Design, synthesis, and bioactivities of novel oxadiazole-substituted pyrazole oximes

Abstract

A series of novel pyrazole oxime derivatives containing a substituted oxadiazole group were designed and synthesized. The bioassay results indicated that some title compounds displayed good acaricidal and insecticidal activities against Tetranychus cinnabarinus, Aphis medicaginis, Oriental armyworm, and Nilaparvata lugens. Especially, compounds 7a, 7b, and 7c had 80%, 90%, and 90% insecticidal activities against A. medicaginis at 20μg/mL, respectively. Interestingly, some of the designed compounds displayed wonderful fungicidal activities in vivo against cucumber Pseudoperonospora cubensis. Furthermore, compounds 7a (EC₅₀=4.97μg/mL) and 7h (EC₅₀=0.51μg/mL) showed excellent fungicidal activity against P. cubensis comparable or better than that of the control Pyraclostrobin (EC₅₀=4.59μg/mL).

Keywords: Biological activity; Oxadiazole; Pyrazole oxime; Synthesis.