The benzimidazole nucleus is of significant importance to medicinal chemistry and many benzimidazole-containing compounds exhibit important biological activities such as selective neuropeptide YY1 receptor antagonism, and as 5-lipoxygenase inhibitors for use as novel antiallergic agents, factor Xa (FXa) inhibitors, poly (ADP-ribose) polymeras (PARP) inhibitors, and as human cytomegalovirus (HCMV) inhibitors. The synthesis of benzimidazoles traditionally involves the condensation of o- phenylendiamine with aldehydes, and carboxylic acids or their derivatives (nitriles, amidates, orthoesters) under harsh dehydrating conditions. Benzimidazoles have also been prepared on solid-phase to provide a combinatorial approach. Another approach reported to these compounds is the reaction of o- phenylendiamine with aldehydes in the presence of catalysts under various reaction conditions. Recently, a one-pot solvent-free synthesis of biologically active benzimidazole derivatives using a simple grinding method, and also under the heterogeneous catalysis of Amberlite IR-120 has been reported. We report here a series of 2-aryl-1-arylmethyi-1H-1, 3-benzimidazoles were prepared in high to excellent yields by three methods .
