Zeolite HY Catalyst for the Synthesis of Benzimidazole and its 2-alkyl, aryl and Heteroaryl Derivatives Under Microwave Irradiation and Solvent-Free Condition

Abstract

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.

Keywords:

• benzimidazole
• microwave irradiation
• solvent-free
• zeolite HY

The authors are grateful to the department of Science and Technology (DST), New Delhi, for financial support under the project SR/SD/HS-58/2003. The CHNS, IR and other data obtains from the instruments granted under DST-FIST, UGC-SAP (phase-I) and UGC/ F.31/143/2005 (SR) programs are greatly acknowledged.

Notes

^a In all experiments, the reaction time was 5 min.

^b All reported yields refer to isolated products.