3-Oxopropanoic acid

3-Oxopropanoic acid (also malonic semialdehyde or formylacetic acid) is an organic chemical compound that carries both a carboxylic acid function and an aldehyde function.

3-Oxopropanoic acid

Names
IUPAC name 3-Oxopropanoic acid
Other names malonic semialdehyde, formylacetic acid, 3-oxopropanoate
Identifiers
CAS Number	926-61-4 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1741700
ChEBI	CHEBI:17960
ChemSpider	845
Gmelin Reference	164397
KEGG	C00222
PubChem CID	868
UNII	9K1T0U0R4C
CompTox Dashboard (EPA)	DTXSID90239064
InChI InChI=1S/C3H3O3/c4-2-1-3(5)6/h1H2,(H,5,6)/q-1 Key: HBHVBGOPNWLCDZ-UHFFFAOYSA-N
SMILES C([C-]=O)C(=O)O
Properties
Chemical formula	C3H4O3
Molar mass	88.062 g·mol−1
Density	1.258 g/cm3
Boiling point	237.3 °C (459.1 °F; 510.4 K)
Hazards
GHS labelling:[1]
Pictograms
Signal word	Warning
Flash point	111.6 °C[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Natural occurrence

In nature, 3-oxopropanoic acid occurs as a metabolic intermediate. It is formed, for example, by the reversible oxidation of 3-hydroxypropionyl-CoA with nicotinamide adenine dinucleotide (NAD).^[3]

A bacterial strain of the species Pseudomonas fluorescens is known to survive on propiolic acid as its sole carbon and energy source. 3-Oxopropanoic acid is an important metabolic intermediate: it is formed by hydration of acetylenic acid and is converted into acetyl-CoA by decarboxylation.^[4] It also occurs as a metabolic intermediate in a strain of Escherichia coli that can grow on uracil as its sole nitrogen source.^[5]

3-Oxopropanoic acid also occurs in atmospheric aerosols along with various other organic acids (especially oxalic acid). It has been detected as an aerosol component at various stations during a circumnavigation of the globe by ship.^[6] The compound has also been found in aerosol analyses in the Arctic,^[7] the North Pacific,^[8] India,^[9] and Tokyo.^[10]

Synthesis

3-Oxopropanoic acid is highly reactive. It is often generated in situ by reacting malic acid with concentrated sulfuric acid. This process releases formic acid, water, and carbon monoxide.^[11]

A readily storable precursor to the compound is ethyl 3-oxopropionate diethyl acetal. This can be prepared by condensation of ethyl acetate and ethyl formate, followed by acetalization with hydrogen chloride in absolute ethanol. The 3-oxopropanoic acid can also be obtained from it by hydrolysis with dilute sulfuric acid followed by neutralization.

Reactions

Reaction with a phenol yields coumarin. The enol form, which is initially formed during the preparation from malic acid and sulfuric acid, can condense with urea to form uracil.^[11]

Isocytosine was prepared analogously, using guanidine hydrochloride instead of urea.^[12]