View source for 2-Pyrone

{{Chembox new
|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
|IUPACName=Pyran-2-one
|OtherNames=α-Pyrone<br>2-Pyranone<br>2''H''-Pyran-2-one 
|Section1= {{Chembox Identifiers
|  CASNo=504-31-4 
|  PubChem=68154
|  SMILES=C1=CC(=O)OC=C1
  }}
|Section2= {{Chembox Properties
|  Formula=C<sub>5</sub>H<sub>4</sub>O<sub>2</sub>
|  MolarMass=96.08
|  Appearance=
|  Density=1.197 g/mL
|  MeltingPt=
|  BoilingPt=102-103 °C at 20 mmHg
|  Solubility=
  }}
|Section3= {{Chembox Hazards
|  MainHazards=
|  FlashPt=
|  Autoignition=
  }}
}}
{{CMG}}
__NOTOC__


==Overview==

'''2-Pyrone''' ('''α-pyrone''' or '''pyran-2-one''') is an [[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>Woodard BT, Posner G H. "Recent Advances in Diels-Alder Cycloadditions Using 2-Pyrones." ''Advances in Cycloaddition''. 1999, 5, 47-83.</ref>. The '''Gogte Synthesis''' (1938) is a method for the alkylation of certain pyrones with acid chlorides.

2-Pyrone also forms the the core structure of a variety of natural organic compounds.  For example, the [[coumarin]]s are an important class of compounds which are benzo-fused derivatives of 2-pyrone.

<gallery>
Image:4-Pyranone.png|4-Pyrone
Image:Coumarin acsv.svg|Coumarin
</gallery>

==References==
<references/>

{{DEFAULTSORT:Pyrone, 2-}}
[[Category:Lactones]]


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