Hydroxyquinone

Hydroxyquinone often refers to a hydroxybenzoquinone, any organic compound with formula C
₆H
₄O
₃ which can be viewed as a derivative of a benzoquinone through replacement of one hydrogen atom (H) by a hydroxyl group (-OH). When unqualified, the terms usually mean specifically the compound 2-hydroxy-1,4-benzoquinone, derived from 1,4-benzoquinone or para-benzoquinone (which often called just "quinone").

2-Hydroxy-
1,4-benzoquinone
(Hydroxyquinone)

More generally, the term may refer to any derivative of any quinone (such as 1,2-benzoquinone, 1,4-naphthoquinone or 9,10-anthraquinone), where any number n of hydrogens have been replaced by n hydroxyls. In this case the number n is indicated by a multiplier prefix (mono-, di-, tri-, etc.), and the parent quinone's name is used instead of just "quinone" — as in tetrahydroxy-1,4-benzoquinone.

Tetrahydroxy-
1,4-benzoquinone

5-Hydroxy-
1,4-naphthoquinone
(Juglone)

1,2-Dihydroxy-
9,10-anthraquinone
(Alizarin)

The hydroxyquinones (in the particular or the general sense) include many biologically and industrially important compounds, and are a building block of many medicinal drugs.

Hydroxyquinones with hydroxyls adjacent to the ketone groups often exhibit intramolecular hydrogen bonding, which affects their redox properties and their biochemical properties.[1]

The term "hydroxyquinone" should not be confused with hydroquinone, the common name of benzene-1,4-diol.