Pigments of fungi.: Part 50.: Structure, biosynthesis and stereochemistry of new dimeric dihydroanthracenones of the phlegmacin type from Cortinarius sinapicolor Cleland

(3S,3'S,P)-Anhydrophlegmacin-9,10-quinon 8'-O-methyl ether 2 and its (2'S)-hydroxy derivative 3 are isolated from the bright yellow, glutinous fruiting bodies of the Australian toadstool Cortinarius sinapicolor and their structures and absolute stereochemistry are deduced by spectroscopic, chemical and isotopic labelling methods. The biosynthesis of the phlegmacin derivatives 2 and 3 in C. sinapicolor has been studied by feeding experiments using sodium [2-C-13]acetate, [Me-C-13]methionine and 6-O-[Me-C-13]-torosachrysone 8-O-beta-D-gentiobioside 5.