Abstract:

Oxfendazole, a benzimidazolecarbamate(BZC) compound, is a broad-spectrum antihelmintic and antimicrobial agent. The insufficient sources of its impurities affected the quality control of the product. Herein, a simple and efficient method for synthesis of four impurities, fenbendazole, methyl (5-(phenylsulfonyl)-1H-benzo[d]imidazol-2-yl)carbamate, 5-(phenylsulfinyl)-1H-benzo[d]imidazol-2-amine and 1,3-bis(5-(phenylsulfinyl)-1H-benzo[d]imidazol-2-yl)urea, is revealed. Especially, the key imidazole ring was constructed efficiently via two different strategies. Furthermore, oxidative products of sulfur ether, sulphone and sulfoxide were obtained by controlling oxidative conditions. This method not only increases the source of the standard substances for quality control of oxfendazole, but also provides an efficient synthetic strategy to prepare the novel antihelmintic, antimicrobial and antitumor agents based on oxfendazol.

Key words: oxfendazole, impurity, standard substances, synthesis