Design, Synthesis, Antifungal and Antibacterial Activities of N‐phenyl and N‐pyridinyl‐5‐(trifluoromethyl)‐pyrazole‐4‐carboxamide Derivatives

A series of N ‐phenyl and N ‐pyridinyl‐5‐(trifluoromethyl)‐pyrazole carboxamide derivatives ( T 1 – T 25 ) were designed and synthesized. Bioassay results indicated that antifungal and antibacterial activities of title compounds could be obviously improved by placing trifluoromethyl on the 5‐position of the pyrazole ring and substituted 4‐pyridinyl at the amine side of the amide bond. The EC 50 values of T 3 against G ibberella zeae , Cytospora mandshurica , and Fusarium oxysporum were 14.7, 21.1, and 32.7 μg/mL, respectively, better than hymexazol (30.2, 47.3, and 42.5 μg/mL) and carboxin (34.2, >200, and >200 μg/mL). And the EC 50 values of T 6 , T 11 , T 12 , T 15 , T 18 , T 19 , T 23 , and T 25 against rice bacterial leaf blight were 17.0, 21.8, 21.9, 18.6, 16.8, 25.9, 9.4, and 24.4 μg/mL, respectively, much better than bismerthiazol (70.5 μg/mL).