Design, Synthesis, and Insecticidal Activities of Imidazo[4,5‐b]Pyridine Compounds Containing Uracil Fragment

ABSTRACT As a novel class of nitrogen‐containing heterocyclic compounds, imidazopyridine uracils serve as the core scaffold in this study, where 16 derivatives were designed and synthesized with oxazosulfuron as the lead compound. The chemical structures of the target compounds were fully characterized and confirmed by proton nuclear magnetic resonance spectroscopy ( 1 H NMR ), carbon‐13 nuclear magnetic resonance spectroscopy ( 13 C NMR ), and high‐resolution mass spectrometry ( HRMS ). Nilaparvata lugens , Plutella xylostella , and Mythimna separata were selected as the test insects, and the insecticidal activities of the target compounds were determined in this research. Especially, compound 8a showed a mortality rate of 77.8% against N. lugens at 10 mg/L, which was superior to the activity of oxazosulfyl under the same conditions (51.9% mortality at 10 mg/L). In addition, compound 9j exhibited a mortality rate of 25.0% against M. separata at a concentration of 1 mg/L, which was superior to that of oxazosulfyl under the same conditions (0% mortality at 1 mg/L). This study is intended to provide a theoretical reference for the subsequent research and industrial development of this class of novel insecticides.