Design, Synthesis, and Antibacterial Activity of Carbazole Derivatives Containing 1,3,4-Oxadiazole Thioether Moiety

A novel class of eighteen 2-((9H-carbazol-9-yl)methyl)-5-(benzylthio)-1,3,4-oxadiazole derivatives were designed, synthesized and screened for their in vitro antibacterial activities against <i>Pseudomonas syringae pv. Actinidiae (Psa), Xanthomonas oryzae pv. Oryzae (Xoo)</i> and Xanthomonas axonopodis</i> pv. Citri (Xac). Preliminary bioactivity test results indicated that some compounds showed moderate to good inhibitory effects against the tested bacteria at the concentrations of 100 μg/mL and 50 μg/mL. Among them, compounds 2-((9H-carbazol-9-yl)methyl)-5-((2,6-dichloro benzyl) thio)-1,3,4-oxadiazole (5e) and 2-((9H-carbazol-9-yl)methyl)-5-((4-(trifluoromethyl)benzyl)thio)- 1,3,4-oxadiazole (5m) exhibited the best inhibitory effects against <i>Psa, Xoo</i> and <i>Xac</i> than other compounds, which displayed a wide range of antibacterial activities. Further bioactive applications of these molecules are in progress in our laboratories.