Synthesis and Antifungal Activity of N-(Substituted pyridinyl)-1-methyl(phenyl)-3-(trifluoromethyl)-1H-pyrazole-4-carboxamide Derivatives

A series of N-(substituted pyridinyl)-1-methyl(phenyl)-3-trifluoromethyl-1H-pyrazole-4-carboxamide derivatives were synthesized. All target compounds were characterized by spectral data (¹H-NMR, ¹³C-NMR, IR, MS) and elemental analysis and were bioassayed in vitro against three kinds of phytopathogenic fungi (Gibberella zeae, Fusarium oxysporum, Cytospora mandshurica). The results showed that some of the synthesized N-(substituted pyridinyl)-1-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxamides exhibited moderate antifungal activities, among which compounds 6a, 6b and 6c displayed more than 50% inhibition activities against G. zeae at 100 µg/mL, which was better than that of the commercial fungicides carboxin and boscalid.