A dihydroxynaphthoquinone is any of several organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

s with formula , which can be viewed as derivatives of naphthoquinone

Naphthoquinone

Naphthoquinone is a class of natural phenols based on the C6-C4 skeleton.1,4-Naphthoquinone can be viewed as derivatives of naphthalene through the replacement of two hydrogen atoms by two ketone groups....

 through replacement of two hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 atoms (H) by hydroxyl

Hydroxyl

A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...

 groups (OH).

The unqualified term "dihydroxynaphthoquinone" usually means a derivative of 1,4-naphthoquinone. Other dihydroxy- compounds can be derived from the two other known isomers, 1,2-naphthoquinone

1,2-Naphthoquinone

1,2-Naphthoquinone or ortho-naphthoquinone is a polycyclic aromatic organic compound with formula .This double ketone is a reactive metabolite of naphthalene and is found in diesel exhaust particles...

 (ortho-) and 2,6-naphthoquinone (amphi-).

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
  5,8-Dihydroxy-1,4-naphthoquinone
  Naphthazarin, often called 5,8-dihydroxy-1,4-naphthoquinone or 5,8-dihydroxy-1,4-naphthalenedione , is a naturally occurring organic compound with formula , formally derived from 1,4-naphthoquinone through replacement of two hydrogen atoms by hydroxyl groups...
  
   (naphthazarin).
• 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