Acetolactone

In organic chemistry, α‑lactone refers to a functional group, the smallest possible lactone. It is a family of unstable, three-membered heterocycles, containing an epoxide ring fused with a carbonyl group.

Acetolactone

Structural formula Ball-and-stick model
Names
IUPAC name Oxiran-2-one[1]
Preferred IUPAC name Oxiranone
Identifiers
CAS Number	42879-41-4
3D model (JSmol)	Interactive image
ChemSpider	393042 Y
PubChem CID	445391
CompTox Dashboard (EPA)	DTXSID30332189
InChI InChI=1S/C2H2O2/c3-2-1-4-2/h1H2 Y Key: HZSIFDFXFAXICF-UHFFFAOYSA-N Y InChI=1/C2H2O2/c3-2-1-4-2/h1H2 Key: HZSIFDFXFAXICF-UHFFFAOYAQ
SMILES O=C1OC1
Properties
Chemical formula	C2H2O2
Molar mass	58.036 g·mol−1
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

The parent, acetolactone (α-acetolactone), is an organic compound with formula C
₂H
₂O
₂, and has not been isolated in bulk. The compound was first described in 1997 as a transient species in mass spectrometry experiments.^[2]

Generally, α‑lactones are produced by the cryogenic, photochemical decarboxylation of peroxymalonic anhydrides. Even at 77 K, the products rapidly polymerize or decarbonylate to ketones or aldehydes.^[3]

An exception is bis(trifluoromethyl)acetolactone ((CF
₃)
₂C
₂O
₂), stabilized by its two trifluoromethyl groups. That compound has a half-life of 8 hours at 25 °C.^[4]

Α-Thiolactones can be produced via oxygen transfer from a nitrone to a thioketene.^[5]

See also

• α-Propiolactone
• Oxalic anhydride