Farnesene

The Farnesene ( emphasis on the third syllable: Farnesene ) form a group of substances which includes six closely related compounds from the class of sesquiterpenes. α - farnesene and β - farnesene are isomers with different positions of the double bond. In α - farnesene is 3,7,11 -trimethyl-1 ,3,6,10 - dodecatetraene, while β - farnesene the formula 7,11 -dimethyl- 3-methylene -1 ,6,10 - dodecatrien has. From the alpha form, there are four configurational isomers, the double bonds with respect to the geometry of both internal distinction ( at the terminal double bonds there is no way to isomerism ). The beta - isomer, there are two isomers differ in the configuration of their central double bond.

α - farnesene

Two of the configurational isomers of α - Farnesens were isolated as natural products.

(E, E)- α - farnesene, is the more common of the two. It is found for example in the bowl of apples and other fruits and is the recipient of the characteristic " green apple flavor ." Oxidation by air leads to compounds that ultimately lead to cell death of the outer cell layers of the fruit, such as can be observed on the brown discoloration at pressure points of apples.

(Z, E)- α - farnesene was isolated from the essential oil of Perilla. Both isomers act on insects as messengers; they act as alarm pheromones in termites or as an attractant in the codling moth.

α - farnesene is still the main component of the Gardenienöls ( from gardenia ) with a share of about 65 % of the volatile components.

The other two isomers are technically producible.

β - farnesene

From the β - farnesene been an isomer in nature was detected.

E-isomer is a component of various ethereal oils. It is released by aphids as an alarm pheromone to warn other aphids. It has been shown that various plants, such as some types of potato used as a natural pheromone this repellent against insects.

The Z isomer has been shown only artificially.