A dihydroxynaphthoquinone (formula: ) is any of several
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 that can be viewed as derivatives of
naphthoquinone
Naphthoquinones constitute a class of organic compounds structurally related to naphthalene. Two isomers are common for the parent naphthoquinones:
* 1,2-Naphthoquinone
* 1,4-Naphthoquinone
Natural products
* Alkannin
* Hexahydroxy-1,4-nap ...
through replacement of 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 (H) 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 (OH).
The unqualified term "dihydroxynaphthoquinone" usually means a derivative of
1,4-naphthoquinone
1,4-Naphthoquinone or para-naphthoquinone is a quinone derived from naphthalene. It forms volatile yellow triclinic crystals and has a sharp odor similar to benzoquinone. It is almost insoluble in cold water, slightly soluble in petroleum ethe ...
. Other dihydroxy- compounds can be derived from the two other known isomers,
1,2-naphthoquinone
1,2-Naphthoquinone or ''ortho''-naphthoquinone is a polycyclic aromatic organic compound with formula . This yellow solid is prepared by oxidation of 1-amino-2-hydroxynaphthalene with ferric chloride.
Occurrence
This diketone (an ortho-quinone) ...
(''ortho''-) and
2,6-naphthoquinone (''amphi''-).
Isomers
From 1,4-naphthoquinone
Due to the symmetry of the parent quinone, there are only nine distinct isomers of dihydroxy-1,4-naphthoquinone:
*
2,3-Dihydroxy-1,4-naphthoquinone.
*
2,5-Dihydroxy-1,4-naphthoquinone.
*
2,6-Dihydroxy-1,4-naphthoquinone.
*
2,7-Dihydroxy-1,4-naphthoquinone.
*
2,8-Dihydroxy-1,4-naphthoquinone.
*
5,6-Dihydroxy-1,4-naphthoquinone.
*
5,7-Dihydroxy-1,4-naphthoquinone.
*
5,8-Dihydroxy-1,4-naphthoquinone (naphthazarin).
[
J. Khalafy and J.M. Bruce (2002), ''Oxidative dehydrogenation of 1-tetralones: Synthesis of juglone, naphthazarin, and α-hydroxyanthraquinones''. Journal of Sciences, Islamic Republic of Iran, volume 13 issue 2, pages 131-139.
]
*
6,7-Dihydroxy-1,4-naphthoquinone.
From 1,2-naphthoquinone
From 1,2-naphthoquinone there are 12 possible dihydroxy- isomers:
*
3,4-Dihydroxy-1,2-naphthoquinone
*
3,5-Dihydroxy-1,2-naphthoquinone
*
3,6-Dihydroxy-1,2-naphthoquinone
*
3,7-Dihydroxy-1,2-naphthoquinone
*
3,8-Dihydroxy-1,2-naphthoquinone
*
4,5-Dihydroxy-1,2-naphthoquinone
*
4,6-Dihydroxy-1,2-naphthoquinone
*
4,7-Dihydroxy-1,2-naphthoquinone
*
4,8-Dihydroxy-1,2-naphthoquinone
*
5,6-Dihydroxy-1,2-naphthoquinone
*
5,7-Dihydroxy-1,2-naphthoquinone
*
5,8-Dihydroxy-1,2-naphthoquinone
*
6,7-Dihydroxy-1,2-naphthoquinone
*
6,8-Dihydroxy-1,2-naphthoquinone
*
7,8-Dihydroxy-1,2-naphthoquinone
From 2,6-naphthoquinone
From the symmetrical 2,6-naphthoquinone there are only nine dihydroxy- isomers:
*
1,3-Dihydroxy-2,6-naphthoquinone
*
1,4-Dihydroxy-2,6-naphthoquinone
*
1,5-Dihydroxy-2,6-naphthoquinone
*
1,7-Dihydroxy-2,6-naphthoquinone
*
1,8-Dihydroxy-2,6-naphthoquinone
*
3,4-Dihydroxy-2,6-naphthoquinone
*
3,7-Dihydroxy-2,6-naphthoquinone
*
3,8-Dihydroxy-2,6-naphthoquinone
*
4,8-Dihydroxy-2,6-naphthoquinone
See also
*
Hydroxynaphthoquinone A hydroxynaphthoquinone (formula: ) is any of several organic compounds that can be viewed as derivatives of a naphthoquinone through replacement of one hydrogen atom (H) by a hydroxyl group (-OH).
In general, the term may mean any naphthoquinone d ...
*
Trihydroxynaphthoquinone
*
Dihydroxyanthraquinone A dihydroxyanthraquinone is any of several isomeric organic compounds with formula , formally derived from 9,10-anthraquinone by replacing two hydrogen atoms by hydroxyl groups. Dihyroxyantraquinones have been studied since the early 1900s, and in ...
References
{{reflist
Hydroxynaphthoquinones