Synthesis and antifungal activity of novel sulfoxide derivatives containing trimethoxyphenyl substituted 1,3,4-thiadiazole and 1,3,4-oxadiazole moiety Original Research Article

Selective oxidation of sulfides 7 or 8 to sulfoxides 9 or 10 is achieved by mCPBA. The structures of the compounds 9 or 10 are confirmed by elemental analysis, IR, and 1H NMR. The bioassay results showed that title compound 10a possess high antifungal activities with EC50 values ranging from 19.91 to 63.97 μg/mL. The mechanism of action of 10a against Sclerotinia sclerotiorum was studied. After treating with compound 10a at 100 μg/mL for 12 h, the mycelial reducing sugar, d-GlcNAc, soluble protein and pyruvate content, chitinase activity showed declining tendency.