Ag2O/GO/TiO2 Composite Nanostructure: an efficient heterogeneous catalyst for one pot synthesis of Bis (dihydropyrimidinone) and tetrahydro-4H-chromenes derivatives

The simple and efficient synthesis reaction was used for preparing Bis (dihydropyrimidinone) derivatives through Biginelli condensation reaction of terephthalic aldehyde, 1, 3-dicarbonyl compounds and (thio) urea or guanidine and tetrahydro-4H-chromenes via one pot condensation of aromatic aldehydes, malononitrile and dimedone with Ag 2 O/GO/TiO 2 composite nanostructures as a catalyst. The structural functionalities and morphological observations of catalyst were obtained using characterization techniques of field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transfer infrared (FT-IR) spectroscopy and transmission electron microscope (TEM). The structures of Bis (dihydropyrimidinone) and tetrahydro-4H-chromenes confirmed by FT- IR, NMR and mass spectroscopy. Excellent yields of the products, simple reaction process and simple work-up are attractive features of these effective synthesis methods.