A tetrahydroxyanthraquinone, also called tetrahydroxyanthradione, is any of several isomeric organic compounds with formula (C12H4(OH)4)(CO)2, almost invariably derived from 9,10-anthraquinone by replacing four hydrogen atoms by hydroxyl groups.
Only a few of these isomers are commercially significant.
[1] These are 1,2,5,8-tetrahydroxyanthraquinone (quinalizarin), 1,4,5,8-tetrahydroxyanthraquinone, and 1,2,3,4-tetrahydroxyanthraquinone (Alizarine Bordeaux).
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