Secondary mould metabolites. Part 13. Fungal perylenequinones: phleichrome, isophleichrome, and their endoperoxides
Abstract
The helix-shaped, fungal pigment phleichrome has been isomerized to isophleichrome. The axial chirality and absolute configuration of the side-chain carbons of both perylenequinones have been established. Photo-oxidation of both compounds occurs stereospecifically to give their endoperoxides, whose structure and stereochemistry results from a detailed analysis of their n.m.r. spectra.