Tetrahydroxyanthraquinone

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