出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/03/15 09:40 UTC 版)
In chemistry, a pyran is a six-membered heterocyclic, not aromatic, ring consisting of five carbon atoms and one oxygen atom and containing two double bonds. The molecular formula is C5H6O. There are two isomers of pyran that differ by the location of the double bonds. In 2H-pyran, the saturated carbon is at position 2, whereas, in 4H-pyran, the saturated carbon is at position 4.