Design, Synthesis, and Fungicidal Activities of Novel Strobilurin Derivatives Containing a Substituted 1,3,4‐Oxadiazole Moiety

ABSTRACT To explore novel structures of strobilurin fungicides, a series of novel strobilurin derivatives featuring a substituted 1,3,4‐oxadiazole in the side chain were synthesized using an intermediate derivatization method and characterized by nuclear magnetic resonance spectroscopy (NMR) and high‐resolution mass spectrometry (HRMS). The reactions involved in the synthesis process include hydrazine hydrolysis, cyclization, nucleophilic substitution reactions. The raw materials required for these reactions are readily available, and the procedures involved in the reaction process are straightforward. The fungicidal activities of the compounds were tested using the inhibition zone method. The inhibition rate of compound 5f on Magnaporthe oryzae was 81.8% at a concentration of 3.125 mg/L, and the EC 50 value (0.3045 mg/L) was better than superior to that of kresoxim‐methyl (0.5247 mg/L).