Abstract:
To discover new nematicidal and fungicidal compounds with high activity, 1,3,4-thiadiazole and 1,2,4-triazole structures were introduced into imidazo 1,2-a pyridine by using the principle of active substructure splice, with 2-amino-3-chloro-5-trifluoromethyl pyridine as raw material. Twenty-four unreported 8-chloro-6-(trifluoromethyl) imidazo 1,2-a pyridine thiadiazole/triazole derivatives were designed and synthesized, and their structures were confirmed by
1H NMR,
13C NMR and HRMS. The results indicated that all the compounds showed different levels of toxic activity against
Caenorhabditis elegans when the concentration was 100 mg/L. After 48 h, the corrected mortality rates of compounds
9e, 9f, 9i, 9k, 10d and
10h were 94.10%, 84.08%, 93.74%, 91.82%, 92.61% and 88.90%, respectively, which were better than the control agent fosthiazate (60.28%), but lower than fluopyram (100%). The toxicity of the target compound to
Bursaphelenchus xylophilus was not ideal. At a concentration of 100 mg/L, only compounds
9c and
9l exhibited moderate nematicidal activity, with corrected mortality rates of 50.27% and 49.43%, respectively, which were lower than the control agents fosthiazate (52.04%) and fluopyram (96.50%). The results of the fungicidal activity assay by mycelium growth rate method showed that EC
50 values of compounds
9a and
9c were 57.35 and 34.75 mg/L, respectively, which were better than the control agent fluopyram (122.37 mg/L), but lower than carbendazim (0.48 mg/L). The imidazo 1,2-a pyridine thiadiazole/triazole compounds synthesized in this study have certain nematoidal and fungicidal activities, and provide a reference for further exploration of imidazo 1,2-a pyridine compounds.