A dihydroxynaphthoquinone (formula: C
10H
6O
4) is any of several organic compounds that can be viewed as derivatives of naphthoquinone through replacement of two hydrogen atoms (H) by hydroxyl 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 (ortho-) and 2,6-naphthoquinone (amphi-).
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).
6,7-Dihydroxy-1,4-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 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
