A dihydroxyanthraquinone is any of several
isomer
In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the exi ...
ic
organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
s with formula , formally derived from
9,10-anthraquinone by replacing two
hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...
atoms by
hydroxyl
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...
groups. Dihyroxyantraquinones have been studied since the early 1900s, and include some compounds of historical and current importance.
The isomers differ in the position of the hydroxyl groups, and of the
carbonyl
In organic chemistry, a carbonyl group is a functional group with the formula , composed of a carbon atom double bond, double-bonded to an oxygen atom, and it is divalent at the C atom. It is common to several classes of organic compounds (such a ...
oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
s (=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
In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...
occurs widely in natural products,
and is an important feature of the anthracycline antitumour antibiotics.
In particular, 1,8-Dihydroxy-9,10-anthraquinone is the precursor for the important topical antipsoriatic drug anthralin, 1,8-dihydroxy-9-anthrone,
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.
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1,2-Dihydroxyanthraquinone (alizarin)
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1,3-Dihydroxyanthraquinone (purpuroxanthin, xanthopurpurin)
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1,4-Dihydroxyanthraquinone (quinizarin)
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1,5-Dihydroxyanthraquinone (anthrarufin)
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1,6-Dihydroxyanthraquinone
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1,7-Dihydroxyanthraquinone
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1,8-Dihydroxyanthraquinone (dantron, chrysazin)
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2,3-Dihydroxyanthraquinone (histazarin)
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2,6-Dihydroxyanthraquinone (anthraflavic acid)
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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.
See also
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Hydroxyquinone
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Hydroxybenzoquinone
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Hydroxynaphthoquinone
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Hydroxyanthraquinone
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Trihydroxyanthraquinone
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Tetrahydroxyanthraquinone
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Pentahydroxyanthraquinone
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Hexahydroxyanthraquinone
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Heptahydroxyanthraquinone
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Octahydroxyanthraquinone
References
{{Anthraquinone