Abstract:

It was reported the products of α,β-unsaturated carboxylic acid and o-aminothiophenol with acid catalyst were seven-membered ring benzothiazepins containing a carboxyl group. Subsequent literature suggested that the structure of the reaction product was a six-membered ring lactam structure. According to the reported method we carried out the reaction and the products obtained were not the reported seven-membered ring benzothiazepin structure, but the six-membered ring lactam structures 3a—3k, which structures were confirmed by mapping and crystal structure analysis. Under the different experimental conditions, we obtained seven-membered ring benzothiazepins 2a—2k, and found that compounds 2a—2k could converted to its isomers six-membered ring lactam 3a—3k. The structures of compounds 2a—2k were confirmed by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. Antibacterial activity tests showed that compounds 2a—2k had good antibacterial activity against Candida albicans, Cryptococcus neoformans(standard and clinical), E. coli and B. subtilis. While compounds 3a—3k had no activities of the measured strains. It was noteworthy that the mixtures of compounds 2a—2e and 3a—3e had better antifungal effects than those of compounds 2a—2e single, the presence of compound 3a—3e enhanced the antibacterial activities of compounds 2a—2e.

Key words: α,β,-Unsaturated carboxylic acid, 1,5-Benzothiazepine, Antibacterical activity