Design, Synthesis, and Insecticidal Evaluation of N -Pyridylpyrazole Amide Derivatives Containing 4,5-Dihydroisoxazole Amide as Potential Ryanodine Receptor Activators.

Using the 4,5-dihydroisoxazol amide structure to expand the aliphatic amide moiety of chlorantraniliprole, a series of 28 novel N -pyridylpyrazolecarboxamide derivatives containing 4,5-dihydroisoxazol amide fragment were designed and synthesized. All target compounds had been properly characterized and confirmed by 1 H NMR, 13 C NMR, and HRMS, and the effects were evaluated against Mythimna separata ( M. separata ) and Plutella xylostella ( P. xylostella ). The bioassay results indicated that most of the target compounds exhibited good insecticidal activities against M. separata and P. xylostella at 50 mg/L; especially, compound A4 showed an LC 50 value of 3.27 mg/L against M. separata . Calcium imaging experiments indicated that the target compound A4 had a similar mechanism of action to chlorantraniliprole, causing an increase in the cytoplasmic Ca 2+ concentration. The molecular docking revealed the possible binding mode of compound A4 with a ryanodine receptor.