Microwave synthesis and biological activity of 2-phenyl-5-aryl-1,3,4-oxadiazoles

The reaction of substituted aryl hydrazides with benzoic acid in the presence of dehydrating agent POCl3, affords a series of 2,5-aryl-1,3,4-oxadiazoles under microwave irradiation (MWI). 2,5-Disubstituted-1,3,4-oxadiazoles have attracted much attention due to their diverse biological activities. Compared with classical methods, this method has the advantages of high yields; short reaction time, easy preparation. The preliminary biological test showed that-the synthesized compound has weak-activity to G. zeae Petch, B. cinerea Pers, Phytophthora infestans (Mont.) de Bary, Botryosphaeria berengeriana f. sp. piricola (Nose) koganezawa et Sakuma, Fusarium oxysporum f.sp. cucumerinum and Cercospora arachidicola. The structures of compounds were characterized by melting points, H-1 NMR and IR.