| Abstract: | A previous investigation established that compounds containing a guanidinium or amidinium grouping are effective inhibitors of sterol Δ8–Δ7 isomerase and/or Δ14 reductase activity in plant pathogenic fungi. A binding model for known fungicidal inhibitors of this enzyme has now been used to rationally design further guanidinium or amidinium inhibitors. Three novel classes of chemistry were investigated. The results of biochemical testing against ergosterol biosynthesis in Ustilago maydis (DC) Corda and of in-vivo testing for fungicidal activity against Erysiphe graminis DC f. sp. hordei Marchal (powdery mildew of barley), do much to support the binding model, and compounds with significant fungicidal activity have been found. © 1997 SCI. |
