Cortinaric Acid

Acidic anthraquinones in which both hydroxy groups in the C-ring have been methylated occur in Cortinarius armillatus and C. miniatopus, while cortinaric acid (313) and its 8-0-methyl ether (314) have been isolated from Cortinarius elegantior where they are partly responsible for the characteristic pink colour produced in the stem base with ammonia. The structures of the latter pigments have been confirmed by synthesis involving chromium trioxide oxidation of the peracetyl derivatives of endocrocin (303) and dermolutein (305), respectively 387). 

Cortinaric Acid (313) - 0.28 Orange Brown Dark violet (387)... 

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