In search of novel pyrazole derivatives with bioactivity, a series of 3-met
hyl-1H-pyrazole-4-caboxylic ester derivatives were synthesized via alpha -o
xoketene dithioacetals as starting material, The structures of all compound
s prepared were confirmed by H-1 NMR, IR, MS and elemental analyses. Prelim
inary bioassays indicated that some compounds showed fungicidal activity ag
ainst wheat rust, phoma asparagi and antiviral activity against TMV.