Synthesis and Insecticidal Activity of Nitenpyram Analogs with Tetrahydropyrimidine Fixed (Z)‐Configuration

Two series of novel (Z)‐nitenpyram analogs 2a , 2b , 2c , 2d , 2e , 2f , 2g , 2h , 3a , 3b , 3c , 3d were synthesized by introducing various amino acids benzyl ester or amino acids tetrahydrofurfur‐2‐yl ester into nitenpyram and forming a tetrahydropyrimidine ring to fix (Z)‐configuration. The structures of the target compounds were characterized by ¹HNMR, MS, IR, and elemental analysis. Preliminary bioassays against Nilaparvata lugens indicated that all the nitenpyram analogs exhibited good insecticidal activity at 100 mg/L, whereas the compounds 3b and 3d afforded the best in vitro inhibitory activities that had ≥ 90% mortality at 20 mg/L.