Synthesis and bioactivities of novel 2-(thioether/sulfone)-5-pyrazolyl-1,3,4-oxadiazole derivatives

By introducing the pyrazole moiety into the 5-position of 1,3,4-oxadiazole, a series of novel 2-(thioether/sulfone)-5-pyrazolyl-1,3,4-oxadiazole derivatives were synthesized. Among them, the EC50 values of 6c, 7a, 7b and 7c against Xanthomonas oryzae pv. oryzae were within 16.6 and 65.7 μg/mL, which were better than those of commercial agricultural antibacterial product bismerthiazol and thiodiazole copper. While compounds 7a, 7b, and 7c exerted comprehensive antifungal activity toward five plant fungi, which were comparable with that of hymexazol.