Zeolite hy catalyst for the synthesis of benzimidazole and its 2-alkyl, aryl and heteroaryl derivatives under microwave irradiation and solvent-free condition

A simple, fast, efficient and environmentally friendly 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 leads to 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