Design, Synthesis and Antifungal Evaluation of N-Substituted-1-(3-chloropyridin-2-yl)-N-(pyridin-4-yl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxamide Derivatives

A series of 1-(3-chloropyridin-2-yl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxamide derivatives which have di-substituents on nitrogen were designed and synthesized. Bioassay results showed that all the synthetic compounds exhibited lower antifungal activities against Gibberella zeae, Cytospora mandshurica, and Fusarium oxysporum than T-3 (14.7, 21.1, and 32.7 mu g/mL), but some of them exhibited better activities against Botrytis cinerea, Phytophthora infestans, and Sclerotinia sclerotiorum than T-3 (>200, >200, and >200 mu g/mL); the EC50 values of 7d and 7c against B. cinerea were 94.9 and 56.2 mu g/mL, respectively. The EC50 values of 7a, 7d, and 7c against S. sclerotiorum were 73.5, 78.7, and 68.5 mu g/mL, respectively.