Trifluoromethylpyridine 1,3,4-Oxadiazole Derivatives: Emerging Scaffolds as Bacterial Agents

A new class of trifluoromethylpyridine 1,3,4-oxadiazole derivatives (6a-6v) was obtained, and their antibacterial activities were evaluated. Some of them exhibited good activity, particularly 6a, which had the highest in vitro activity against Ralstonia solanacearum (R. solanacearum) and Xanthomonas axonopodis pv. citri (Xac). The half-maximal effective concentrations (EC₅₀) were 26.2 and 10.11 μg/mL, respectively, which were lower than those of commercial thiodiazole copper (97.2 and 35.3 μg/mL, respectively). Furthermore, 6q showed much higher activity against Xanthomonas oryzae pv. oryzae (Xoo) with an EC₅₀ value of 7.2 μg/mL; this was superior to bismerthiazol (57.2 μg/mL). Collectively, our findings provide a foundation for the development of trifluoromethylpyridine 1,3,4-oxadiazole derivatives.