); \u003csup\u003e13\u003c/sup\u003eC NMR \u0026delta;: 169.21, 158.81, 152.79, 151.90, 147.72, 138.83, 135.96, 133.70, 132.86, 130.23, 128.77, 127.77, 126.67, 126.08, 124.76, 123.28, 121.41, 113.59, 110.58, 109.88, 73.99, 59.53, 54.98, 52.67, 17.60. C\u003csub\u003e30\u003c/sub\u003eH\u003csub\u003e32\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3 \u003c/sub\u003erequires: C, 72.56; H, 6.50; N, 11.28; found C, 72.75; H, 6.82; N, 11.06; Mass (m/z): 497.4 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.21\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)-N-(p-tolyl) acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (91):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing 2-(4-methoxyphenyl)-2-(piperazin-1-yl)-\u003cem\u003eN\u003c/em\u003e-(\u003cem\u003ep\u003c/em\u003e-tolyl)acetamide (\u003cstrong\u003e63\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.47 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e91\u003c/strong\u003e) was obtained as a white solid (0.51 g, 69.86 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 103-105 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.48 (80 % Ethyl acetate in hexane); IR: 3327, 3037, 2921, 1686, 1580, 1506, 1473, 1418, 1370, 1274, 1224, 1192, 1251, 781 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.69 (s, 2H, N\u003cem\u003eH, \u003c/em\u003eO\u003cem\u003eH\u003c/em\u003e), 8.87-8.88 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 8.47-8.45 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.66-7.37 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.07-6.90 (m, 5H, Ar\u003cem\u003eH\u003c/em\u003e), 4.68 (s, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 3.88-3.72 (m, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.36 (s, 3H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 2.57 (dd, 3H, C\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e), 2.34-2.14 (m, 4H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e); C\u003csub\u003e30\u003c/sub\u003eH\u003csub\u003e32\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3 \u003c/sub\u003erequires: C, 72.56; H, 6.50; N, 11.28; found C, 72.74; H, 6.73; N, 11.06; Mass (m/z): 497.4 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.22\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003e2-(4-((8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N-(2-methoxyphenyl)-2-(4-methoxyphenyl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (92):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-(2-methoxyphenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e64\u003c/strong\u003e) \u003cem\u003e(\u003c/em\u003e0.5 g, 1.40 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e92\u003c/strong\u003e) was obtained as a yellowish white solid (0.58 g, 80.55 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 153-155 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.46 (80 % Ethyl acetate in hexane); IR: 3314, 2927, 2832, 1689, 1599, 1460, 1371, 1248, 1115, 1028 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e 1\u003c/sup\u003eH NMR: \u0026delta; 9.95 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.71 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.85-8.83 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.61-8.60 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e ), 8.11-8.09 (s, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.58-7.54 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.36-7.34 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.22-7.20 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.11-7.07 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.01-6.99 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.94-6.90 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 4.13 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.95 (s, 3H, OC\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e), 3.84-3.79 (d, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 3.76 (s, 3H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 2.35 (s, 9H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e); C\u003csub\u003e30\u003c/sub\u003eH\u003csub\u003e32\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e requires: C, 70.29; H, 6.29; N, 10.93; found C, 70.08; H, 6.47; N, 10.76; Mass (m/z): 513.