Naphthazarin, often called 5,8-dihydroxy-1,4-naphthoquinone or 5,8-dihydroxy-1,4-naphthalenedione (IUPAC), is a naturally occurring[1][2] organic compound with formula C
10H
6O
4, formally derived from 1,4-naphthoquinone through replacement of two hydrogen atoms by hydroxyl (OH) groups. It is thus one of many dihydroxynaphthoquinone structural isomers.

Naphthazarin is soluble in 1,4-dioxane from which it crystallizes as deep red needles that melt at 228−232 °C.[3]

Synthesis

Naphtharazin can be prepared by condensation of 1,4-dimethoxybenzene with 2,3-dichloromaleic anhydride followed by reductive dechlorination and reoxidation.[4][5]

Naphtharazin can also be obtained by oxidation of 5,8-dihydroxy-1-tetralone with manganese dioxide (MnO2).[3]

References

  1. ^ Thomson R.H. Naturally Occurring Quinones. Academic Press, London (1971). Quoted by Khalafy and Bruce.
  2. ^ Thomson R.H. Naturally Occurring Quinones III. Chapman and Hall, London (1987). Quoted by Khalafy and Bruce.
  3. ^ a b 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.
  4. ^ Lewis J.R. and Paul J.J.(1977). Z. Naturforsch., B, 32: 1473. Quoted by Khalafy and Bruce.
  5. ^ Huot R. and Brassard P. (1974). Can. J. Chem., 52: 838. Quoted by Khalafy and Bruce.