Mesoxalic acid

Mesoxalic acid, also called oxomalonic acid or ketomalonic acid, is an organic compound with formula C₃H₂O₅ or HO−(C=O)₃−OH.

Mesoxalic acid^[1]

Names
Preferred IUPAC name Oxopropanedioic acid
Other names Ketomalonic acid Oxomalonic acid α-Ketomalonic acid 2-Oxopropanedioic acid
Identifiers
CAS Number	473-90-5 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:30842 Y
ChemSpider	9727 Y
DrugBank	DB03589 Y
ECHA InfoCard	100.006.796
KEGG	C00830 Y
PubChem CID	10132
UNII	62R514HE48 Y
CompTox Dashboard (EPA)	DTXSID3021649
InChI InChI=1S/C3H2O5/c4-1(2(5)6)3(7)8/h(H,5,6)(H,7,8) Y Key: XEEVLJKYYUVTRC-UHFFFAOYSA-N Y InChI=1/C3H2O5/c4-1(2(5)6)3(7)8/h(H,5,6)(H,7,8) Key: XEEVLJKYYUVTRC-UHFFFAOYAW
SMILES O=C(O)C(=O)C(=O)O
Properties
Chemical formula	C3H2O5
Molar mass	118.045 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Mesoxalic acid is both a dicarboxylic acid and a ketonic acid. It readily loses two protons to yield the divalent anion C₃O2−5, called mesoxalate, oxomalonate, or ketomalonate. These terms are also used for salts containing this anion, such as sodium mesoxalate, Na₂C₃O₅; and for esters containing the −C₃O₅− or −O−(C=O)₃−O− moiety, such as diethyl mesoxalate, (C₂H₅)₂C₃O₅. Mesoxalate is one of the oxocarbon anions, which (like carbonate CO2−3 and oxalate C₂O2−4) consist solely of carbon and oxygen.

Mesoxalic acid readily absorbs and reacts with water to form a product commonly called "mesoxalic acid monohydrate", more properly dihydroxymalonic acid, HO−(C=O)−C(OH)₂−(C=O)−OH.^[2] In product catalogs and other contexts, the terms "mesoxalic acid", "oxomalonic acid" and so on often refer to this "hydrated" compound. In particular, the product traded as "sodium mesoxalate monohydrate" is almost always sodium dihydroxymalonate.

Synthesis

Mesoxalic acid can be obtained synthetically by hydrolysis of alloxan with baryta water,^[2] by warming caffuric acid^[3] with lead acetate solution,^[2] or from glyceryl diacetate and concentrated nitric acid in ice-cold water. The product can be obtained also by oxidation of tartronic acid^[4] or glycerol.^[5] Since they are carried out in water, these procedures generally give the dihydroxy derivative.

It is also prepared by the oxidation of glycerol with the help of bismuth(III) nitrate.

See also

• Malonic acid

References

1. Merck Index (12th ed.). p. 5971.
2. Henry Enfield Roscoe (1888), A Treatise on Chemistry, volume 3, part2 Organic Chemistry, p. 161. D. Appleton and Co., New York
3. The chemical structure of caffuric acid was given in Allen, W. F. (1932). The preparation and pyrolytic molecular rearrangment [sic] of the 8-ethers of caffeine: And their conversion to 8-methyl and 8-ethylcaffeine. Ann Arbor, Mich.: Edwards Brothers.
4. Rosaria Ciriminna and Mario Pagliaro (2004), Oxidation of tartronic acid and dihydroxyacetone to sodium mesoxalate mediated by TEMPO. Tetrahedron Letters, volume 45, issue 34, pp. 6381–6383 doi:10.1016/j.tetlet.2004.07.021
5. Rosaria Ciriminna and Mario Pagliaro (2003), One-Pot Homogeneous and Heterogeneous Oxidation of Glycerol to Ketomalonic Acid Mediated by TEMPO. Advanced Synthesis & Catalysis, volume 345, issue 3, Pages 383–388. doi:10.1002/adsc.200390043