Alternative and efficient method for the preparation of 2-acetamidobenzimidazoles

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