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

Abstract

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.

Keywords:

• Aldehyde
• benzimidazole
• heterocycle
• ionic liquid
• water

ACKNOWLEDGMENTS

We gratefully acknowledge financial support from the Research Council of Shahid Beheshti University.

Notes

^a The 1a/2a ratio was determined by ¹H NMR analysis.

^a Isolated yield.

^b The products were characterized by comparison of their spectroscopic and physical data with authentic samples synthesized by reported procedures.

^c IL was recycled for four runs.