Pinene
{{Short description|Oily organic chemical found in plants}}
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 446720672
| Name = Pinene
| ImageFile = Alpha-pinen.svg
| ImageSize = 150px
| ImageName = Pinene
| IUPACName = (1S,5S)-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene
(1S,5S)-6,6-dimethyl-2-methylenebicyclo[3.1.1]heptane
| OtherNames =
|Section1={{Chembox Identifiers
| SMILES = CC1=CCC2CC1C2(C)C
| index_label = (mixture)
| index2_label = (1R-α)
| index3_label = (1S-α)
| index4_label = (1R-β)
| index5_label = (1S-β)
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 1330-16-1
| CASNo2_Ref = {{cascite|correct|CAS}}
| CASNo2 = 7785-70-8
| CASNo3_Ref = {{cascite|correct|CAS}}
| CASNo3 = 7785-26-4
| CASNo4_Ref = {{cascite|correct|CAS}}
| CASNo4 = 19902-08-0
| CASNo5_Ref = {{cascite|correct|CAS}}
| CASNo5 = 18172-67-3
| ChEBI = 17187
| ChEBI2 = 28261
| ChEBI3 = 28660
| ChEBI5 = 50025
| ChemSpiderID2 = 74205
| ChemSpiderID3 = 389795
| ChemSpiderID4 = 8466294
| ChemSpiderID5 = 14198
| EC_number2 = 232-087-8
| PubChem2 = 82227
| PubChem3 = 15837102
| PubChem4 = 10290825
| PubChem5 = 440967
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 996299PUKB
| UNII2_Ref = {{fdacite|correct|FDA}}
| UNII2 = H6CM4TWH1W
| UNII3_Ref = {{fdacite|correct|FDA}}
| UNII3 = TZR3GM95PR
| UNII4_Ref = {{fdacite|correct|FDA}}
| UNII4 = IGO73S04D5
| UNII5_Ref = {{fdacite|correct|FDA}}
| UNII5 = AFN153A7SU
| RTECS =
}}
|Section2={{Chembox Properties
| Formula = C10H16
| MolarMass = 136.24 g/mol
| Appearance = Liquid
| Density = 0.86 g·cm−3 (alpha, 15 °C){{GESTIS|ZVG=491170|CAS=80-56-8|Name=alpha-Pinen|Date=07-January-2016}}{{GESTIS|ZVG=492888|Name=beta-Pinen|Date=07-January-2016}}
| Solubility = Practically insoluble in water
| MeltingPtC = −62 to −55
| BoilingPtC = 155 to 156
}}
}}
Pinene is a collection of unsaturated bicyclic monoterpenes. Two geometric isomers of pinene are found in nature, α-pinene and β-pinene. Both are chiral. As the name suggests, pinenes are found in pines. Specifically, pinene is the major component of the liquid extracts of conifers.{{Ullmann |doi=10.1002/14356007.a27_267|title=Turpentines |year=2000 |last1=Gscheidmeier |first1=Manfred |last2=Fleig |first2=Helmut |isbn=3527306730 }} Pinenes are also found in many non-coniferous plants such as camphorweed (Heterotheca){{Cite journal|vauthors=Lincoln DE, Lawrence BM|date=1984|title=The Volatile Constituents of Camphorweed, Heterotheca subaxillaris|journal=Phytochemistry|volume=23|issue=4|pages=933–934|doi=10.1016/S0031-9422(00)85073-6|bibcode=1984PChem..23..933L }} and big sagebrush (Artemisia tridentata).
Isomers
Biosynthesis
α-Pinene and β-pinene are both produced from geranyl pyrophosphate, via cyclisation of linaloyl pyrophosphate followed by loss of a proton from the carbocation equivalent. Researchers at the Georgia Institute of Technology and the Joint BioEnergy Institute have been able to synthetically produce pinene with a bacterium.{{Cite journal|vauthors=Sarria S, Wong B, Martín HG, Keasling JD, Peralta-Yahya P|date=2014|title=Microbial Synthesis of Pinene|journal=ACS Synthetic Biology|volume=3|issue=7|pages=466–475|doi=10.1021/sb4001382|pmid=24679043|doi-access=free}}{{open access}}
Plants
Alpha-pinene is the most widely encountered terpenoid in nature{{Cite book|url=https://www.taylorfrancis.com/books/e/9780429155666|title=Handbook of Essential Oils: Science, Technology, and Applications|vauthors=Noma Y, Asakawa Y|publisher=CRC Press|year=2010|isbn=9780429155666|veditors=Baser KH, Buchbauer G|edition=2nd|location=Boca Raton, FL|pages=585–736|chapter=Biotransformation of Monoterpenoids by Microorganisms, Insects, and Mammals|doi=10.1201/b19393 }} and is highly repellent to insects.{{cite journal |vauthors=Nerio LS, Olivero-Verbel J, Stashenko E |title=Repellent activity of essential oils: a review |journal=Bioresour Technol |volume=101 |issue=1 |pages=372–378 |year=2010 |doi=10.1016/j.biortech.2009.07.048 |pmid=19729299|bibcode=2010BiTec.101..372N }}
Alpha-pinene appears in conifers and numerous other plants. Pinene is a major component of the essential oils of Sideritis spp. (ironwort){{Cite journal|vauthors=Köse EO, Deniz İG, Sarıkürkçü C, Aktaş Ö, Yavuz M|date=2010|title=Chemical composition, antimicrobial and antioxidant activities of the essential oils of Sideritis erythrantha Boiss. and Heldr. (var. erythrantha and var. cedretorum P.H. Davis) endemic in Turkey|journal=Food and Chemical Toxicology|volume=48|issue=10|pages=2960–2965|doi=10.1016/j.fct.2010.07.033|pmid=20670669}} and
Salvia spp. (sage).{{Cite journal|display-authors=6|vauthors=Özek G, Demirci F, Özek T, Tabanca N, Wedge DE, Khan SI, Başer KH, Duran A, Hamzaoglu E|date=2010|title=Gas chromatographic-mass spectrometric analysis of volatiles obtained by four different techniques from Salvia rosifolia Sm., and evaluation for biological activity|journal=Journal of Chromatography A|volume=1217|issue=5|pages=741–748|doi=10.1016/j.chroma.2009.11.086|pmid=20015509}} Cannabis also contains alpha-pinene{{cite journal|vauthors=Russo EB|date=2011|title=Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects|journal=British Journal of Pharmacology|volume=163|issue=7|pages=1344–1364|doi=10.1111/j.1476-5381.2011.01238.x|pmc=3165946|pmid=21749363}} and beta-pinene.{{Cite journal|vauthors=Hillig KW|date=2004|title=A chemotaxonomic analysis of terpenoid variation in Cannabis|journal=Biochemical Systematics and Ecology|volume=32|issue=10|pages=875–891|doi=10.1016/j.bse.2004.04.004|bibcode=2004BioSE..32..875H }} Resin from Pistacia terebinthus (commonly known as terebinth or turpentine tree) is rich in pinene. Pine nuts produced by pine trees contain pinene.
