Naphthazarin

Naphthazarin
Names
	Preferred IUPAC name 5,8-Dihydroxynaphthalene-1,4-dione
	Other names Dihydroxynaphthoquinone
Identifiers
CAS Number	475-38-7 ;
3D model (JSmol)	Interactive image; Interactive image;
ChEBI	CHEBI:28849 ;
ChEMBL	ChEMBL274056 ;
ChemSpider	9735 ;
ECHA InfoCard	100.006.816
EC Number	207-495-4;
KEGG	C01938;
PubChem CID	10141;
UNII	S9IX5I5C0K;
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)
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H312, H315, H319, H332, H335
Precautionary statements	P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P312, P321, P322, P330, P332+P313, P337+P313, P362, P363, P403+P233, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) 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]

^ 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.
^ ^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.
^ 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.