Benzamides Substituted with Quinoline-Linked 1,2,4-Oxadiazole: Synthesis, Biological Activity and Toxicity to Zebrafish Embryo.

To develop new compounds with high activity, broad spectrum and low-toxicity, 17 benzamides substituted with quinoline-linked 1,2,4-oxadiazole were designed using the splicing principle of active substructures and were synthesized. The biological activities were evaluated against 10 fungi, indicating that some of the synthetic compounds showed excellent fungicidal activities. For example, at 50 mg/L, the inhibitory activity of 13 p (3-Cl-4-Cl substituted, 86.1%) against Sclerotinia sclerotiorum was superior to that of quinoxyfen (77.8%), and the inhibitory activity of 13f (3-CF 3 substituted, 77.8%) was comparable to that of quinoxyfen. The fungicidal activities of 13 f and 13 p to Sclerotinia sclerotiorum were better than that of quinoxyfen (14.19 mg/L), with EC 50 of 6.67 mg/L and 5.17 mg/L, respectively. Furthermore, the acute toxicity of 13 p was 19.42 mg/L, classifying it as a low-toxic compound.