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'''Tetrahydropyran''' ('''THP''') is the [[organic compound]] consisting of a saturated six-membered ring 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 four hydrogens. In 2013, its preferred IUPAC name was established as '''oxane'''.<ref>{{cite web|url=http://bulletin.acscinf.org/PDFs/247nm44.pdf|title=New IUPAC Organic Nomenclature - Chemical Information BULLETIN}}</ref> The compound is a colourless volatile liquid. Derivatives of tetrahydropyran are, however, more common. 2-Tetrahydropyranyl (THP-) ethers derived from the reaction of alcohols and [[3,4-Dihydropyran|3,4-dihydropyran]] are commonly used as protecting groups in [[organic synthesis]].<ref name = Greene /> Furthermore, a tetrahydropyran ''ring system'', i.e., five carbon atoms and an oxygen, is the core of [[pyranose]] sugars, such as [[glucose]]. |
'''Tetrahydropyran''' ('''THP''') is the [[organic compound]] consisting of a saturated six-membered ring 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 four hydrogens. In 2013, its preferred IUPAC name was established as '''oxane'''.<ref>{{cite web|url=http://bulletin.acscinf.org/PDFs/247nm44.pdf|title=New IUPAC Organic Nomenclature - Chemical Information BULLETIN}}</ref> The compound is a colourless volatile liquid. Derivatives of tetrahydropyran are, however, more common. 2-Tetrahydropyranyl (THP-) ethers derived from the reaction of alcohols and [[3,4-Dihydropyran|3,4-dihydropyran]] are commonly used as protecting groups in [[organic synthesis]].<ref name = Greene /> Furthermore, a tetrahydropyran ''ring system'', i.e., five carbon atoms and an oxygen, is the core of [[pyranose]] sugars, such as [[glucose]]. |
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==Structure and preparation== |
==Structure and preparation== |
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:[[File:THPmeth.png|thumb|center|320 px|Protection of alcohol as THP ether followed by deprotection. Both steps require acid catalysts.]] |
:[[File:THPmeth.png|thumb|center|320 px|Protection of alcohol as THP ether followed by deprotection. Both steps require acid catalysts.]] |
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In a typical procedure, the alcohol is treated with [[3,4-Dihydropyran|3,4-dihydropyran]] and [[P-Toluenesulfonic acid|''p''-toluenesulfonic acid]] in [[dichloromethane]] at ambient temperature.<ref name = Greene>{{cite book|title = Greene's Protective Groups in Organic Synthesis|chapter = Protection for the Hydroxyl Group, Including 1,2‐ and 1,3‐Diols|pages = |
In a typical procedure, the alcohol is treated with [[3,4-Dihydropyran|3,4-dihydropyran]] and [[P-Toluenesulfonic acid|''p''-toluenesulfonic acid]] in [[dichloromethane]] at ambient temperature.<ref name = Greene>{{cite book|title = Greene's Protective Groups in Organic Synthesis|chapter = Protection for the Hydroxyl Group, Including 1,2‐ and 1,3‐Diols|pages = 16–366|edition = 4th|last1 = Wuts|first1 = Peter G. M.|last2 = Greene|first2 = Theodora W.|doi = 10.1002/9780470053485.ch2|year = 2006|isbn = 9780470053485}}</ref> |
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[[File:THPProtection.png|center|thumb|610x610px|THP protection used in the [[total synthesis]] of solandelactone E<ref>{{Cite journal|last1=Robinson|first1=Anna|last2=Aggarwal|first2=Varinder K.|date=2010|title=Asymmetric Total Synthesis of Solandelactone E: Stereocontrolled Synthesis of the 2-ene-1,4-diol Core through a Lithiation–Borylation–Allylation Sequence|journal=[[Angewandte Chemie International Edition]]|volume=49|issue=37|pages=6673–6675|doi=10.1002/anie.201003236}}</ref>]] |
[[File:THPProtection.png|center|thumb|610x610px|THP protection used in the [[total synthesis]] of solandelactone E<ref>{{Cite journal|last1=Robinson|first1=Anna|last2=Aggarwal|first2=Varinder K.|date=2010|title=Asymmetric Total Synthesis of Solandelactone E: Stereocontrolled Synthesis of the 2-ene-1,4-diol Core through a Lithiation–Borylation–Allylation Sequence|journal=[[Angewandte Chemie International Edition]]|volume=49|issue=37|pages=6673–6675|doi=10.1002/anie.201003236}}</ref>]] |
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Revision as of 10:34, 31 March 2019
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Names | |||
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IUPAC name
Oxane
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Other names
Tetrahydropyran,
Oxacyclohexane, 1,5-epoxypentane | |||
Identifiers | |||
3D model (JSmol)
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ChEBI | |||
ChemSpider | |||
DrugBank | |||
ECHA InfoCard | 100.005.048 | ||
KEGG | |||
PubChem CID
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UNII | |||
CompTox Dashboard (EPA)
|
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Properties | |||
C5H10O | |||
Molar mass | 86.134 g·mol−1 | ||
Density | 0.880 g/cm3 | ||
Melting point | −45 °C (−49 °F; 228 K) | ||
Boiling point | 88 °C (190 °F; 361 K) | ||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards
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Flammable, Causes skin irritation | ||
NFPA 704 (fire diamond) | |||
Flash point | −15.6 °C (3.9 °F; 257.5 K) | ||
Lethal dose or concentration (LD, LC): | |||
LDLo (lowest published)
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3000 mg/kg (oral, rat) | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
Tetrahydropyran (THP) is the organic compound consisting of a saturated six-membered ring 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 four hydrogens. In 2013, its preferred IUPAC name was established as oxane.[1] The compound is a colourless volatile liquid. Derivatives of tetrahydropyran are, however, more common. 2-Tetrahydropyranyl (THP-) ethers derived from the reaction of alcohols and 3,4-dihydropyran are commonly used as protecting groups in organic synthesis.[2] Furthermore, a tetrahydropyran ring system, i.e., five carbon atoms and an oxygen, is the core of pyranose sugars, such as glucose.
