Dihydroxyanthraquinone
From Wikipedia, the free encyclopedia
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.
Isomers
From 9,10-anthraquinone
The unqualified term "dihydroxyanthraquinone" usually means a hydroxy derivative of 9,10-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.[10]
- 1,2-Dihydroxyanthraquinone (alizarin)
- 1,3-Dihydroxyanthraquinone (purpuroxanthin, xanthopurpurin)
- 1,4-Dihydroxyanthraquinone (quinizarin)
- 1,5-Dihydroxyanthraquinone (anthrarufin)
- 1,6-Dihydroxyanthraquinone
- 1,7-Dihydroxyanthraquinone
- 1,8-Dihydroxyanthraquinone (dantron, chrysazin)
- 2,3-Dihydroxyanthraquinone (histazarin)
- 2,6-Dihydroxyanthraquinone (anthraflavic acid)
- 2,7-Dihydroxyanthraquinone (isoanthraflavic acid)
From other anthraquinones
There are also many dihydroxy derivatives of other anthraquinones, such as 1,2-anthraquinone, 1,4-anthraquinone, and 2,6-anthraquinone.[10]
See also
- Hydroxyquinone
- Hydroxybenzoquinone
- Hydroxynaphthoquinone
- Hydroxyanthraquinone
- Trihydroxyanthraquinone
- Tetrahydroxyanthraquinone
- Pentahydroxyanthraquinone
- Hexahydroxyanthraquinone
- Heptahydroxyanthraquinone
- Octahydroxyanthraquinone[1]