Design, synthesis and insecticidal‐activity evaluation of N ‐pyridylpyrazolo‐5‐methyl amines and its derivatives

In searching for novel insecticidal leads, a series of N ‐pyridylpyrazolo‐5‐methyl amines and their derivatives were designed and synthesized. Among the 22 target compounds obtained, bioassays indicated that some of the target compounds exhibited good insecticidal activities against Plutella xylostella ( P. xylostella ) and Spodoptera frugiperda ( S. frugiperda ). In particular, compound 9j revealed the best insecticidal activity against P. xylostella , with a LC 50 value of 22.11 mg/L, and compound 9q had the best insecticidal activity against S. frugiperda which with 73.99% of mortality rate at 100 mg/L. Structure‐activity relationship (SAR) analysis showed that 4‐CF 3 at the position of R 1 linked with N ‐pyridylpyrazole via amide bond could enhance the insecticidal activity of the target compounds. This study provides valuable clues for the further design and optimization of N ‐pyridylpyrazole derivatives.