The synthesis of substituted benzimidazoles, 2-aminobenzimidazoles, 2-aminobenzothiazoles, and benzoxazoles is described via intramolecularcyclization of o-bromoaryl derivatives using copper(II) oxide nanoparticles in DMSO under air. The procedure is experimentally simple, general, efficient, and free from addition of external chelating ligands. It is a heterogeneous process and the copper(II) oxide
Metal-Free Synthesis of 2-Substituted (N, O, C) Benzothiazoles via an Intramolecular C−S Bond Formation
作者:Enguang Feng、He Huang、Yu Zhou、Deju Ye、Hualiang Jiang、Hong Liu
DOI:10.1021/cc9001839
日期:2010.7.12
convenient method was developed for the preparation of 2-substituted (N, O, C) benzothiazoles from N'-substituted-N-(2-halophenyl)thioureas, O'-substituted-N-(2-halophenyl) carbamothioates, or N-(2-halophenyl) thioamides via a base-promoted cyclization in dioxane without any transition metal. A one-pot variant combining the synthesis of the thiourea and the cyclization was also demonstrated. High yields
Copper- and Palladium-Catalyzed Intramolecular Aryl Guanidinylation: An Efficient Method for the Synthesis of 2-Aminobenzimidazoles
作者:Ghotas Evindar、Robert A. Batey
DOI:10.1021/ol027061h
日期:2003.1.1
The formation of 2-aminobenzimidazoles via intramolecular C-N bond formation between an aryl halide and a guanidine moiety can be achieved using either copper or palladium catalysis. Inexpensive copper salts such as Cul are generally superior to the use of palladium catalysts. Regioselective cyclizations, where R-3 = H, can be achieved in high yield under Cul/1,10-phenanthroline-catalyzed conditions, whereas palladium catalysis results in the formation of regioisomeric products.
Copper(I)-Catalyzed Synthesis of Substituted 2-Mercapto Benzimidazoles
作者:Siva Murru、Bhisma K. Patel、Jean Le Bras、Jacques Muzart
DOI:10.1021/jo802589d
日期:2009.3.6
An efficient method for the preparation of various substituted 2-mercapto benzimidazoles from their corresponding thioureas has been developed. S-Alkylation of thioureas followed by Cu-catalyzed intramolecular N-arylation furnished substituted 2-mercapto benzimidazoles in high yields and short reaction times. Furthermore, 2-mercapto benzimidazoles substituted with a p-methoxybenzyl group allowed access to benzimidazole thiones.
REMBARZ, G.;FISCHER, E.;KOSITZKI, D.;MICHALIK, M., WISS. Z. WILHELM-PIECK-UNIV. ROSTOCK. NATURWISS. R., 1984, 33, N 8, 49-52
作者:REMBARZ, G.、FISCHER, E.、KOSITZKI, D.、MICHALIK, M.