Synthesis and Antifungal Activity of 1,2,4-Oxadiazole Derivatives.

1,2,4-Oxadiazole derivatives containing anisic acid or cinnamic acid were designed and synthesized, which were expected to be an effective Succinate dehydrogenase (SDH) inhibitor, and their structures were characterized by H NMR, C NMR, and ESI-MS. The antifungal activity of the compounds against plant pathogenic fungi was screened by the mycelial growth inhibition test in vitro. Compounds and showed significant antifungal activities against , , , and . The values of were 38.88 μg/mL, 149.26 μg/mL, 228.99 μg/mL, and 41.67 μg/mL against , , , and , respectively, and the values of were 12.68 μg/mL, 29.97 μg/mL, 29.14 μg/mL, and 8.81 μg/mL, respectively. Compound was better than commercial carbendazim against . Compounds and showed an antifungal effect on of capsicum in vivo. Molecular docking simulation showed that and interacted with the target protein through the hydrogen bond and hydrophobic interaction, in which can form hydrogen bonds with TRP173 and ILE27 of SDH, and had hydrogen bonds with TYR58, TRP173, and SER39. This also explains the possible mechanism of action between the inhibitor and target protein.