Alternative and efficient method for the preparation of 2-acetamidobenzimidazoles

An alternative method for the synthesis of acetamidobenzimidazoles (3-6) has been developed, including the reacylation of methylbenzimidazol-2-ylcarbamate (carbendazim, MBC, 1) under the action of aliphatic and aromatic carboxylic acids. It was shown that with an increase in the size of the alkyl group and the reaction temperature (in the case of butyric acid), due to the decomposition of the resulting product, the yield of the target acyl products sharply decreases. The obtained compounds are homologues of the anthelmintic drug - N-(1H-benzimidazol-2-yl) acetamide (2acetylaminobenzimidazole, 3). A possible mechanism of reacylation is presented.

Automated summary

An alternative method for the synthesis of acetamidobenzimidazoles has been developed by reacylation of methylbenzimidazol-2-ylcarbamate under the action of aliphatic and aromatic carboxylic acids. The yield of the target acyl products sharply decreases with an increase in the size of the alkyl group and the reaction temperature. The obtained compounds are homologues of the anthelmintic drug - N-(1H-benzimidazol-2-yl) acetamide.