1,2-Benzoquinone

It is a red volatile solid that is soluble in water and diethyl ether.

It is rarely encountered because of its instability, but it is of fundamental interest as the parent compound of many derivatives which are known.

X-ray crystallography shows that the double bonds are localized, with alternatingly long and short C-C distances within the ring.

[6] A strain of the bacterium Pseudomonas mendocina metabolises benzoic acid, yielding 1,2-benzoquinone via catechol.

Finally, the enzyme cofactors tryptophan tryptophylquinone (TTQ), cysteine tryptophylquinone (CTQ), lysine tyrosylquinone (LTQ) and pyrroloquinoline quinone (PQQ) contain the ortho-quinone moiety in their chemical structure.

The oxidation of lysyl side chains is effected in nature by the action of an orthoquinone called lysyl tyrosylquinone.