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.23\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003e2-(4-((\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e\u003cem\u003e8-Hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-N,2-bis(4-methoxyphenyl)- acetamide \u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e(93)\u003c/strong\u003e: Using \u003cem\u003eN\u003c/em\u003e,2-bis(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e65\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.40 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e93\u003c/strong\u003e) was obtained as a yellowish white solid (0.60 g, 83.33 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 145-147\u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.49 (80 % Ethyl acetate in hexane); IR: 3307, 2822, 1664, 1508, 1468, 1232, 1175, 1133, 1029 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e 1\u003c/sup\u003eH NMR: \u0026delta; 9.84 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.69 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.85-8.83 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e ), 8.63-8.60 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.58-7.55 (m, \u003cem\u003eJ\u003c/em\u003e = 4.5 Hz, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.50-7.47 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.38-7.36 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.33-7.31 (d,1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.99-6.97 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.90-6.83 (m, 4H, Ar\u003cem\u003eH\u003c/em\u003e), 3.86 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.77 (s, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 3.72 (s, 3H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 3.70 (s, 3H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 2.51-2.38 (s, 8H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e); C\u003csub\u003e30\u003c/sub\u003eH\u003csub\u003e32\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e4 \u003c/sub\u003erequires: C, 70.29; H, 6.29; N, 10.93; found C, 69.95; H, 6.61; N, 10.76; Mass (m/z): 513.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.24\u003c/strong\u003e\u003cem\u003e \u003cstrong\u003eN\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e\u003cem\u003e-(4-Fluorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetamide \u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e(94)\u003c/strong\u003e\u003cem\u003e: \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-(4-fluorophenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e66\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.45 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e94\u003c/strong\u003e) was obtained as a yellowish white solid (0.57 g, 78 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 160-163\u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.51 (80 % Ethyl acetate in hexane); IR:3294, 3002, 2937, 2817, 1689, 1610, 1508, 1371, 1301, 1247, 1135, 1007, 832 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 10.04 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.71 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.84-8.83 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.62-8.60 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.62-7.55 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.42-7.30 (dd, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.13-7.09 (t, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 6.99-6.88 (dd, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 3.87 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.76 (s, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 3.72 (s, 3H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 2.45-2.33 (bs, 7H); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e29\u003c/sub\u003eFN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3 \u003c/sub\u003erequires: C, 69.58; H, 5.84; N, 11.19; found C, 69.34; H, 5.95; N, 11.06; Mass (m/z): 501.3 (M\u003csup\u003e+\u003c/sup\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.25\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003eN-(4-Chlorophenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (95):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing of\u003cem\u003e N\u003c/em\u003e-(4-chlorophenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e67\u003c/strong\u003e) \u003cem\u003e \u003c/em\u003e(0.5 g, 1.38 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e95\u003c/strong\u003e) was obtained as a green solid (0.56 g, 77.77 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 135-138 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.52 (80 % Ethyl acetate in hexane); IR: 3316, 2817, 1692, 1583, 1504, 1473, 1372, 1232, 1177, 1005, 787 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 10.12 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.71 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.88-8.84 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.63-8.61 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.65-7.63 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.59-7.56 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.40-7.32 (m, 5H, Ar\u003cem\u003eH\u003c/em\u003e), 6.99-6.98 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.92-6.90 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 3.91 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 3.73 (s, 