Oxidative Coupling of o-Phenylenediamine with Arylmethylamines to Synthesize Aryl-Substituted Benzimidazoles Under Catalyst-Free and Solvent-Free Conditions

Solvent-free oxidative synthesis of benzimidazoles from arylmethylamines and o-phenylenediamine has been achieved under catalyst-free conditions. This reaction can use tert-butyl hydroperoxide (TBHP) as the oxidant, and a wide variety of derivatives were obtained in good yields. The reaction mechanism was proposed and this method provides a direct and practical approach for the preparation of substituted benzimidazoles.