Activated alumina ball catalyzed expeditious synthesis of 2-alkylbenzimidazoles with special emphasis on susceptible side chains possessing amide functionality

Department of Chemistry, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata-700 009, India E-mail : cmukhop@yahoo.co.in Department of Chemistry, Howard University, 525 College St., N.W. Washington, D.C. 20059, USA Manuscript received 06 June 2013, accepted 10 June 2013 A solvent- and chromatography-free, non-hazardous green protocol for the synthesis of 2-alkylbenzimidazoles has been developed under neutral conditions with water as the only by-product. Activated alumina balls, which have been shown previously to assist in amidation reaction, also catalyze very successfully the condensation of benzene-1,2- diamines with carboxylic acids to produce the corresponding benzimidazoles. This methodology is also applicable to susceptible side chains possessing an amide functionality