3H, OC\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e), 2.46-2.35 (d, 8H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e29\u003c/sub\u003eClN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e requires: C, 67.37; H, 5.65; N, 10.84; found C, 67.61; H, 5.98; N, 10.62; Mass (m/z): 517.3 (M\u003csup\u003e+\u003c/sup\u003e), 519.1 (M+2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.26\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003eN-(4-Hydroxyphenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (96):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-(4-hydroxyphenyl)-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (\u003cstrong\u003e68\u003c/strong\u003e)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.46 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e96\u003c/strong\u003e) was obtained as an orange solid (0.54 g, 73.97 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate: Hexane as mobile phase, m.p. 170-172 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.38 (80 % Ethyl acetate in hexane); IR: 3317, 2948, 2820, 1659, 1607, 1510, 1476, 1371, 1233, 1180, 1032 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 10.06 (bs, 1H, O\u003cem\u003eH\u003c/em\u003e), 9.73 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 9.20 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.90-8.84 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.65-8.61 (t, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 8.01-7.85 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.71-7.66 (m, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 7.58-7.55 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.45-7.41 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.38-7.31 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 7.10-6.97 (dd, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.90-6.88 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.67-6.65 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 3.85 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.78 (s, 2H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e,\u003c/em\u003e), 3.73 (s, 3H, OC\u003cem\u003eH\u003csub\u003e3\u003c/sub\u003e\u003c/em\u003e), 2.34 (bs, 8H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e30\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e4 \u003c/sub\u003erequires: C, 69.86; H, 6.07; N, 11.24; found C, 69.69; H, 6.25; N, 11.15; Mass (m/z): 499.3 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.6.1.27\u003c/strong\u003e\u003cem\u003e \u003c/em\u003e\u003cstrong\u003e\u003cem\u003eN-(4-Hydroxyphenyl)-2-(4-((8-hydroxyquinolin-5-yl)methyl)piperazin-1-yl)-2-(4-methoxyphenyl)acetamide\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e (97):\u003c/strong\u003e\u003cem\u003e \u003c/em\u003eUsing\u003cem\u003e N\u003c/em\u003e-cyclohexyl-2-(4-methoxyphenyl)-2-(piperazin-1-yl)acetamide (69)\u003cem\u003e \u003c/em\u003e(0.5 g, 1.50 mM) and \u003cstrong\u003eMethod D\u003c/strong\u003e the desired compound (\u003cstrong\u003e97\u003c/strong\u003e) was obtained as a white solid (0.63 g, 85.13 %), which was further purified by column chromatography using 100-200 silica gel as stationary phase and Ethyl acetate:Hexane as mobile phase, m.p. 197-199 \u0026deg;C. TLC (R\u003csub\u003ef\u003c/sub\u003e): 0.52 (80 % Ethyl acetate in hexane); IR: 3325, 2934, 2852, 2817, 1644, 1509, 1475, 1376, 1246, 1180, 1135, 1006 \u003cem\u003ecm\u003csup\u003e-1\u003c/sup\u003e\u003c/em\u003e; \u003csup\u003e1\u003c/sup\u003eH NMR: \u0026delta; 9.91 (s, 1H, N\u003cem\u003eH\u003c/em\u003e), 8.84 (s, 1H, O\u003cem\u003eH\u003c/em\u003e), 8.61-8.58 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.78-7.76 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.57-7.54 (m, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 7.31-7.25 (m, 3H, Ar\u003cem\u003eH\u003c/em\u003e), 6.98-6.96 (d, 1H, Ar\u003cem\u003eH\u003c/em\u003e), 6.86-6.84 (d, 2H, Ar\u003cem\u003eH\u003c/em\u003e), 3.75 (s, 2H, C\u003cem\u003eH\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), 3.72 (s, 3H, OC\u003cem\u003eH\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e), 3.66 (s, 1H, C\u003cem\u003eH\u003c/em\u003e), 3.47 (bs, 1H, C\u003cem\u003eH\u003c/em\u003e), 2.44-2.40 (m, 8H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 1.64-1.51 (m, 5H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e), 1.23-1.09 (m, 5H, C\u003cem\u003eH\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e); C\u003csub\u003e29\u003c/sub\u003eH\u003csub\u003e36\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e3 \u003c/sub\u003erequires: C, 71.28; H, 7.43; N, 11.47; found C, 71.40; H, 7.75; N, 11.13; Mass (m/z): 489.4 (M+1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.7 Biological Activity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.7.1 \u003cem\u003eInhibition studies on AChE and BuChE\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe potential of the test compounds for cholinesterase inhibition was assessed using Ellman\u0026apos;s essay.