Farnesyl acetate

Farnesol forms an acetate, farnesyl acetate, which is a nearly odourless oil, boiling at 169° to 170° at 10 mm. 

B. l0-Bromo-ll-hydroxy-10,ll-dihydrofarnesyl Acetate [2,6-Dodeca-diene-1,11-diol, 10-bromo-3,7, -trimethyl-, 1-acetate, (E,E)-]. Farnesyl acetate (29 g., 0.11 mole) is dissolved in 1 1. of /erf-butyl alcohol (Note 4) contained in a 3-1. Erlenmeyer flask. Water is added (500 ml.), and the solution is cooled to about 12° using an external ice water bath. Maintaining this temperature, rapid magnetic stirring is begun, and more water is added until a saturated solution is obtained. The second addition of water may be rapid initially, but the saturation point must be approached carefully, like the end point of a titration. A total of about 1200 ml. of water is required for the above amounts of farnesyl acetate and ferf-butyl alcohol. The solution must remain clear and homogeneous at about 12°, and if the saturation point is accidentally passed by adding too much water, ferf-butyl alcohol should be added to remove the turbidity. 

Concentration of the ethereal solution at reduced pressure gives the epoxyacetate as a colorless oil more viscous than water. The overall yield based on farnesyl acetate is near 60% (Note 11). This material is reasonably pure if the preparation has been executed carefully, but it can be further purified by column chromatography (Note 12) or distillation (Note 13). 

Fractions may be monitored by thin-layer chromatography on silica gel, developing with 10% v/v ethyl acetate in hexane and visualizing with iodine vapor. The following Rf values were observed famesol, 0.07 farnesyl acetate, 0.35 bromohydrin acetate, 0.20. 

An intramolecular cycloaddition of the tetradecatrienyl nitroethyl ether 263 was used in the synthesis of the 14-membered bicyclic precursor 265 of crassin acetate 266, a cembrane lactone possessing antibiotic and antineoplastic activity (332). Nitro compound 263 was obtained from farnesyl acetate (262) in several steps and was then treated with phenyl isocyanate and triethylamine to give the tricyclic isoxazoline 264 (Scheme 6.98). Conversion to ketone 265 was accomplished by hydrogenation of the cycloadduct with Raney Ni and boric acid followed by acetylation (332). In this case, the isoxazoline derived from a 3-butenyl nitroethyl ether moiety served to produce a 3-methylenetetrahydropyran moiety (332). 

Other components are acyclic aliphatic esters and terpenes, such as farnesol and farnesyl acetate [237-239a]. Ambrette seed oil is one of the most expensive essential oils and, thus, is used mainly in fine fragrances and in alcoholic beverages. FCT 1975 (13) p.705 [8015-62-1], [84455-19-6]. 

Ambrette seed Hibiscus abelmoschus L. (Z)-7-Hexadecan-16-olide, ambret-tolide (8-9), 5-tetradecen-14-olide, (2f ,6f )-farnesyl acetate (39-59)... 

Upon irradiation in acetonitrile/aqueous solution, of 1-cyanonaptha-lene in presence of all trans-farnesyl acetate, the latter undergoes only cis-trans isomerization via an electron transfer process. No products from any other reactions were isolated. However, when the same combination of... 

Oxidative polycyclizations with, for example, RuOa catalysts can be carried out with polyene substrates as complex as farnesyl acetate, geranylgeranyl acetate, and squalene. The f , f , /ra j,/ra r,/ra r-configuration of the penta-tetrahydrofuranyl diol product resulting from the oxidation of squalene (Scheme 57) has been determined by nuclear magnetic resonance (NMR) spectroscopy <2005T927>. 

A mixture of trans, traits- and cis, fran.r-isomers, or pure trans, /rons-farnesyl acetate. 

C17H2802 trans.trans-farnesyl acetate 4128-17-0 494.90 43.394 2 30370 C17H37N methylhexadecylamine 13417-08-8 594.15 53.000 1.2... 

