Water-Accelerated Selective Synthesis of 1,2-Disubstituted Benzimidazoles at Room Temperature Catalyzed by Brnsted Acidic Ionic Liquid

An environmentally benign method for the rapid and selective synthesis of 2-aryl-1-arylmethyl-1H-1,3-benzimidazoles by the reaction of o-phenylenediamines and aromatic aldehydes in the presence of 1-methylimidazolium triflouroacetate ([Hmim]TFA) at room temperature under aqueous conditions is described. The ionic liquid is reusable and could be recycled for several runs without any decrease in its efficiency.