[39\u0026ndash;41] The products that were purchased from Sigma-Aldrich included human AChE (product number C1682), equine serum BuChE (CAS 9001-08-5), 5,5\u0026rsquo;-dithiobis (2-nitrobenzoic acid) (DTNB, product number T-D0944), acetylthiocholine iodide (ATCI, product number T-A0116), and butyrylthiocholine iodide (BTCI, product number T-B0775). Standard drugs were donepezil hydrochloride and tacrine hydrochloride hydrate. Every experiment was conducted at pH 8 in a 50 mM Tris-Hydrochloride buffer (Tris HCl, product number MB030). To ascertain the enzyme inhibitory activity, five distinct doses (0.001\u0026minus;100 \u0026mu;M) of every test chemical were employed. To summarize, 10 \u0026mu;L of the test or reference compounds were incubated in 50 \u0026mu;L of AChE (0.22 U/mL) or 50 \u0026mu;L of BuChE (0.06 U/mL)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.7.2 \u003cem\u003eAntioxidant activity [1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity]\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003ch4\u003ea) Preparation of DPPH reagent: A solution of 2,2-diphenyl-1-picrylhydrazyl (DPPH) (0.1mM) was prepared in methanol. \u003c/h4\u003e\n\u003ch4\u003eb) Preparation of Sample/Standard\u003c/h4\u003e\n\u003cp\u003eBased on the scavenging activity of the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH), free radical scavenging activity of the synthesized compounds was determined by the method of Ali \u003cem\u003eet al\u003c/em\u003e [43]\u003cstrong\u003e.\u003c/strong\u003e Different volumes (20 \u0026ndash; 100\u0026mu;g/ml) of standard compound ascorbic acid and the synthesized compounds were taken from a stock solution in a set of test tubes, and methanol was added to make the volume to 1 ml. To this, 2 ml of 0.1mM DPPH reagent was added and mixed thoroughly. Absorbance at 517 nm was determined after 30 min. \u003c/p\u003e\n\u003ch4\u003eC) Preparation of control\u003c/h4\u003e\n\u003cp\u003eFor control, DPPH (3 ml of 0.1mM solution) was taken and incubated for 30 min at room temperature in dark conditions. The absorbance of the control was taken against methanol (as blank) at 517 nm [44]\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe percentage antioxidant activity of the sample/standard was calculated by using the formula:\u003c/p\u003e\n\u003cp\u003e% Inhibition = [(Ab of control- Ab of sample/Ab of control] x 100\u003c/p\u003e\n\u003cp\u003eThe lower the absorbance, the higher the free radical scavenging activity. The curves were prepared and the IC\u003csub\u003e50\u003c/sub\u003e values were calculated using linear regression analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.7.3 \u003cem\u003eMetal-chelating study\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe metal chelating ability of all the compounds was assessed using UV spectrophotometry [45]. The absorption spectra of the test compounds (25 \u0026mu;M) alone and in the presence of CuSO\u003csub\u003e4\u003c/sub\u003e, ZnCl\u003csub\u003e2\u003c/sub\u003e, FeSO\u003csub\u003e4\u003c/sub\u003e, FeCl\u003csub\u003e3 \u003c/sub\u003eand AlCl\u003csub\u003e3\u003c/sub\u003e (25 \u0026mu;M) in methanol for 30 min were recorded at room temperature in the UV-visible range.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.7.4 \u003cem\u003eADME Prediction\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBefore a molecule is introduced into the market, its efficacy and safety are vital considerations. An examination of its ADMET (absorption, distribution, metabolism, excretion, and toxicity) profile can be one way to look at these features [46]. Using the online SwissADME server [47], the ADMET properties of the synthesized compounds were evaluated.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eWorld\u0026rsquo;s population is slowly inching towards a continuously growing pool of old-age people every year. Apart from other age-related ailments, Alzheimer\u0026rsquo;s disease is posing a serious problem in the society. A worrying fact is poor understanding of the disease despite so much of advancements in the medical field, and absence of curative therapeutics. In our quest to develop some acceptable anti-Alzheimer\u0026rsquo;s agents we used molecular hybridization approach to combine some anti-Alzheimer\u0026rsquo;s savvy molecular fragments, like piperazine, 8-hydroxyquinoline and acetamido groups into a singular molecular entity to design some potential anti-Alzheimer\u0026rsquo;s agents. Modifications were made by attaching aromatic/alicyclic amines through acetamide linkers to the 5-(piperazin-1-ylmethyl)quinolin-8-ol scaffold, resulting in a novel series of anti-AD agents. The designed compounds displayed excellent affinity