1,3,4-Oxadiazole derivatives were reported to possess a broad spectrum of biological activities, such as antifungal, antibacterial, antiviral and antitubercular. Mannich bases had also been reported as potential biological agents, they were applicated in the fields of synthetic study and medicinal chemistry. In recent years, Mannich bases containing 1,3,4-oxadiazole ring had attracted a lot of attention and many Mannich bases of 1,3,4-oxadiazole bearing heterocycle scaffold were reported to have special bioactivity. Nevertheless, literature revealed that there were no reports of a molecular scaffold that Mannich base of 1,3,4-oxadiazole bearing pyrimidine. Prompted by these observations, a series of 1,3,4-oxadiazole derivatives containing pyrimidine(E1—E15) was synthesized from 5-aryl-1,3,4-oxadiazole-2-thione(C1—C3), formaldehyde and substituted aminopyrimidine(D1—D5) by Mannich reaction. 5-Aryl-1,3,4-oxadiazole-2-thione derivatives(C1—C3) were prepared from aromatic acids as the starting material via esterification, hydrazinolysis and cyclization. The structures of all title compounds were confirmed by elemental analysis, IR, 1H NMR techniques. Furthermore, their biological activities to four vegetable pathogens containing Gibberll nicotiancola, Gibberlla saubinetii, Fusarium oxysporium f. sp. niveum, Pythium solani had been tested. The preliminary results indicated that most of the compounds exhibit relatively good fungicidal activities, especially compounds E3 and E8 showed better biological activity than triazolone.
