Naphthazarin, often called 5,8-dihydroxy-1,4-naphthoquinone or 5,8-dihydroxy-1,4-naphthalenedione (IUPAC), is a naturally occurring organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

 with formula , formally derived from 1,4-naphthoquinone through replacement of two hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 atoms by hydroxyl

Hydroxyl

A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...

 (OH) groups. It is thus one of many dihydroxynaphthoquinone

Dihydroxynaphthoquinone

A dihydroxynaphthoquinone is any of several organic compounds with formula , which can be viewed as derivatives of naphthoquinone through replacement of two hydrogen atoms by hydroxyl groups ....

 structural isomers.

Naphthazarin is soluble in 1,4-dioxane

1,4-Dioxane

1,4-Dioxane, often called dioxane because the other isomers of dioxane are rare, is a heterocyclic organic compound. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. It is classified as an ether. This colorless liquid is mainly used as a stabilizer for the solvent...

 from which it crystallizes as deep red needles that melt at 228-232°C.

Synthesis

Naphtharazin can be prepared by condensation of 1,4-dimethoxybenzene

1,4-Dimethoxybenzene

1,4-Dimethoxybenzene is the para form of dimethoxybenzene, a volatile aromatic ether with a sweet floral odor. It occurs naturally in willow and zucchini . It appears to attract bees as it has a powerful response in their antenna.-Uses:Dimethoxybenzene is useful as an intermediate in synthesis...

 with 2,3-dichloromaleic anhydride followed by reductive dechlorination and reoxidation.

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