An elegant approach for selective synthesis of 2-substituted benzimidazoles at room temperature using Ag nanoparticles as an activator: effect of solvent on the selectivity

Abstract

An expedient, competent, and green protocol was developed for the selective synthesis of 2-substituted benzimidazole by the condensation of 1,2-diaminobenzene and various aldehydes, including aromatic, heteroaromatic, and aliphatic aldehydes, in methanol and water (1:1) as reaction media in the presence of Ag nanoparticles in a one pot operation at room temperature. The selectivity of the protocol for obtaining 2-substituted benzimidazole is highly dependent on the ratios of methanol and water used, as well as the reaction temperature. The present protocol exhibits several advantages, such as high yield, short reaction time, high selectivity, and no side reaction, and it works at room temperature, which makes this methodology green, providing a practical input to the existing procedures available for the synthesis of 2-substituted benzimidazole derivatives.