Synthesis and Biological Activity of Novel 2-(Substituted-benzylthio)-5-(4,6-dimethylpyrimidin-2-thiomethyl)-1,3,4-oxadiazoles

In order to find novel biologically active heterocyclic compounds, thirteen new 2-(substitutedbenzylthio)-5-(4,6-dimethylpyrimidin-2-thiomethyl)-1,3,4-oxadiazoles were prepared with thiocarbamide and 2,4-pentanedione as the staring materials via cyclization, etherification, hvdrazination, cyclization and finally a benzylation reaction under microwave irradiation condition. The preliminary bioassay results indicated that some target compounds exhibited good inhibition activity against Colletrotichum acutatum, Colletrotichum gloeosporioides and Colletrotichum fragariae at 50 mu g/mL, and the inhibition rate of the compound with 3-fluoro against Colletrotichum acutatum reached 80.22%. Several compounds also showed that good antileishmanial activities against Leishmania donovani, the IC50 values of those compounds with 3-chloro, 4-bromo, 3-fluoro and 4-tert-butvl substituent respectively were all less than 25 mu g/mL and were more active than the control drug paromomycin.