Pigments of fungi. Part 50. Structure, biosynthesis and stereochemistry ofnew 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 fruitin g bodies of the Australian toadstool Cortinarius sinapicolor and their stru ctures and absolute stereochemistry are deduced by spectroscopic, chemical and isotopic labelling methods. The biosynthesis of the phlegmacin derivati ves 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]-torosachryso ne 8-O-beta-D-gentiobioside 5.