Glyoxylic acid as catalyst: A simple selective synthesis of 1,2-disubstituted benzimidazoles in aqueous media

Glyoxylic acid (5 mol%) performs as a novel highly water-soluble catalyst for the synthesis of 2-aryl-1-arylmethyl-1 H-benzimidazoles from a wide range of substituted o-phenylenediamines and various substituted aldehydes in good to excellent isolated yields (85–95%) using water as solvent at ambient temperature. The remarkable advantages offered by this method are easily and inexpensive available catalyst, simple procedure, mild conditions, much faster (20–40 min) reactions and excellent yields of products.