Cu(ii)-SBA-15 mediated synthesis of 2-aryl benzimidazoles and benzoxazoles: a sustainable approach

Benzimidazole and benzoxazole scaffolds are widely recognized for their presence in molecules with diverse pharmacological activities, including antiviral, antiulcer, antihypertensive, and anticancer effects. Motivated by their structural and synthetic significance, this work presents a green and efficient approach for the synthesis of 2-aryl benzimidazoles and benzoxazoles via the condensation of o-phenylenediamine or o-aminophenol with substituted benzaldehydes. The reaction is catalysed by Cu(II)-SBA-15, a recyclable and eco-friendly heterogeneous catalyst, offering an environmentally benign alternative to conventional methods. The catalytic system demonstrated a pristine reaction profile, with 100% conversion and 74-86% yields in a short timeframe. The heterogeneous mesoporous Cu-SBA-15 catalyst exhibited easy separability through simple centrifugation/filtration, emerging as a promising catalyst for the efficient and facile synthesis of 2-aryl benzimidazoles and 2-aryl benzoxazoles. Significantly, the catalyst demonstrated broad substrate scope and good recyclability with sustained efficiency, with its commercial viability impending.