Structure and preparation
In gas phase, the THP exists in its lowest energy Cs symmetry chair conformation.[3]
One classic procedure for the organic synthesis of tetrahydropyran is by hydrogenation of the 3,4-isomer of dihydropyran with Raney nickel.[4]
Tetrahydropyranyl derivatives
Although tetrahydropyran is an obscure compound, tetrahydropyranyl ethers are commonly use in organic synthesis. Specifically, the 2-tetrahydropyranyl (THP) group is a common protecting group for alcohols.[5][6] Alcohols react with 3,4-dihydropyran to give 2-tetrahydropyranyl ethers. These ethers are resilient to a variety of reactions. The alcohol can later be restored by acid-catalyzed hydrolysis. This hydrolysis reforms the parent alcohol as well as 5-hydroxypentanal. THP ethers derived from chiral alcohols form diastereomers. Another undesirable feature is that the ethers display complex NMR spectra, which interfere with analysis.[2]
In a typical procedure, the alcohol is treated with 3,4-dihydropyran and p-toluenesulfonic acid in dichloromethane at ambient temperature.[2]
Alternatively the THP ether is generated under the conditions akin to those for the Mitsunobu reaction. Thus the alcohol is treated with 2-hydroxytetrahydropyranyl, triphenylphosphine, diethyl azodicarboxylate (DEAD) in tetrahydrofuran (THF).
Commonly THP ethers are deprotected using Acetic acid in THF/water solution, p-toluenesulfonic acid in water, or Pyridinium p-toluenesulfonate (PPTS) in ethanol
See also
- Pyran
- Dioxane and Trioxane, which have two and three oxygen atoms as part of their six-membered rings respectively
References
- ^ "New IUPAC Organic Nomenclature - Chemical Information BULLETIN" (PDF).
- ^ a b c Wuts, Peter G. M.; Greene, Theodora W. (2006). "Protection for the Hydroxyl Group, Including 1,2‐ and 1,3‐Diols". Greene's Protective Groups in Organic Synthesis (4th ed.). pp. 16–366. doi:10.1002/9780470053485.ch2. ISBN 9780470053485.
- ^ Builth-Williams, J. D.; Bellm, S. M.; Chiari, L.; Thorn, P. A.; Jones, D. B.; Chaluvadi, H.; Madison, D. H.; Ning, C. G.; Lohmann, B. (2013). "A dynamical (e,2e) investigation of the structurally related cyclic ethers tetrahydrofuran, tetrahydropyran, and 1,4-dioxane" (PDF). Journal of Chemical Physics. 139 (3): 034306. doi:10.1063/1.4813237.
- ^ Andrus, D. W.; Johnson, John R. (1943). "Tetrahydropyran". Organic Syntheses. 23: 90. doi:10.15227/orgsyn.023.0090; Collected Volumes, vol. 3, p. 794.
- ^ Earl, R. A.; Townsend, L. B. (1981). "Methyl 4-Hydroxy-2-butynoate". Organic Syntheses. 60: 81. doi:10.15227/orgsyn.060.0081; Collected Volumes, vol. 7, p. 334.
- ^ Kluge, Arthur F. (1986). "Diethyl [(2-Tetrahydropyranyloxy)methyl]phosphonate". Organic Syntheses. 64: 80. doi:10.15227/orgsyn.064.0080; Collected Volumes, vol. 7, p. 160.
- ^ Robinson, Anna; Aggarwal, Varinder K. (2010). "Asymmetric Total Synthesis of Solandelactone E: Stereocontrolled Synthesis of the 2-ene-1,4-diol Core through a Lithiation–Borylation–Allylation Sequence". Angewandte Chemie International Edition. 49 (37): 6673–6675. doi:10.1002/anie.201003236.