Metabolites of bird's nest fungi. Part 5. The isolation of 1-hydroxy-6-methyl-8-hydroxymethylxanthone, a new xanthone, from Cyathus intermedius. Synthesis via photoenolisation

Abstract

The structure of 1-hydroxy-6-methyl-8-hydroxymethylxanthone, a new xanthone isolated from the culture broth of Cyathus intermedius, has been confirmed by synthesis. Regioselective hydroxylation of the 8-methyl of 1-hydroxy-6,8-dimethylxanthone was achieved via the peroxide formed by reaction of oxygen with the photoenol, and also via bromination of the photoenol. Extraction of the mycelia of C. intermedius yielded ergosterol and D-mannitol.