Synthesis, Insecticidal Activities, and SAR Studies of Novel Pyridylpyrazole Acid Derivatives Based on Amide Bridge Modification of Anthranilic Diamide Insecticides

Anthranilic diamides are one of the most important classes of modern agricultural insecticides. To discover new structure-modified compounds with high activity, series of novel carbonyl thioureas, carbonyl ureas, oxadiazoles, carbonyl thiophosphorylureas, oxadiazole-containing amides, and thiazoline-containing amides were designed through the modification of the amide bridge based on the structure of chlorantraniliprole and were synthesized, and bioassays were carried out. The compounds were characterized and confirmed by melting point, IR, (1)H NMR, and elemental analyses or HRMS. Preliminary bioassays indicated that some compounds exhibited significant insecticidal activities against oriental armyworm, diamondback moth, beet armyworm, corn borer, and mosquito. Among them, trifluoroethoxyl-containing carbonyl thiourea 20a showed best larvicidal activity against oriental armyworm, with LC50 and LC95 values of 0.1812 and 0.7767 mg/L, respectively. Meanwhile, 20c and 20e showed 86 and 57% death rates against diamondback moth at 0.005 mg/L, and the LC50 values of the two compounds were 0.0017 and 0.0023 mg/L, respectively, which were lower than that of the control chlorantraniliprole. The relationship between structure and insecticidal activity was discussed, and the HF calculation results indicated that the carbonyl thiourea moiety plays an important role in the insecticidal activity. The present work demonstrated that the trifluoroethoxyl-containing carbonyl thioureas can be used as lead compounds for further development of novel insecticides.