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
Summary:
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...