towards both the enzymes with docking scores in the range of -12.8 to -10.6 kcal/mol for AChE, and \u0026minus;\u0026thinsp;12.4 to -10.3 kcal/mol for BuChE which were higher than the scores obtained for the standard compound\u0026rsquo;s donepezil (-10.8 kcal/mol) and Tacrine (-8.4 kcal/mol). Among them, compounds having a 4-chloroanilino moiety and a 4-methoxyphenyl group, exhibited the most promising inhibitory activities against AChE (with an IC\u003csub\u003e50\u003c/sub\u003e value of 3.013 \u0026micro;M) and BuChE (with an IC\u003csub\u003e50\u003c/sub\u003e value of 3.144 \u0026micro;M). Compound (\u003cb\u003e83\u003c/b\u003e), with 2-methoxyaniline and 4-fluorobenzene substituents, offered the highest BuChE inhibition with an IC\u003csub\u003e50\u003c/sub\u003e value of 1.888 \u0026micro;M. Additionally, compound \u003cb\u003e(79)\u003c/b\u003e offered 93 times higher selectivity for BuChE over AChE. All the compounds displayed metal chelating ability with (Fe\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e, Fe\u003csup\u003e+\u0026thinsp;3\u003c/sup\u003e, Zn\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e, Cu\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e, and Al\u003csup\u003e+\u0026thinsp;3\u003c/sup\u003e), as well as moderate antioxidant activity. Molecular modelling studies indicated significant interactions between the most potent compounds (\u003cb\u003e83\u003c/b\u003e, \u003cb\u003e95\u003c/b\u003e) and the PAS and CAS sites of the enzymes. Furthermore, all the compounds offered acceptable \u003cem\u003ein silico\u003c/em\u003e pharmacokinetic properties including twenty compounds showing BBB permeability. These results collectively suggested that compound (\u003cb\u003e95\u003c/b\u003e) could be a leading candidate with high potential for further development as a novel anti-AD drug by inhibiting both AChE and BuChE. At the same time, compound \u003cb\u003e(79)\u003c/b\u003e can be a potent and selective BuChE Inhibitor.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe acknowledge Research and development cell, Parul University, Vadodara, Gujarat, India for providing funding as part of intramural research grant for the successful completion of the project.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eM.R. Yadav conceptualized the whole study. A. A. Nagani, M. N. Shah and S. I. Patel carried out the synthesis and data collection, and H. A. Patel and M. N. Shah planned and executed computational studies. V. K. Parikh, A. D. Patel, and B. C. Bhimani assisted in data collection and data interpretation. K. V. Patel designed the biological studies and H. R. Parmar and S. P. Patel performed biological studies and data collection. A. A. Nagani, S. I. Patel, and M. N. Shah drafted the manuscript. All authors reviewed and approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this manuscript. The authors declare that they do not have any conflict of interest. The authors declare that this manuscript is original, has not been published before, and is not currently being considered for publication elsewhere. We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ehttps://\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ealzheimersnewstoday.com/what-is-alzheimers-disease/\u003c/span\u003e\u003cspan address=\"http://alzheimersnewstoday.com/what-is-alzheimers-disease/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://alzheimersnewstoday.com/alzheimers-disease-statistics/\u003c/span\u003e\u003cspan address=\"https://alzheimersnewstoday.com/alzheimers-disease-statistics/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShah H, Patel A, Parikh V, Nagani A, Bhimani B, Shah U, Bambharoliya T (2020) The β-Secretase Enzyme BACE1: A Biochemical Enigma for Alzheimer\u0026rsquo;s disease. CNS \u0026amp; Neurological Disorders-Drug Targets (Formerly Current Drug Targets-CNS \u0026amp; Neurological Disorders). 19(3):184\u0026ndash;194\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePatel DV, Patel NR, Kanhed AM, Teli DM, Patel KB, Gandhi PM, Patel SP, Chaudhary BN, Shah DB, Prajapati NK, Patel KV (2020) Further studies on triazinoindoles as potential novel multitarget-directed anti-alzheimer\u0026rsquo;s agents. ACS Chem Neurosci 11(21):3557\u0026ndash;3574\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePatel KB, Patel DV, Patel NR, Kanhed AM, Teli DM, Gandhi B, Shah BS, Chaudhary BN, Prajapati NK, Patel KV, Yadav MR (2022) Carbazole-based semicarbazones and hydrazones as multifunctional anti-Alzheimer agents. 