Pyran
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2008-03-16T20:04:01Z
McM.bot
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robot Adding: [[pl:Piran (związek chemiczny)]]
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|ImageFileL1=2H-Pyran.png
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|ImageFileR1=Pyran3d.png
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|ImageFileL2=4H-Pyran.png
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|ImageFileR2=4HPyran3d.png
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|IUPACName=Pyran
|OtherNames=2H-Pyran, 4H-Pyran
|Section1= {{Chembox Identifiers
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|Section2= {{Chembox Properties
| Formula=C<sub>5</sub>H<sub>6</sub>O
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|Section3= {{Chembox Hazards
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| Section8 = {{Chembox Related
| OtherCpds = [[Tetrahydropyran]]
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In [[chemistry]], a '''pyran''' is a six membered [[heterocyclic]] ring consisting of five [[carbon]] atoms and one [[oxygen]] atom and containing two [[double bond]]s. The [[molecular formula]] is C<sub>5</sub>H<sub>6</sub>O. There are two [[isomer]]s of pyran that differ by the location of the double bonds. In 2''H''-pyran, the saturated carbon is at position 2, whereas in 4''H''-pyran, the saturated carbon is at position 4.
Although the pyrans themselves have little significance in chemistry, a variety of their derivatives are important biological molecules. 4H-pyrane easily disproportionates to the corresponding [[dihydropyrane|dihydropyrane]] and the [[pyrylium]] ion which is easily hydrolyzed in aqueous medium.
The term pyran is also often applied to the saturated ring analog which is more properly referred to as [[tetrahydropyran]]. In this context, the [[monosaccharide]]s containing a six-membered ring system are known as [[pyranose]]s. Hence, the six-membered ring form of [[glucose]] is known as D-glucopyranose.
== See also ==
* [[Furan]]
[[Category:Oxygen heterocycles]]
[[de:Pyrane]]
[[fr:Pyrane]]
[[it:Pirano (chimica)]]
[[nl:Pyraan]]
[[ja:ピラン (化学)]]
[[pl:Piran (związek chemiczny)]]