In
chemistry, a 'pyran' is a six membered
heterocyclic ring consisting of five
carbon atoms and one
oxygen atom and containing two
double bonds. The
molecular formula is C
5H
6O. There are two
isomers 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.
The term pyran is also often applied to the saturated ring analog which is more properly referred to as
tetrahydropyran. In this context, the
monosaccharides containing a six-membered ring system are known as
pyranoses. Hence, the six-membered ring form of
glucose is known as D-glucopyranose.
See also
★
Furan