Natural acetylenes. Part XXVII. An antifungal acetylenic furanoid keto-ester (wyerone) from shoots of the broad bean (Vicia faba L.; Fam. Papilionaceae)

Abstract

The isolation and determination of the structure of the fungitoxic principle of the broad bean, Vicia faba L., is described. The natural material is the acetylenic keto-ester R[graphic omitted]·CH[graphic omitted]CH·CO₂Me (R =cis-EtCH:CH·C⋮C·CO), contaminated with about 2% of the more saturated ketone (R = BuC⋮C·CO). In addition, the alcohol (R =cis-EtCH:CH·C⋮C·CHOH) was found in the shoot extract. These compounds, as well as the lower homologue (R =cis-MeCH:CH·C⋮C·CO), its trans-isomer, the aldehyde (R = OCH·C⋮C), the alcohol (R = HO·CH₂·C⋮C), and the close thiophen analogue MeCH[graphic omitted]CH·C⋮C·CO·[graphic omitted]·CH[graphic omitted]CH·CO₂Me were synthesised, and their fungitoxic properties were compared.