Dioxosuccinic acid
# Dioxosuccinic acid

Dioxosuccinic acid or dioxobutanedioic acid is an organic compound with formula $C_4H_2O_6$ or $HO−(C=O)_4−OH.$

Removal of two protons from the molecule would yield the dioxosuccinate anion, C $_4O^{2−}$ $_6$ or $^−O−(C=O)_4−O^−.$ This is one of the oxocarbon anions, which consist solely of carbon and oxygen. The name is also used for salts containing that anion, and for esters with the $[−O−(C=O)_4−O−]$ moiety.

Removal of a single proton would result in the monovalent anion hydrogendioxosuccinate, C $_4HO^−$ $_6$ or $HO−(C=O)_4−O^−.$

## Occurrence

Dioxosuccinic acid is one of the acids occurring naturally in wine, from the oxidation of tartaric acid via dihydroxyfumaric acid.

## Reactions

The acid combines with two molecules of water to produce dihydroxytartaric acid, the ketone hydrate form, $C_4H_6O_8$ or $HO−(C=O)−(C(OH)_2)_2−(C=O)−OH.$ Indeed, the product traded under the name "dioxosuccinic acid hydrate" appears to be that substance.

Dihydroxytartaric acid behaves like dioxosuccinic acid in some reactions; for example, it reacts with ethanol in the presence of hydrogen chloride to yield the ester diethyl dioxosuccinate, upon $isolation.^{:p.187}$

