Synthesis and Biological Activity of Novel 5-Aryl-N-pyrazole Oxime Ester Derivatives

4-(2-Hydroxyphenyl)but-3-en-2-one was prepared from 2-hydroxybenzaldehyde, which then reacted with hydrazine monohydrate.Ten new 1-(5-(2-hydroxy)phenyl)-3-methy-4,5-dihydropyrazol-1-yl) ethanone oxime ester derivatives were synthesized and characterized by elemental analysis, IR and 1H NMR. The compounds were evaluated for their fungicidal activity. The results showed that the title compounds displayed good fungicidal activity against Gibberella(inhibition ratio of compounds 5f towards Gibberella at 50 mg/L was 81.3%); compounds 5g and 5i showed certain fungicidal activity against H.Oryzae. The title compounds showed poor fungicidal activity against P.oryza.