Design, synthesis and insecticidal evaluation of novel N-pyridylpyrazolecarboxamide derivatives containing isoxazole, isoxazoline and 1,3,4-thiadiazole rings

With the introduction of various heterocyclic rings at the benzene part of anthranilic diamides, a series of N-pyridylpyrazolecarboxamide derivatives containing isoxazole, isoxazoline and 1,3,4-thiadiazole rings was designed, synthesized and evaluated for their insecticidal activities. The structures of the obtained novel target compounds were confirmed by means of 1H NMR, 13C NMR and HRMS. The bioassay results indicated that most of the target compounds displayed moderate or good insecticidal activities against oriental armyworm and diamondback moth at the adopted concentrations compared with chlorantraniliprole, especially compounds Ii and Il, of which the LC50 and LC95 values against oriental armyworm were further measured. The structure-activity relationship demonstrated that the introduction of chlorine in benzene ring, bromomethyl and acetoxyl substituents in 4,5-dihydroisoxazole part was more advantageous to improve the corresponding insecticidal activities than the introduction of other substituents and heterocycles.