Ten 5-pyrazolecarboxamide derivatives were synthesized by the reaction of amine and intermediate 6 starting from 2,3-dichloropyridine and diethyl maleate. Their structures were identified by elemental analysis, IR, ¹H NMR and ¹³C NMR spectra. The preliminary bioassay showed that compounds 7a～7j had moderate insecticidal activities against Nilaparvata lugens (Stal), 7a and 7d possessed good insecticidal ac- tivity with the mortality rate of 57.6% and 64.4% at a concentration of 100 μg/mL, respectively, similarly to the control (buprofezin). Insecticidal mechanism of 7d indicated that it has a good inhibitive activity against Brown planthopper acetylcholinesterase with rate of 75.2% than the commercial control buprofezin (52.2%).

Key words: pyrazolecarboxamide derivative, acetylcholinesterase, synthesis, insecticidal activity