Makrut lime fruit peel contains an essential oil comparable to lime fruit peel oil; its main components are limonene and β-pinene.{{cite journal|vauthors=Kasuan N|date=2013|title=Extraction of Citrus hystrix D.C. (Kaffir Lime) Essential Oil Using Automated Steam Distillation Process: Analysis of Volatile Compounds|url=http://www.ukm.my/mjas/v17_n3/Nurhani.pdf|journal=Malaysian Journal of Analytical Sciences|volume=17|issue=3|pages=359–369}}
The racemic mixture of the two forms of pinene is found in some oils like eucalyptus oil.{{Cite web|title=alpha-Pinene - Compound Summary|url=https://pubchem.ncbi.nlm.nih.gov/compound/alpha-pinene#section=Top|access-date=14 Nov 2017|website=PubChem|publisher=NCBI}}
Reactions
=α-Pinene=
Selective oxidation of α-pinene occurs at the allylic position to give verbenone, along with pinene oxide, as well as verbenol and its hydroperoxide.{{cite journal|vauthors=Neuenschwander U, Guignard F, Hermans I|date=2010|title=Mechanism of the Aerobic Oxidation of α-Pinene|journal=ChemSusChem|language=de|volume=3|issue=1|pages=75–84|doi=10.1002/cssc.200900228|pmid=20017184|doi-access=free|bibcode=2010ChSCh...3...75N }}{{cite journal |doi=10.15227/orgsyn.072.0057|title=(1R,5R)-(+)-Verbenone of High Optical Purity |journal=Organic Syntheses |year=1995 |volume=72 |page=57|author=Mark R. Sivik, Kenetha J. Stanton, Leo A. Paquette }}
Image:Verbenone by oxidation of pinene.png
α-Pinene can be converted to camphor by way of isobornyl acetate.
Hydrogenation of pinene gives pinane, precursor to a useful pinanehydroperoxide.
The hydroboration of α-pinene has been extensively examined. With borane-dimethylsulfide, two equivalents of α-pinene react to give (diisopinocampheyl)borane.{{cite journal |doi=10.15227/orgsyn.092.0026|title=Preparation of Crystalline (Diisopinocampheyl)borane |year=2015 |last1=Abbott |first1=Jason |first2=Christophe|last2=Allais|first3=William R.|last3=Roush|
journal=Organic Syntheses |volume=92 |pages=26–37 |doi-access=free }} Reaction with 9-BBN gives the reagent called alpine borane. This sterically crowded chiral trialkylborane can stereoselectively reduce aldehydes in what is known as the Midland Alpine borane reduction.{{cite journal |last1=Midland |first1=M. Mark |title=B -3-Pinanyl-9-borabicyclo[3.3.1]nonane |journal=Encyclopedia of Reagents for Organic Synthesis |date=15 April 2001 |doi=10.1002/047084289X.rp173|isbn=0-471-93623-5 }}
=β-Pinene=
β-Pinene can be converted to α-pinene in the presence of strong bases,{{cite journal |doi=10.15227/orgsyn.065.0224|title=(a)-b-PINENE BY ISOMERIZATION OF (B)-b-PINENE |journal=Organic Syntheses |year=1987 |volume=65 |page=224|author=Charles A. Brown, Prabhakav K. Jadhav }} or pyrolysed to produce myrcene at 400 °C.
Use
Pinenes, especially α, are the primary constituents of turpentine, a nature-derived solvent and fuel.
The use of pinene as a biofuel in spark ignition engines has been explored.{{Cite journal|vauthors=Raman V, Sivasankaralingam V, Dibble R, Sarathy SM|date=2016|title=α-Pinene - A High Energy Density Biofuel for SI Engine Applications|journal=SAE Technical Paper|series=SAE Technical Paper Series|volume=1|doi=10.4271/2016-01-2171}} Pinene dimers have been shown to have heating values comparable to the jet fuel JP-10.
References
{{reflist}}
Bibliography
- {{cite book|first1=J.|last1=Mann|first2=R. S.|last2=Davidson|first3=J. B.|last3=Hobbs|first4=D. V.|last4=Banthorpe|first5=J. B.|last5=Harborne|title=Natural Products|pages=[https://archive.org/details/isbn_9780582060098/page/309 309–311]|publisher=Addison Wesley Longman Ltd.|location=Harlow, UK|year=1994|isbn=978-0-582-06009-8|url-access=registration|url=https://archive.org/details/isbn_9780582060098/page/309}}