The ring-closure mechanism of 2-chloroethanol has been studied on the basis of kinetic and equilibrium chlorine isotope effects. Epoxidation of the terminal double bond of farnesyl acetate has been achieved via the bromohydrin, obtained with NBS. A stereospecific method has been elaborated for the preparation of 1-alkynyloxiranes, starting from the monotosylate ester of acetylenic diols. 1-Alkynyloxiranes are also formed from a-hydroxy quaternary ammonium salts in alkaline medium (Eq. 57). ... 

The total synthesis of (+)- -onocerin via four-component coupling and tetracyclization steps was achieved in the laboratory of E.J. Corey. The farnesyl acetate-derived acyl silane was treated with vinyllithium, which brought about the stereospecific formation of a (Z)-silyl enol ether as a result of a spontaneous Brook rearrangement. In the same pot, the solution of I2 was added to obtain the desired diepoxide via oxidative dimerization. 

Farnesyl acetate (trans-trflns-3,7,ll-trimethyl-2,6,10-dodecatrien-l-yl acetate) [4128-17-0... 

The saturated long-chain fatty acids are discussed in Section 5.E, therefore we include some corresponding esters, but not, for example, linoleic esters or esters of long-chain alcohols that are not in Section 5.B. For example, ethyl linoleate and farnesyl acetate have been identified in green Mexican arabica by Cantergiani et al. (2001). 

Dodecatrien-1-ol,3,7,11-trimethyl-, acetate farnesyl acetate 2.6.10- Dodecatrien-1-ol, 3,7,11-trimethyl-, formate farnesyl formate 1063-1066,1068-1074 1590a, 3547, 3549, 4249 3547, 4249 ... 

Komal et (Ref. 53) found gc-ms evidence of the sesquiterpenes 6 sellnene (54), methyl farnesate, farnesyl acetate (55), and farnesol (56) present In an Inhibitory fraction Isolated from water nutgrass (Cyperus serotinus ). This fraction at 300 ppm Inhibited lettuce germination and also Inhibited growth of lettuce and rice seedlings as well as nutgrass Itself. The authors conclude that the sesquiterpenes are responsible for the observed allelopathlc effects. 

Dodecatrien-l-ol, 3,7,11-trimethyl-, E,Ey] (Note 1) and 40 ml. of dry pyridine (Note 2) is prepared in a stoppered 250-ml. Erlenmeyer flask, and 40 ml. of acetic anhydride is added in four portions over a 15-minute period. The mixture is stirred well and allowed to stand for 6 hours and then poured onto 250 g. of ice. Water is added (400 ml.), and the mixture is extracted with five 100-ml. portions of petroleum ether (b.p. 60-68°). The organic extracts are combined and washed in succession with two 50-ml. portions each of water, 5% aqueous sulfuric acid, and saturated aqueous sodium bicarbonate. Anhydrous magnesium sulfate [ca. 50 g.) is used to dry the petroleum ether solution, which is then concentrated on a rotary evaporator to provide 28-29 g. (94-98%) of farnesyl acetate as a colorless oil (Note 3). 

External cooling is now discontinued, and 21.4 g. (0.12 mole) of W-bromosuccinimide[2,5-Pyrrolidinedione, 1-bromo-] (Note 5) is added. Stirring is continued until all of the solid is dissolved ca. 1 hour). The resulting solution, which may be pale yellow, is concentrated with a rotary" evaporator (bath temperature 40-45°) to a volume of about 300 ml. and extracted with five 120-ml. portions of ether. The combined ether extracts are dried over anhydrous magnesium sulfate (20-50 g.), and removal of solvent at reduced pressure provides an oil, which is purified by column chromatography on silica gel (Note 6). Pure bromo-hydrin acetate is obtained as a colorless oil in amounts of up to 26 g., a 65% yield based on farnesyl acetate (Notes 7 and 8). 

Production By steam distillation from seeds of Abel-moschus moschatus (Malvaceae), a hibiscus species growing in the tropics. Origin India, South America. Composition The main component is farnesyl acetate (50-60%) (C HjgOj, Mr 264.41), accompanied by some famesol (3-5%). TTie typical odor and taste determining component is ambrettolide. 

Farnesyl acetate SCHEME 5 Successive polyolefinic cyclizations. 

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