Dihydroxynaphthoquinone

A dihydroxynaphthoquinone is any of several organic compounds with formula C₁₀H₆O₄, which 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-).

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).^[1]
• 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
• Trihydroxynaphthoquinone
• Dihydroxyanthraquinone

References

1. ^ 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.