Trihydroxyanthraquinone

A trihydroxyanthraquinone or trihydroxyanthracenedione is any of several isomeric organic compounds with formula, formally derived from anthraquinone by replacing three hydrogen atoms by hydroxyl groups. They include several historically important dyes. The isomers may differ in the parent anthraquinone isomer and/or of the three hydroxyl groups.

In general there are 56 ways of choosing three out of the 8 hydrogens. However, if the underlying core is symmetrical, some of these choices will give identical molecules.

From 9,10-anthraquinone
Due to the symmetry of the 9,10-anthraquinone core, there are only 14 isomers.


 * 1,2,3-Trihydroxyanthraquinone (anthragallol)
 * 1,2,4-Trihydroxyanthraquinone (purpurin), a component of madder root dye.
 * 1,2,5-Trihydroxyanthraquinone (oxyanthrarufin)
 * 1,2,6-Trihydroxyanthraquinone (flavopurpurin)
 * 1,2,7-Trihydroxyanthraquinone (isopurpurin, anthrapurpurin)
 * 1,2,8-Trihydroxyanthraquinone (oxychrysazin)
 * 1,3,5-Trihydroxyanthraquinone
 * 1,3,6-Trihydroxyanthraquinone
 * 1,3,7-Trihydroxyanthraquinone
 * 1,3,8-Trihydroxyanthraquinone
 * 1,4,5-Trihydroxyanthraquinone
 * 1,4,6-Trihydroxyanthraquinone
 * 1,6,7-Trihydroxyanthraquinone
 * 2,3,6-Trihydroxyanthraquinone