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

Thirteen novel (E)-alpha-(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.