title: Copper-catalyzed synthesis of benzimidazoles via cascade reactions of o-haloacetanilide derivatives with amidine hydrochlorides.
abstract: We have developed an efficient method for the synthesis of benzimidazoles via cascade reactions of o-haloacetoanilide derivatives with amidine hydrochlorides. The protocol uses 10 mol % CuBr as the catalyst, Cs2CO3 as the base, and DMSO as the solvent, and no ligand is required. The procedure proceeds via the sequential coupling of o-haloacetoanilide derivatives with amidines, hydrolysis of the intermediates (amides), and intramolecular cyclization with the loss of NH3 to give 2-substituted 1H-benzimidazoles.
authors.affiliation: Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: Daoshan
authors.initials: D
authors.lastname: Yang
authors.forename: Hua
authors.initials: H
authors.lastname: Fu
authors.forename: Liming
authors.initials: L
authors.lastname: Hu
authors.forename: Yuyang
authors.initials: Y
authors.lastname: Jiang
authors.forename: Yufen
authors.initials: Y
authors.lastname: Zhao