Stereoselective synthesis and antifungal activities of (E)-α-(methoxyimino)benzeneacetate derivatives containing 1,3,5-substituted pyrazole ring

Thirteen novel ( E)- R-( methoxyimino) benzeneacetate derivatives, the analogues of strobilurins, which contain two pharmacophoric substructures of the methyl ( E)- methoxyiminoacetate moiety and 1,3,5-substituted pyrazole ring, were stereoselectively synthesized. It was found that the coupling reaction could give stereoselectively ( E: Z ca. 14: 1) the key intermediate material ( E)- methyl 2-( hydroxyimino)2- o- tolyl acetate ( 2). An X- ray crystallographic structure determination was carried out in a representative product. The preliminary bioassays indicated that all of the compounds 1 showed potent fungicidal activity against Rhizoctonia solani, Botrytis cinereapers, Gibberella zeae, Physalospora piricola, and Bipolaris mayclis.