Dioxosuccinic acid or dioxobutanedioic acid is an organic compound with formula C4H2O6 or HO−(C=O)4−OH.
Removal of two protons from the molecule would yield the dioxosuccinate anion, 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)<sub>4</sub>−O−] moiety.
Removal of a single proton would result in the monovalent anion hydrogendioxosuccinate, or HO−(C=O)4−O−.
Dioxosuccinic acid is one of the acids occurring naturally in wine, from the oxidation of tartaric acid via dihydroxyfumaric acid.[1]
The acid combines with two molecules of water to produce dihydroxytartaric acid, the ketone hydrate form, C4H6O8 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.[2]