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Asian Pac J Trop Biomed 3(6):464\u0026ndash;469\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAl-Rimawi F, Rishmawi S, Ariqat SH, Khalid MF, Warad I, Salah Z (2016) Anticancer activity, antioxidant activity, and phenolic and flavonoids content of wild Tragopogon porrifolius plant extracts. Evidence-Based Complementary and Alternative Medicine. ; 2016\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSavelieff MG, Lee S, Liu Y, Lim MH (2013) Untangling amyloid-β, tau, and metals in Alzheimer\u0026rsquo;s disease. ACS Chem Biol 8(5):856\u0026ndash;865\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKumar N, Goel N, Chand Yadav T, Pruthi V (2017) Quantum chemical, ADMET and molecular docking studies of ferulic acid amide derivatives with a novel anticancer drug target. Med Chem Res 26(8):1822\u0026ndash;1834\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.swissadme.ch\u003c/span\u003e\u003cspan address=\"http://www.swissadme.ch\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003eTable 4 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"molecular-diversity","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"modi","sideBox":"Learn more about [Molecular Diversity](http://link.springer.com/journal/11030)","snPcode":"11030","submissionUrl":"https://submission.nature.com/new-submission/11030/3","title":"Molecular Diversity","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Piperazine, Quinoline, Acetylcholinesterase, Butyrylcholinesterase, Metal chelation, Antioxidant","lastPublishedDoi":"10.21203/rs.3.rs-4098574/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4098574/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMulti-target directed ligands (MTDLs) have recently been popularized due to their outstanding efficacy in combating the complicated features of Alzheimer's disease. This study details the synthesis of piperazine-quinoline-based MTDLs through a multicomponent Petasis reaction, targeting multiple factors such as AChE, BuChE, metal chelation to restore metal dyshomeostasis, and antioxidant activity. Some of the synthesized compounds exhibited notable inhibitory activity against AChE and BuChE enzymes at specific concentrations. Among the synthesized compounds compound (\u003cstrong\u003e95\u003c/strong\u003e) containing a 4-chloroaniline moiety and a 4-methoxybenzyl group displayed the most promising inhibitory activities against AChE (IC\u003csub\u003e50\u003c/sub\u003e 3.013 µM) and BuChE (IC\u003csub\u003e50\u003c/sub\u003e = 3.144 µM). Compound (\u003cstrong\u003e83\u003c/strong\u003e) featuring 2-methoxyaniline and 4-fluorobenzyl substituents, exhibited the highest BuChE inhibition (IC\u003csub\u003e50\u003c/sub\u003e 1.888 µM). Notably, compound (\u003cstrong\u003e79\u003c/strong\u003e) demonstrated 93-times higher selectivity for BuChE over AChE. Out of these compounds nine compounds were assessed for antioxidant activity, displaying significant potential at a concentration of 100 μM. Moreover, all the compounds demonstrated metal chelating activity with Cu\u003csup\u003e+2\u003c/sup\u003e, Zn\u003csup\u003e+2\u003c/sup\u003e, Fe\u003csup\u003e+2\u003c/sup\u003e, Fe\u003csup\u003e+3\u003c/sup\u003e and Al\u003csup\u003e+3\u003c/sup\u003e. This study provides insights into the design of novel MTDLs, highlighting compound (\u003cstrong\u003e95\u003c/strong\u003e) as a potential candidate for Inhibiting Alzheimer's disease and emphasizing its role in the development of anti-AD medication.\u003c/p\u003e","manuscriptTitle":"Unveiling Piperazine-Quinoline Hybrids as Potential Multi-Target Directed Anti- Alzheimer’s Agents: Design, Synthesis and Biological Evaluation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-03-20 10:22:38","doi":"10.21203/rs.3.rs-4098574/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-04-11T04:28:18+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-03-21T15:54:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"3a2bb70f-058d-4d19-8a64-efcf8aeda6cf","date":"2024-03-21T08:19:43+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-03-21T03:38:36+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-03-18T14:47:16+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-03-14T14:36:49+00:00","index":"","fulltext":""},{"type":"submitted","content":"Molecular Diversity","date":"2024-03-14T08:09:33+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"molecular-diversity","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"modi","sideBox":"Learn more about [Molecular Diversity](http://link.springer.com/journal/11030)","snPcode":"11030","submissionUrl":"https://submission.nature.com/new-submission/11030/3","title":"Molecular Diversity","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"d7c98094-a030-48d7-893d-f851423bfdf4","owner":[],"postedDate":"March 20th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2024-07-02T18:38:29+00:00","versionOfRecord":[],"versionCreatedAt":"2024-03-20 10:22:38","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4098574","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4098574","identity":"rs-4098574","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}