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 too 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.
December 31, 2022
pyran, chemistry, pyran, oxine, membered, heterocyclic, aromatic, ring, consisting, five, carbon, atoms, oxygen, atom, containing, double, bonds, molecular, formula, c5h6o, there, isomers, pyran, that, differ, location, double, bonds, pyran, saturated, carbon,. 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 Pyran 2H pyran 4H pyranNamesIUPAC name 2H Pyran 4H PyranOther names 2H Oxine 4H OxineIdentifiersCAS Number 289 66 7 2H Y289 65 6 4H Y3D model JSmol 2H Interactive image 4H Interactive imageChemSpider 161812 2H Y119912 4H YPubChem CID 186148 2H 136135 4H UNII CH5P2A5WTT YCompTox Dashboard EPA DTXSID80893659InChI 2H InChI 1S C5H6O c1 2 4 6 5 3 1 h1 4H 5H2Key MGADZUXDNSDTHW UHFFFAOYSA N 4H InChI 1S C5H6O c1 2 4 6 5 3 1 h2 5H 1H2Key MRUWJENAYHTDQG UHFFFAOYSA NSMILES 2H C1 CC CCO1 4H C1 CCC CO1PropertiesChemical formula C 5H 6OMolar mass 82 102 g mol 1Related compoundsRelated compounds DihydropyranTetrahydropyranExcept where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Infobox references 4H Pyran was first isolated and characterized in 1962 via pyrolysis of 2 acetoxy 3 4 dihydro 2H pyran 1 It was found too 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 See also EditFuran Furfural Pyrone ThiopyranReferences Edit Masamune S Castellucci N T 1962 g Pyran Journal of the American Chemical Society 84 12 2452 2453 doi 10 1021 ja00871a037 Retrieved from https en wikipedia org w index php title Pyran amp oldid 1126520565, wikipedia, wiki, book, books, library,
