Farnesene

Chembox new
Name = ("E","E")-α-Farnesene
ImageFile = A-Farnesene.svg
ImageName = Farnesene
IUPACName = α: 3,7,11-trimethyl-1,3,6,10-dodecatetraene
Section1 = Chembox Identifiers
SMILES = α: CC(C)=CCCC(C)=CCC=C(C)C=C
β: CC(C)=CCCC(C)=CCCC(C=C)=C
Section2 = Chembox Properties
Formula = C₁₅H₂₄
MolarMass = 204.36 g/mol
MeltingPt =
BoilingPt = α-("Z"): 125 at 12 mmHg
β-("E"): 124 °C
β-("Z"): 95-107 at 3 mmHg The term farnesene refers to a set of six closely related chemical compounds which all are sesquiterpenes. α-Farnesene and β-farnesene are isomers, differing by the location of one double bond. α-Farnesene is 3,7,11-trimethyl-1,3,6,10-dodecatetraene and β-farnesene is 7,11-dimethyl-3-methylene-1,6,10-dodecatriene. The alpha form can exist as four stereoisomers that differ about the geometry of two of its three internal double bonds (the stereoisomers of the third internal double bond are identical). The beta isomer exists as two stereoisomers about the geometry of its central double bond.

Two of the α-farnesene stereoisomers are reported to occur in Nature. ("E","E")-α-Farnesene is the most common isomer. It is found in the coating of apples, and other fruits, and it is responsible for the characteristic green apple odour. Its oxidation by air gives compounds that are damaging to the fruit. The oxidation products injure cell membranes which eventually causes cell death in the outermost cell layers of the fruit, resulting in a storage disorder known as scald. ("Z","E")-α-Farnesene has been isolated from the oil of perilla. Both isomers are also insect semiochemicals; they act as alarm pheremones in termites [Citation
author = Šobotník, J., Hanus, R., Kalinová, B., Piskorski, R., Cvačka, J., Bourguignon, T., Roisin, Y.
title = [http://www.springerlink.com/content/86l627g32132m157/?p=f59bab83a40442a6a5074441490b63ec&pi=5 ("E","E")-α-Farnesene, an Alarm Pheromone of the Termite "Prorhinotermes canalifrons"]
journal = Journal of Chemical Ecology
volume = 34
pages = 478–486
date = April 2008] or food attractants for the apple tree pest, the codling moth [Citation
author = Hern, A. & Dorn, S.
title = [http://www.springerlink.com/content/j36363180422584k/?p=f0cc1c90b6b24dfbbf8c87bd2ac84282&pi=2 Sexual dimorphism in the olfactory orientation of adult "Cydia pomonella" in response to alpha-farnesene]
journal = Entomologia Experimentalis et Applicata
volume = 92
pages = 63 - 72
date = July 1999] . α-Farnesene is also the chief compound contributing to the scent of gardenia, making up ~65% of the headspace constituents [Citation |first1 = Shau-Chun |last1=Wang| first2=Ting-Yu| last2=Tseng| first3=Chih-Min| last3=Huanga| first4=Tung-Hu|last4=Tsaic| title= Gardenia herbal active constituents: applicable separation procedures| journal=Journal of Chromatography B| volume=812| issue= 1-2|date=5 December 2004|year=2004|pages193-202] .

β-Farnesene has one naturally occurring isomer. The "E" isomer is a constituent of various essential oils. It is also released by aphids as an alarm pheremone upon death to warn away other aphids [Citation
author = Gibson, R. W. & Pickett, J. A.
title = [http://www.nature.com/nature/journal/v302/n5909/abs/302608a0.html Wild potato repels aphids by release of aphid alarm pheromone]
journal = Nature
volume = 302
pages = 608 - 609
date = 14 April 1983] . Several plants, including potato species, have been shown to synthesize this pheromone as a natural insect repellent [Citation
author = Avé, D. A., Gregory, P., Tingey, W. M.
title = [http://www.springerlink.com/content/v2t2484177514520/?p=99bc57ed4d0f45c9a698dbe4b6e2e877&pi=3 Aphid repellent sesquiterpenes in glandular trichomes of "Solanum berthaultii" and "S. tuberosum"]
journal = Entomologia Experimentalis et Applicata
volume = 44
pages = 131 - 138
date = July 1987] .

ee also

* Farnesol
* Nerolidol

References