Copper-Promoted One-Pot Approach: Synthesis of Benzimidazoles.

A facile, one-pot, and proficient method was developed for the production of various 2-arylaminobenzimidazoles. This methodology is based for the first time on a copper catalyst promoted domino C-N cross-coupling reaction for the generation of 2-arylaminobenzimidazoles. Mechanistic investigations revealed that the synthetic pathway involves a copper-based desulphurization/nucleophilic substitution and a subsequent domino intra and intermolecular C-N cross-coupling reactions. Some of the issues typically encountered during the synthesis of 2-arylaminobezimidazoles, including the use of expensive catalytic systems and the low reactivity of bromo precursors, were addressed using this newly developed copper-catalyzed method. The reaction procedure is simple, generally with excellent substrate tolerance, and provides good to high yields of the desired products.

Copper-catalyzed synthesis of 2-aminophenyl benzothiazoles: a novel approach.

A novel, convenient and efficient protocol for the construction of various 2-aminophenyl benzothiazoles by domino intra- and intermolecular C-N cross-coupling reactions of arylisothioureas with aryl iodides using an inexpensive, air stable and readily available copper catalyst is described. The arylisothioureas were obtained from thiourea via copper promoted desulfurization followed by nucleophilic substitution. In addition, the reactivity of arylhalides and the reaction mechanism have also been studied. The protocol features operational simplicity and a broad substrate scope.