2-Furanone is a heterocyclic organic compound. It is also known as γ-crotonolactone (GCL), as it is formally the lactone derived from γ-hydroxyisocrotonic acid. The chemical is colloquially called "butenolide", and is the parent structure for the butenolide class of compounds. It is a colourless liquid.

Quick Facts Names, Identifiers ...

2-Furanone

Names
Preferred IUPAC name Furan-2(5H)-one
Other names Furan-2-one, γ-crotonolactone, butenolide, 5H-furan-2-one
Identifiers
CAS Number	497-23-4 Y
3D model (JSmol)	Interactive image
Beilstein Reference	383585
ChEBI	CHEBI:38118 Y
ChEMBL	ChEMBL166223 Y
ChemSpider	9917 Y
ECHA InfoCard	100.007.128
EC Number	207-839-3
Gmelin Reference	773828
KEGG	C17601 Y
MeSH	butenolide
PubChem CID	10341
UNII	8KXK25H388 Y
CompTox Dashboard (EPA)	DTXSID7075422
InChI InChI=1S/C4H4O2/c5-4-2-1-3-6-4/h1-2H,3H2 Y Key: VIHAEDVKXSOUAT-UHFFFAOYSA-N Y InChI=1/C4H4O2/c5-4-2-1-3-6-4/h1-2H,3H2 Key: VIHAEDVKXSOUAT-UHFFFAOYAD
SMILES O=C\1OC/C=C/1
Properties
Chemical formula	C4H4O2
Molar mass	84.07336
Density	1.185 g/cm3, liquid
Melting point	4 to 5 °C (39 to 41 °F; 277 to 278 K)[1]
Boiling point	86 to 87 °C (187 to 189 °F; 359 to 360 K) 12 mm Hg[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

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2-Furanone is prepared by oxidation of furfural:^[2]

It exists in equilibrium with the tautomer 2-hydroxyfuran, which serves as an intermediate in the interconversion between the β- and α-furanones.^{[further explanation needed]} The β form is the more stable. The interconversion is catalyzed by base.

2-Furanones can be converted to furans by a two-step process of reduction followed by dehydration.

• Category:Furanones, various substituted structural analogs
• Pyrone, which has one more carbon atom in the ring