Naphthazarin

Naphthazarin
Names
	IUPAC name 5,8-dihydroxynaphthalene-1,4-dione
	Other names Dihydroxynaphthoquinone
Identifiers
3D model (JSmol)	Interactive image; Interactive image;
ChEBI	CHEBI:28849 ;
ChEMBL	ChEMBL274056 ;
ChemSpider	9735 ;
ECHA InfoCard	100.006.816
PubChem CID	10141;
CompTox Dashboard (EPA)	DTXSID00197161 ;
	InChI InChI=1S/C10H6O4/c11-5-1-2-6(12)10-8(14)4-3-7(13)9(5)10/h1-4,11-12H Key: RQNVIKXOOKXAJQ-UHFFFAOYSA-N ; 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;
	SMILES C1=CC(=C2C(=O)C=CC(=O)C2=C1O)O; O=C\2c1c(O)ccc(O)c1C(=O)/C=C/2;
Properties
Chemical formula	C10H6O4
Molar mass	190.154 g·mol−1
Melting point	228–232 °C (442–450 °F; 501–505 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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	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 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

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

[thomson71-1] Thomson R.H. Naturally Occurring Quinones. Academic Press, London (1971). Quoted by Khalafy and Bruce.

[thomson87-2] Thomson R.H. Naturally Occurring Quinones III. Chapman and Hall, London (1987). Quoted by Khalafy and Bruce.

[khalafy-3] 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.

[lewis-4] Lewis J.R. and Paul J.J.(1977). Z. Naturforsch., B, 32: 1473. Quoted by Khalafy and Bruce.

[huot-5] Huot R. and Brassard P. (1974). Can. J. Chem., 52: 838. Quoted by Khalafy and Bruce.