Design, synthesis, insecticidal activities and binding mode with γ-aminobutyric acid receptor of pyrazolopyrimidine derivatives

Twenty-five novel phenylpyrazole-pyrimidinamine and phenylpyrazole-pyrimidinone compounds were designed and synthesized based on the low-energy conformation of fipronil using scaffold hopping strategy. Their structures were confirmed by ¹H NMR, ¹³C NMR and HRMS. The insecticidal activity study indicated that compounds A5 , B1 , B4 and B5 showed 40%-73% mortality to Plutella xylostella at 500 mg/L. However, the insecticidal activities were still weaker than that of fipronil. The differences in physicochemical properties and binding mode with insectival γ-aminobutyric acid (GABA) receptor between these compounds and fipronil may be the major factor which reduced the insecticidal activities.