5,8-Dihydroxy-1,4-naphthoquinone

5,8-Dihydroxy-1,4-naphthoquinone
IUPAC name 5,8-dihydroxynaphthalene-1,4-dione
Other names Dihydroxynaphthoquinone
Identifiers
PubChem	10141
ChemSpider	9735 Y
ChEMBL	CHEMBL274056 Y
Jmol-3D images	Image 1 Image 2
SMILES C1=CC(=C2C(=O)C=CC(=O)C2=C1O)O O=C\2c1c(O)ccc(O)c1C(=O)/C=C/2
InChI InChI=1S/C10H6O4/c11-5-1-2-6(12)10-8(14)4-3-7(13)9(5)10/h1-4,11-12H Y Key: RQNVIKXOOKXAJQ-UHFFFAOYSA-N Y InChI=1/C10H6O4/c11-5-1-2-6(12)10-8(14)4-3-7(13)9(5)10/h1-4,11-12H Key: RQNVIKXOOKXAJQ-UHFFFAOYAN
Properties
Molecular formula	C10H6O4
Molar mass	190.15 g/mol
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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 C₁₀H₆O₄, 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.