Metabolites of Lachnellula fuscosanguinea (Rehm). Part 2. The structure of lachnellulone

Abstract

Lachnellulone, an antifungal metabolite produced by Lachnellula fuscosanguinea (Rehm) Dennis is shown to possess structure 8. The structure was determined by consideration of the ultraviolet, infrared, 1H and 13C nuclear magnetic resonance, and mass spectra of 8 and its derivatives and was confirmed by an X-ray crystallographic study of lachnellulone p-nitrobenzoate. In solution lachnellulone undergoes facile isomerization to isolachnellulone (9a), which explains the observed mutarotation of 8. The 13C nuclear magnetic resonance spectra of lachnellulone and the related lachnelluloic acid (1) are discussed in some detail. The absolute configuration of lachnellulone has not been determined.