Any quinone in which the carbons of the two carbonyl groups in the quinone system are joined to each other by a single bond.
| Member | Definition | Role |
|---|
| 1,5(10)-estradiene-3,4,17-trione | An o-quinone resulting from the formal oxidation of the dihydroxyphenyl moiety of 4-hydroxyestrone. | estra-1,5(10)-diene-3,4,17-trione |
| acenaphthenequinone | An orthoquinone that is the 1,2-dioxo derivative of acenaphthene. | acenaphthoquinone |
| aminochrome 1 | A member of the class of indoledione that is 2,3,5,6-tetrahydro-1H-indole carrying oxo groups at positions 5 and 6; major microspecies at pH 7.3. It is an endogenous compound formed during dopamine oxidation and can induce neurotoxicity under certain aberrant conditions and induce Parkinson-like syndrome. | dopaminechrome (keto form) |
| benzo(a)pyrene-7,8-dione | An o-quinone resulting from the formal oxidation of both of the hydroxy groups of benzo[a]pyrene-cis-7,8-dihydrodiol. Benzo[a]pyrene-7,8-dione is a metabolite of the widespread carcinogen benzo[a]pyrene. | benzo[a]pyrene-7,8-dione |
| beta-lapachone | A benzochromenone that is 3,4-dihydro-2H-benzo[h]chromene-5,6-dione substituted by geminal methyl groups at position 2. Isolated from Tabebuia avellanedae, it exhibits antineoplastic and anti-inflammatory activities. | beta-lapachone |
| cysteine tryptophylquinone | An L-tryptophan derivative that is L-tryptophan-6,7-dione in which a cysteine unit is attached at position 4 via its side-chain thiol group. | cysteine tryptophylquinone |
| dopachrome | | dopachrome |
| estra-1(10),4-diene-2,3,17-trione | An o-quinone resulting from the formal oxidation of the dihydroxyphenyl moiety of 2-hydroxyestrone. | estra-1(10),4-diene-2,3,17-trione |
| phanquinone | An orthoquinone that is the 5,6-diketo derivative of 4,7-phenanthroline. | phanquone |
| pqq cofactor | A pyrroloquinoline having oxo groups at the 4- and 5-positions and carboxy groups at the 2-, 7- and 9-positions. | pyrroloquinoline quinone |