A dihydroxyanthraquinone is any of several isomeric organic compounds with formula (C12H6(OH)2)(CO)2, formally derived from 9,10-anthraquinone by replacing two hydrogen atoms by hydroxyl groups.
Dihyroxyantraquinones have been studied since the early 1900s, and include some compounds of historical and current importance.
[1][2] The isomers differ in the position of the hydroxyl groups, and of the carbonyl oxygens (=O) of the underlying anthraquinone.
The dihydroxy-9,10-anthraquinone functional group occurs widely in natural products,[3][4][5] and is an important feature of the anthracycline antitumour antibiotics.
[6][7] In particular, 1,8-Dihydroxy-9,10-anthraquinone is the precursor for the important topical antipsoriatic drug anthralin, 1,8-dihydroxy-9-anthrone,[8][9] There are 28 ways of choosing two of the 8 possible hydrogens, but because of the four-fold symmetry of the 9,10-anthraquinone core there are only 10 distinct isomers.