A Mild, One-Pot Preparation of 2-Substituted Benzimidazoles From Organic Halides

Alkyl halides are feasibly transformed into benzimidazoles by an domino reaction under solvent-free conditions. The organic halides react with orthophenylenediamines in stoichiometric amounts in the presence of pyridine-N-oxide to produce the desired substituted benzimidazoles. This domino synthesis does not requires catalysts. The synthesis occurs in dry medium and the environmental impact is minimal. The method provides products without intermediate separation. A mechanism of benzimidazole synthesis is also proposed.