# 2-Pyrone

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> Source: https://en.wikipedia.org/wiki/2-Pyrone
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{{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](/source/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
| Density =1.197 g/mL
| BoilingPtC = 102 to 103
| BoilingPt_notes = at 20 mmHg
}}
}}

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

2-Pyrone is used in [organic synthesis](/source/organic_synthesis) as a building block for more complex chemical structures because it may participate in a variety of [cycloaddition reaction](/source/cycloaddition_reaction)s to form bicyclic [lactone](/source/lactone)s.  For example, it readily undergoes [Diels-Alder reaction](/source/Diels-Alder_reaction)s with [alkyne](/source/alkyne)s producing, upon loss of [carbon dioxide](/source/carbon_dioxide), substituted [benzene](/source/benzene)s.<ref>{{cite journal | author = Woodard BT, [Posner G H](/source/Gary_H._Posner) | 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](/source/decarboxylation) of [coumalic acid](/source/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](/source/bufanolide)s and [kavalactone](/source/kavalactone)s. [Oxovitisin A](/source/Oxovitisin_A), a pyranoanthocyanin found in wine, also contains a 2-pyrone element.

[6-Amyl-α-pyrone](/source/6-Amyl-%CE%B1-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](/source/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](/source/quorum_sensing). Cells with LuxR-type receptors, but lacking its homolog LuxI (and thus unable to produce [''N''-acylhomoserine lactone](/source/N-Acyl_Homoserine_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](/source/Nature_Chemical_Biology) |volume = 9 |issue = 9 |pages = 573–578 | publisher=[Nature Publishing Group](/source/Nature_Publishing_Group) |date=14 July 2013 |doi=10.1038/nchembio.1295 |pmid = 23851573}}</ref>

==See also==
* [Pyrone](/source/Pyrone)

== References ==
<references/>

{{DEFAULTSORT:Pyrone, 2-}}
Category:2-Pyrones

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Adapted from the Wikipedia article [2-Pyrone](https://en.wikipedia.org/wiki/2-Pyrone) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/2-Pyrone?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.