One-pot synthesis of Benzimidazole derivatives under microwave Irradiation and solvent-free condition

A simple, fast, efficient and environmentally friendly method for synthesis of benzimidazole and its 2-alkyl, aryl and heteroaryl substituted derivatives was developed using zeolite HY. Two component cyclolcondensation of 1,2-phenylenediamine (o-phenylenediamine) and commercially available carboxylic acids catalyzed by zeolite HY without any solvent, under microwave irradiation led to formation of 1H-benzimidazole and 2-substituted derivatives in high yields and purity. The similar reaction was not applicable to the preparation of benzimidazole and its 2-alkyl, aryl and heteroaryl substituted derivatives. All the synthesized compounds were characterized by 1H-NMR, IR, Mass and CHNS analysis.