Synthesis and structure-insecticidal activity relationship of novel phenylpyrazole carboxylic acid derivatives containing fluorine moiety

Abstract A series of novel phenylpyrazole carboxylic acid derivatives containing fluorine moiety, i.e., diamides 11, simple aryl-bearing amides 12 and acylthioureas 14 were successfully synthesized based on the key fluoro-containing phenylpyrazole acid intermediate. The new compounds were identified and confirmed by melting point, 1H NMR, 13C NMR and elemental analysis or HRMS. The bioassay results indicated that some of the compounds possessed excellent insecticidal activities towards oriental armyworm, diamondback moth and corn borer at low concentrations. For examples, compounds 11a, 11e−g and 14b exhibited remarkable larvicidal activities with LC50 values of 0.13 − 0.39 mg/L and 0.0002 − 0.0014 mg/L against oriental armyworm and diamondback moth, respectively, were comparable with those of the control chlorantraniliprole. Particularly, 11e were found superior to chlorantraniliprole in oriental armyworm tests (LC50: 0.23 mg/L vs. 0.26 mg/L); 11a, 11e, 11f and 14c in diamondback moth tests with LC50 values of 0.0002 mg/L, 0.0002 mg/L, 0.0008 mg/L and 0.0005 mg/L, respectively, were more effective than that of chlorantraniliprole. In addition, 12a also showed a promising insecticidal potential and development/optimization advantage. Compounds 11a, 11e–g, 12a, 14b and 14c could be considered as possible new leading structures for further study. The SAR investigation indicated that the compounds with fluorine motif (e.g., -F, -CF2H, -CF3) held apparently favorable insecticidal potentials, which provided useful guidance for further design/development of new phenylpyrazole-containing agrochemicals.