View source for 2-Pyrone

{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 477215588
| Reference =<ref>[http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/463159 2H-Pyran-2-one] at [[Sigma-Aldrich]]</ref>
| ImageFile =2-Pyranone.png
| ImageSize =100px
| PIN =2''H''-Pyran-2-one
| OtherNames =α-Pyrone<br>2-Pyranone<br>Pyran-2-one 
|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 61462
| InChI = 1/C5H4O2/c6-5-3-1-2-4-7-5/h1-4H
| InChIKey = ZPSJGADGUYYRKE-UHFFFAOYAI
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C5H4O2/c6-5-3-1-2-4-7-5/h1-4H
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = ZPSJGADGUYYRKE-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo =504-31-4 
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 8WW45I202V
| PubChem =68154
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 37965
| SMILES = O=C\1O\C=C/C=C/1
}}
|Section2={{Chembox Properties
| C=5|H=4|O=2
| Appearance =
| Density =1.197 g/mL
| MeltingPt =
| BoilingPtC = 102 to 103
| BoilingPt_notes = at 20 mmHg
| Solubility =
  }}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt = 
 }}
}}

'''2-Pyrone''' ('''α-pyrone''' or '''pyran-2-one''') is an [[Saturated and unsaturated compounds|unsaturated]] cyclic chemical compound with the [[molecule|molecular]] formula C<sub>5</sub>H<sub>4</sub>O<sub>2</sub>. It is [[isomer]]ic with [[4-pyrone]].

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 reaction]]s to form bicyclic [[lactone]]s.  For example, it readily undergoes [[Diels-Alder reaction]]s with [[alkyne]]s producing, upon loss of [[carbon dioxide]], substituted [[benzene]]s.<ref>{{cite journal | author = Woodard BT, [[Gary H. Posner|Posner G H]] | title = Recent Advances in Diels-Alder Cycloadditions Using 2-Pyrones | journal = Advances in Cycloaddition | year = 1999 | volume = 5 | pages = 47–83| doi = 10.1016/S1052-2077(99)80004-3 }}</ref>  The Gogte Synthesis (1938) is a method for the alkylation of certain pyrones with acid chlorides.{{Citation needed|date=March 2008}}

The parent 2-pyrone can be produced from [[decarboxylation]] of [[coumalic acid]].<ref>{{cite book|first1=L.&nbsp;F.|last1=Fieser|author-link1=Louis Fieser|first2=M.|last2=Fieser|author-link2=Mary Peters Fieser|title=Lehrbuch der organischen Chemie|lang=de|trans-title=Textbook of Organic Chemistry|edition=3rd|publisher=Verlag Chemie|year=1957|page=943}}</ref>

==Derivatives==
The most common natural products containing a 2-pyrone are the [[bufanolide]]s and [[kavalactone]]s. [[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.<ref>{{PubChem|33960}}</ref> Due to its good organoleptic properties{{citation needed|date=July 2020}} with coconut aroma, it is used as flavor enhancer in the food industry. Biologically, it is produced by ''[[Trichoderma]]'' species via solid state fermentation.<ref>{{cite journal | doi = 10.1590/S1517-83822008000400022| pmid = 24031295| title = Production of 6-pentyl-α-pyrone by trichoderma harzianum in solid-state fermentation| journal = Brazilian Journal of Microbiology| volume = 39| issue = 4| pages = 712–717| year = 2008| last1 = Ramos| first1 = Aline de Souza| last2 = Fiaux| first2 = Sorele Batista| last3 = Leite| first3 = Selma Gomes Ferreira| pmc=3768464}}</ref>

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-Acyl Homoserine Lactone|''N''-acylhomoserine lactone]] QS signaling molecules) are known as LuxR "solos", to which pyrones bind as ligands facilitating cell-cell communication.<ref>{{cite journal
|last = Brachmann |first = Alexander |author2=Brameyer, S. |author3=Kresovic, D. |author4=Hitkova, I. |author5=Kopp, Y. |author6=Manske, C. |author7=Schubert, K. |author8=Bode, H. B. |author9=Heermann, R. |title = Pyrones as bacterial signaling molecules |journal=[[Nature Chemical Biology]] |volume = 9 |issue = 9 |pages = 573–578 | publisher=[[Nature Publishing Group]] |date=14 July 2013 |doi=10.1038/nchembio.1295 |pmid = 23851573 }}</ref>

==See also==
* [[Pyrone]]

== References ==
<references/>

{{DEFAULTSORT:Pyrone, 2-}}
[[Category:2-Pyrones| ]]