2-Pyrone

2-Pyrone (α-pyrone or pyran-2-one) is an unsaturated cyclic chemical compound with the molecular formula C₅H₄O₂. It is isomeric with 4-pyrone.

2-Pyrone^[1]

Names
Preferred IUPAC name 2H-Pyran-2-one
Other names α-Pyrone 2-Pyranone Pyran-2-one
Identifiers
CAS Number	504-31-4 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:37965 Y
ChemSpider	61462 Y
ECHA InfoCard	100.007.264
PubChem CID	68154
UNII	8WW45I202V Y
CompTox Dashboard (EPA)	DTXSID50198441
InChI InChI=1S/C5H4O2/c6-5-3-1-2-4-7-5/h1-4H Y Key: ZPSJGADGUYYRKE-UHFFFAOYSA-N Y InChI=1/C5H4O2/c6-5-3-1-2-4-7-5/h1-4H Key: ZPSJGADGUYYRKE-UHFFFAOYAI
SMILES O=C\1O\C=C/C=C/1
Properties
Chemical formula	C5H4O2
Molar mass	96.085 g·mol−1
Density	1.197 g/mL
Boiling point	102 to 103 °C (216 to 217 °F; 375 to 376 K) at 20 mmHg
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

2-Pyrone is used in organic synthesis as a building block for more complex chemical structures because it may participate in a variety of cycloaddition reactions to form bicyclic lactones. For example, it readily undergoes Diels-Alder reactions with alkynes producing, upon loss of carbon dioxide, substituted benzenes.^[2] The Gogte Synthesis (1938) is a method for the alkylation of certain pyrones with acid chlorides.^{[citation needed]}

The parent 2-pyrone can be produced from decarboxylation of coumalic acid.^[3]

Derivatives

The most common natural products containing a 2-pyrone are the bufanolides and kavalactones. Oxovitisin A, a pyranoanthocyanin found in wine, also contains a 2-pyrone element.

6-Amyl-α-pyrone (6PP) is a derivative of 2-pyrone, found in animal foods and heated beef.^[4] Due to its good organoleptic properties^{[citation needed]} with coconut aroma, it is used as flavor enhancer in the food industry. Biologically, it is produced by Trichoderma species via solid state fermentation.^[5]

Derivatives of 2-pyrone play a role as signalling molecules in bacterial communication, similar to quorum sensing. Cells with LuxR-type receptors, but lacking its homolog LuxI (and thus unable to produce N-acylhomoserine lactone QS signaling molecules) are known as LuxR "solos", to which pyrones bind as ligands facilitating cell-cell communication.^[6]

See also

• Pyrone

References

1. 2H-Pyran-2-one at Sigma-Aldrich
2. Woodard BT, Posner G H (1999). "Recent Advances in Diels-Alder Cycloadditions Using 2-Pyrones". Advances in Cycloaddition. 5: 47–83. doi:10.1016/S1052-2077(99)80004-3.
3. Fieser, L. F.; Fieser, M. (1957). Lehrbuch der organischen Chemie [Textbook of Organic Chemistry] (in German) (3rd ed.). Verlag Chemie. p. 943.
4. CID 33960 from PubChem
5. Ramos, Aline de Souza; Fiaux, Sorele Batista; Leite, Selma Gomes Ferreira (2008). "Production of 6-pentyl-α-pyrone by trichoderma harzianum in solid-state fermentation". Brazilian Journal of Microbiology. 39 (4): 712–717. doi:10.1590/S1517-83822008000400022. PMC 3768464. PMID 24031295.
6. Brachmann, Alexander; Brameyer, S.; Kresovic, D.; Hitkova, I.; Kopp, Y.; Manske, C.; Schubert, K.; Bode, H. B.; Heermann, R. (14 July 2013). "Pyrones as bacterial signaling molecules". Nature Chemical Biology. 9 (9). Nature Publishing Group: 573–578. doi:10.1038/nchembio.1295. PMID 23851573.