Design, synthesis, and acaricidal/insecticidal activity of novel nicofluprole compounds

To discover novel phenylpyrazole acaricides/insecticides with enhanced activity and structural diversity, a series of 14 nicofluprole derivatives were designed and synthesized through pharmacophore fusion strategy using nicofluprole as the lead compound. The structures of target compounds were confirmed by ¹H NMR, ¹³C NMR, and HRMS. Acaricidal/insecticidal activities against Tetranychus cinnabarinus, Plutella xylostella, and Mythimna separata were systematically evaluated. Bioassay results revealed that several compounds exhibited over 85% mortality against T. cinnabarinus at a concentration of 4 mg/L. Notably, compounds 7a and 7b demonstrated superior acaricidal activities of 93.7% and 89.5% respectively, showing significant improvement compared to the parent compound nicofluprole. These compounds could serve as promising lead candidates for further investigation. Additionally, the preliminary structure-activity relationship analysis based on the bioassay data provided theoretical guidance for subsequent research and development of related acaricides/insecticides.