Microwave-Enhanced, Additive-Free C-H Amination of Benzoxazoles Catalysed by supported Copper

chemistry Medicinal and pharmaceutical chemistry Nano- and molecular-scale electronics Nano-biomaterials and bioscience Nanomagnetics Nanomaterials, thin films and nanointerfaces Nanomedicine Nanometrology and nanomechanics Nano-optics Nanopatterning, self-assembly and nanofabrication Nanostructures for energy and sensing applications Natural products chemistry Organo main group chemistry Other nanotechnology (unclassified) Other organic chemistry (unclassified) Photochemistry and photovoltaics Physical organic chemistry Supramolecular chemistry The C2 amination of benzoxazole offers wide-ranging potential for substrate expansion and the functionalisation of bioactive compounds. This study presents a green and efficient C-H amination, catalysed by CuCl and CuCl₂, in acetonitrile without acidic, basic or oxidant additives that is accelerated by Microwave (MW) irradiation and is completed in 1.5–2 h. A solid Cu(I) catalyst supported on aminated silica made the process cost-effective and heterogeneous, thus simplifying work-up and minimising free copper in solution. The catalyst was found to be regenerable and reusable for up to eight cycles. The optimised method facilitated the synthesis of various benzoxazole derivatives, demonstrating its versatility and practical applicability.

Heterogeneous catalysis; Microwave; Aerobic oxidation; Grafted silica; Copper | Format: PDF | Size: 2.9 MB | Download | When a peer-reviewed version of this preprint is available, this information will be updated in the information box above. If no peer-reviewed version is available, please cite this preprint using the following information: Paraschiv, A.; Maruzzo, V.; Pettazzi, F.; Magliocco, S.; Inaudi, P.; Brambilla, D.; Berlier, G.; Cravotto, G.; Martina, K. Beilstein Arch. 2025, 202514. doi:10.3762/bxiv.2025.14.v1 Citation data can be downloaded as file using the "Download" button or used for copy/paste from the text window below. Citation data in RIS format can be imported by all major citation management software, including EndNote, ProCite, RefWorks, and Zotero. © 2025 Paraschiv et al.; licensee Beilstein-Institut. This is an open access work licensed under the terms of the Beilstein-Institut Open Access License Agreement (https://www.beilstein-archives.org/xiv/terms), which is identical to the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0). The reuse of material under this license requires that the author(s), source and license are credited. Third-party material in this work could be subject to other licenses (typically indicated in the credit line), and in this case, users are required to obtain permission from the license holder to reuse the material.