Investigations on fungicides. XX. The fungitoxicity of analogues of the phy toalexin 2‐(2‘ ‐methoxy‐4’ ‐hydroxyphenyl)‐6‐methoxybenzofuran(vignafuran)

SUMMARY A series of hydroxy‐and methoxy‐2‐phenyl benzofurans, structurally related to the phytoalexin vignafuran, have been synthesised and their antifungal activity assessed both as inhibitors of spore germination in vitro and as protective foliar sprays against three pathogens. All fungitoxic compounds have a hydroxy group in the molecule although most di‐ and tri‐hydroxy compounds were inactive. Methoxy compounds were inactive but substituting methoxy groups into the molecule of monohydroxy compounds sometimes enhanced their fungitoxicity. No close correlation was established between antifungal activity and either Hansen n values or the n.m.r. chemical shift of the phenolic protons.