Pigments of fungi. Part 51. Structure and stereochemistry of coupled pre-anthraquinones of the pseudophlegmacin type from Australian toadstools belonging to the genus Dermocybe

(3'R,P)-Anhydropseudophlegmacin-9,10-quinone 6',8'-di-O-methyl ether 4 and the corresponding 1,6',8'-tri-O-methyl ether 5 are isolated together with t he atropisomeric green pigments austroviridin B 10 and austroviridin A 11 f rom the fruiting bodies of indigenous Australian toadstools belonging to th e genus Dermocybe. The structures of these pigments are determined by spect roscopic methods, while their absolute configurations are established from the respective CD spectra and by reductive cleavage of 5 to a mixture of (R )-torosachrysone 8-O-methyl ether 12 and emodin 1-O-methyl ether 14.