Pigments of Fungi. LXVI. The Gentiobiosides of (R)- and (S)-Torosachrysone from Australian Toadstools and Methods for Assaying the Enantiomeric Purity of Natural Torosachrysone

Abstract

The diastereoisomeric 8-O--b-gentiobiosides (2) and (10) of (S)- and (R)-torosachrysone (1) and (11), respectively, are isolated in admixture to varying degrees from toadstools belonging to the genera Cortinarius and Dermocybe. (R)-Torosachrysone (11) is characterized for the first time from a fungus and spectroscopic and chromatographic methods are described that show that torosachrysone, as it occurs in several fungi, is anisochiral and its stereochemical composition is species-dependent.