Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
Chemical compound
In chemistry, pyran, or oxine, is a six-membered heterocyclic, non-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.
4H-Pyran was first isolated and characterized in 1962 via pyrolysis of 2-acetoxy-3,4-dihydro-2H-pyran.[1] It was found to be unstable, particularly in the presence of air. 4H-pyran easily disproportionates to the corresponding dihydropyran and the pyrylium ion, which is easily hydrolyzed in aqueous medium.
Although the pyrans themselves have little significance in chemistry, many of their derivatives are important biological molecules, such as the pyranoflavonoids.
The term pyran is also often applied to the saturated ring analog, which is more properly referred to as tetrahydropyran (oxane). In this context, the monosaccharides containing a six-membered ring system are known as pyranoses.
^Masamune, S.; Castellucci, N. T. (1962). "γ-Pyran". Journal of the American Chemical Society. 84 (12): 2452–2453. doi:10.1021/ja00871a037.
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...
heterocyclic compounds with the formula C5H8O: 3,4-Dihydro-2H-pyran 3,6-dihydro-2H-pyran In IUPAC names, "dihydro" refers to the two added hydrogen atoms...
chemicals with two hydrogen molecules 2H-pyran, a form of Pyran 2H-1-benzopyran, a form of Benzopyran 2H-pyran-2-one, a form of 2-Pyrone 2H, a harder grade...
4-benzopyrone) is a derivative of benzopyran with a substituted keto group on the pyran ring. It is an isomer of coumarin. Derivatives of chromone are collectively...
eliminated the pyran ring, identifying MupW as being involved in ring formation. The epoxide of PA-A at C10-11 is believed to be inserted after pyran formation...
temperatures due to brush fires. In particular, 3-methyl-2H-furo[2,3-c]pyran-2-one was found to trigger seed germination in plants whose reproduction...
"Crystal Structure and Magnetic Properties of Tris(2-hydroxymethyl-4-oxo-4H-pyran- 5-olato-κ2O5,O4)iron(III)". Journal of Coordination Chemistry. 60 (14):...
carbohydrates. Glucose is present in solid form as a monohydrate with a closed pyran ring (α-glucopyranose monohydrate, sometimes known less precisely by dextrose...
containing five carbon atoms and one oxygen atom. It is named by reference to pyran, which contains two double bonds, and may be produced from it by adding...
Piran or Pyran (Cornish: Peran; Latin: Piranus), died c. 480, was a 5th-century Cornish abbot and saint, possibly of Irish origin. He is the patron saint...
called furanoses and pyranoses, respectively—by analogy with furan and pyran, the simplest compounds with the same carbon-oxygen ring (although they...
molten cellulose produces volatile compounds including levoglucosan, furans, pyrans, light oxygenates, and gases via primary reactions. Within thick cellulose...
Cyclopentenone, or 2-cyclopentenone Methylfuran 2-Methylfuran 3-Methylfuran Pyran, or oxine This set index page lists chemical structure articles associated...
class of chemical compounds that have a core structure that consists of a pyran ring fused to a coumarin. As phytochemicals, pyranocoumarins are uncommon...
2-pyrone or pyran-2-one (2). Important representatives of this class are the coumarins. Likewise a 4-hydroxyl pyrylium compound is a γ-pyrone or pyran-4-one...
the ring. The name derives from its similarity to the oxygen heterocycle pyran, but the pyranose ring does not have double bonds. A pyranose in which the...
compound that results from the fusion of a benzene ring to a heterocyclic pyran ring. According to current IUPAC nomenclature, the name chromene used in...
(March 1977). "Chemoattractant properties of Corynebacterium parvum and pyran copolymer for human monocytes and neutrophils". Journal of the National...
monoterpenoid based compound. Aucubin, like all iridoids, has a cyclopentan-[C]-pyran skeleton. Iridoids can consist of ten, nine, or rarely eight carbons in...
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