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, Cs 2 CO 3 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 NH 3 to give 2-substituted 1H-benzimidazoles.
This paper reports an efficient method for synthesising benzimidazoles through cascade reactions of o-haloacetoanilide derivatives with amidine hydrochlorides. 10 mol % CuBr was used as the catalyst and Cs2CO3 as the base. The reactions were carried out in DMSO...
Slight adjustments will give more yields
This paper reports an efficient method for synthesising benzimidazoles through cascade reactions of o-haloacetoanilide derivatives with amidine hydrochlorides. 10 mol % CuBr was used as the catalyst and Cs2CO3 as the base. The reactions were carried out in DMSO...