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.[3] Pinenes are also found in many non-coniferous plants such as camphorweed (Heterotheca)[4] and big sagebrush (Artemisia tridentata).
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.[5]
Alpha-pinene is the most widely encountered terpenoid in nature[6] and is highly repellent to insects.[7]
Alpha-pinene appears in conifers and numerous other plants.[8] Pinene is a major component of the essential oils of Sideritis spp. (ironwort)[9] and
Salvia spp. (sage).[10]Cannabis also contains alpha-pinene[8] and beta-pinene.[11] Resin from Pistacia terebinthus (commonly known as terebinth or turpentine tree) is rich in pinene. Pine nuts produced by pine trees contain pinene.[8]
Makrut lime fruit peel contains an essential oil comparable to lime fruit peel oil; its main components are limonene and β-pinene.[12]
The racemic mixture of the two forms of pinene is found in some oils like eucalyptus oil.[13]
β-Pinene can be converted to α-pinene in the presence of strong bases.[14]
Selective oxidation of pinene occurs at the allylic position to give verbenone, along with pinene oxide, as well as verbenol and its hydroperoxide.[15][16]
^Lincoln DE, Lawrence BM (1984). "The Volatile Constituents of Camphorweed, Heterotheca subaxillaris". Phytochemistry. 23 (4): 933–934. doi:10.1016/S0031-9422(00)85073-6.
^Köse EO, Deniz İG, Sarıkürkçü C, Aktaş Ö, Yavuz M (2010). "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". Food and Chemical Toxicology. 48 (10): 2960–2965. doi:10.1016/j.fct.2010.07.033. PMID20670669.
^Özek G, Demirci F, Özek T, Tabanca N, Wedge DE, Khan SI, et al. (2010). "Gas chromatographic-mass spectrometric analysis of volatiles obtained by four different techniques from Salvia rosifolia Sm., and evaluation for biological activity". Journal of Chromatography A. 1217 (5): 741–748. doi:10.1016/j.chroma.2009.11.086. PMID20015509.
^Hillig KW (2004). "A chemotaxonomic analysis of terpenoid variation in Cannabis". Biochemical Systematics and Ecology. 32 (10): 875–891. doi:10.1016/j.bse.2004.04.004.
^Charles A. Brown, Prabhakav K. Jadhav (1987). "(a)-b-PINENE BY ISOMERIZATION OF (B)-b-PINENE". Organic Syntheses. 65: 224. doi:10.15227/orgsyn.065.0224.
^Mark R. Sivik, Kenetha J. Stanton, Leo A. Paquette (1995). "(1R,5R)-(+)-Verbenone of High Optical Purity". Organic Syntheses. 72: 57. doi:10.15227/orgsyn.072.0057.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^M. Mark Midland "B-3-Pinanyl-9-borabicyclo[3.3.1]nonane" in Encyclopedia of Reagents for Organic Synthesis 2001 John Wiley, New York.doi:10.1002/047084289X.rp173
^Raman V, Sivasankaralingam V, Dibble R, Sarathy SM (2016). "α-Pinene - A High Energy Density Biofuel for SI Engine Applications". SAE Technical Paper. SAE Technical Paper Series. 1. doi:10.4271/2016-01-2171.
Mann, J.; Davidson, R. S.; Hobbs, J. B.; Banthorpe, D. V.; Harborne, J. B. (1994). Natural Products. Harlow, UK: Addison Wesley Longman Ltd. pp. 309–311. ISBN978-0-582-06009-8.