Studies on fungal metabolites. Part 2. Carbon-13 nuclear magnetic resonance biosynthetic studies on pentaketide metabolites of Aspergillus melleus: 3-(1,2-epoxypropyl)-5,6-dihydro-5-hydroxy-6-methylpyran-2-one and mellein
The 13C n.m.r. spectra and incorporations of 13C-labelled precursors into pyrone and dihydroisocoumarin pentaketide metabolites from the culture liquors of Aspergillus melleus are reported. Detection of a two-bond 13C–13C coupling in a metabolite enriched from [1,2-13C2]acetate provides proof for an intramolecular rearrangement occurring during biosynthesis.