Design, synthesis, and antibacterial activity of novel thiochromanone derivatives containing an acylhydrazone moiety

In this study, a series of novel thiochromanone derivatives containing an acylhydrazone moiety were designed and synthesized. Their structures were characterized by 1H NMR, 13C NMR, and HRMS. Bioassay results indicated that most of the target compounds exhibited good in vitro antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas oryzae pv. oryzicolaby (Xoc), and Xanthomonas axonopodis pv. citri (Xac). Especially, compound methyl 6-chloro-4-(2-(4-fluorobenzoyl)hydrazineylidene)thiochromane-2-carboxylate (4f) revealed the best antibacterial activities against Xoo, Xoc, and Xac, with the EC50 values of 15, 28, and 24 μg/mL, respectively, compared with Bismerthiazol and Thiodiazole copper. As far as we know, this is the first report on the antibacterial activity of this series of novel thiochromanone derivatives containing an acylhydrazone moiety.