Synthesis and biological activities of novel trifluoromethylpyridine amide derivatives containing sulfur moieties

A series of trifluoromethylpyridine amide derivatives containing sulfur moieties (thioether, sulfone and sulfoxide) was designed and synthesized. Their antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo), Ralstonia solanacearum (R. solanacearum) and insecticidal activities against P. xylostella were evaluated. Notably, the half-maximal effective concentration (EC₅₀) value of sulfone-containing compound F10 is 83 mg L^-1 against Xoo, which is better than that of commercial thiodiazole copper (97 mg L^-1) and bismerthiazol (112 mg L^-1). Thioether-containing compounds E1, E3, E5, E6, E10, E11 and E13 showed much higher activities against R. solanacearum with the EC₅₀ value from 40 to 78 mg L^-1, which are much lower than that of thiodiazole copper (87 mg L^-1) and bismerthiazol (124 mg L^-1). Generally, most of the sulfone-containing compounds and sulfoxide-containing compounds showed higher activities against Xoo than that of the corresponding thioether-containing compound, but most of the thioether-containing compounds contributed higher antibacterial activities against R. solanacearum. Furthermore, title compounds E3, E11, E24 and G2 showed good insecticidal activities of 75%, 70%, 70% and 75%, respectively.