Synthesis and Bioactivity Evaluation of Novel Thiochroman-4-One Derivatives Incorporating Carboxamide and 1, 3, 4-Thiadiazole Thioether Moieties

Abstract

A series of novel thiochroman-4-one derivatives incorporating carboxamide and 1, 3, 4-thiadiazole thioether moieties were synthesized. Bioassay results indicated that the EC50 values of compound 6-chloro-N-(5-(methylthio)-1, 3, 4-thiadiazol-2-yl)-4-oxothiochromane-2-carboxamide (5a) against Xanthomonas oryzae pv. Oryzae (Xoo) and Xanthomonas axonopodis pv. Citri (Xac) were 24 and 30 μg/mL, respectively, which were even better than those of bismerthiazol and thiadiazole copper. Meanwhile, compound 6-methyl-4-oxo-N-(5-(propylthio)-1, 3, 4-thiadiazol-2-yl)thiochromane-2-carboxamide (5m) showed a better antifungal activity against Botrytis cinerea (B. cinerea), with an inhibition rate of 69%, than carbendazim. As far as we know, this is the first report on the antibacterial and antifungal activities of this series of novel thiochroman-4-one derivatives incorporating carboxamide and 1, 3, 4-thiadiazole thioether moieties.