Synthesis and Fungicidal Activity of 2,5-Disubstituted-1,3,4-oxadiazole Derivatives

A series of new 2,5-disubstituted-1,3,4-oxadiazole derivatives have been designed and synthesized by adding pyridine ring and thiazole ring to the structure of 1,3,4-oxadiazole. The structures of target compounds have been confirmed by H-1 NMR, EI-MS, IR spectroscopy and elemental analyses. The structure of 2-[(6-pyridin-3-yOmethylthio]-5-(pyridin-4-yl)-1,3,4-oxadazole has been determined by single crystal X-ray diffraction. The results of preliminary bioassay indicated that some compounds possess potential fungicidal activities against Fusarium oxyporium, Gibberella zeae, Rhizoctonia solani, Dothiorella gregaria and Colletotrichum gossypii at a dosage of 5.0 X 10(-5) g/mL. The fungicidal activities of 1,3,4-oxadiazole derivatives adding thiazole ring were better than those of those adding pyridine ring.