Biosynthetic origin and revised structure of ascochitine, a phytotoxic fungal metabolite. Incorporation of [1-13C]- and [1,2-13C2]-acetates and [Me-13C]methionine
Abstract
A 13C, n.m.r. analysis of [1-13C]- and [1,2-13C2]-acetate- and [Me-13C] methionine-derived ascochitine confirms its origin from a single hexaketide chain and three Cl units. An ortho-quinone-methide structure is assigned on the basis of the 13C–1H n.m.r. coupling patterns.