Design, synthesis, antibacterial, and antifungal evaluation of novel 4-chromanone-derived compounds incorporating carboxamide and 1,3,4-thiadiazole thioether moieties

Abstract

A series of novel botanical active component 4-chromanone derivatives incorporating carboxamide and 1,3,4-thiadiazole thioether moieties were synthesized and evaluated for their in vitro antibacterial and activities antifungal against Xanthomonas axonopodis pv. citri (Xac), Xanthomonas oryzae pv. oryzicolaby (Xoc) and Mucor bainieri (M. bainieri), Mucor fragilis (M. fragilis), Trichoderma atroviride (T. atroviride), respectively. Antibacterial screening results suggested that the target compounds showed moderate to good antibacterial activities against Xac and Xoc, to the contrary, had lower inhibitory effects on M. fragilis, M. bainieri, and T. atroviride. Among the target compounds, compound 6-chloro-N-(5-(methylthio)-1,3,4-thiadiazol-2-yl)-4-oxochromane-2-carboxamide (6f) had the best inhibition rates against Xac (85.15% and 72.41%, respectivelty) and Xoc (95.14% and 82.09%) at 200 and 100 μg/mL, which were superior to Bismerthiazol and Thiodiazole copper. As far as we know, it is the first report on the design, synthesis, and bioactivity evaluation of novel 4-chromanone-derived compounds incorporating carboxamide and 1,3,4-thiadiazole thioether moieties.