Farnesyl alcohol

AI3-44561 Dihydrofarnesol 2,6,10-Dodecatrien-1-ol, 3,7,11-trimethyl- EINECS 225-004-1 EPA Pesticide Chemical Code 128911 Farnesol Farnesyl alcohol FCI 119a FEMA No. 2478 HSDB 446 NSC 60597 Stirrup Stirrup-A/WF Stirrup-CRW Stirrup-H Stirrup-HB Stirrup-TPW Trimethyl dodecatrienol 3,7,11-Trimethyt-2,6,10-dodecatrienol 3,7,11-Trimethyl-2,6,10-dodecatrien-... 

Synonyms 2,6,10-Dodecatrienol, 3,7,11-trimethyl- Farnesyl alcohol Trimethyl dodecatrienol 3,7,11-Trimethyl-2,6,10-dodecatrien-1-ol... 

Farnesyl alcohol. See Farnesol Pascal 2004] Pascal 2005. See Stannous chloride anhydrous Pascal 4400. See Stannic chloride Fast acid magenta. See Acid red 33 Fast blue. See Dianisidine Fast blue 7GLN. See Direct blue 218 Fast brown RR salt. See 2,6-Dichloro-p-phenylenediamine... 

Hydrolysis of the pyrophosphate ester group converts farnesyl pyrophosphate to the corresponding alcohol farnesol (see Figure 26 6 for the structure of farnesol)... 

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. 

The use of chiral dirhodium carboxamidates has made possible the highly enantioselective synthesis of presqualene alcohol (4) from farnesyl diazoacetate (14) through cyclopropane 15 [9] (Eq. 1). Highly enantiomerically en-... 

The bisabolanes, of which eight have been reported in these studies, also deserve special mention. Again, Z,E-farnesyl pyrophosphate is the putative progenitor. One study (13) reported 3-bisabolol (199) to be about 34% of the volatile alcohol fraction, making it about 5% of the total essential oil. a-Bisabolene (193) is representative of the hydrocarbons of this group. 

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]. 

The all-tra 5 -squalene (C30H50), discovered in shark liver oil in the 1920s, is a triterpene, but one in which the isoprene rule at violated in one point. Rather than a head-to-tail arrangement of six units of isoprene, there appear to be farnesyl units that have been connected tail to tail. Almost aU steroids are biosynthesized from cholesterol. Cholesterol is biosynthesized from squalene, which is first converted to lanosterol. The conversion of squalene to the steroid skeleton is an oxirane, squalene-2,3-oxide, which is transformed by enzymes into lanosterol, a steroid alcohol naturally found in wool fat. The whole process is highly stereoselective. 

An efficient and inexpensive method for the substitution of an allylic hydroxyl group with fluorine, without allylic rearrangement and elimination consists of treating an allylic alcohol with methyllithium followed by p-toluenesulfonyl fluoride, lithium fluoride and 12-crown-4.6 By this method, geranyl fluoride, neryl fluoride, cinnamyl fluoride, ( , )-farnesyl fluoride, retinyl fluoride and 4-fluoro-2-methyl-6-(4-tolyl)hept-2-ene are prepared. 

Several papers report new findings on ubiquinone biosynthesis. A mitochondrial membrane-rich preparation from baker s yeast can convert 4-hydroxybenzoate and isopentenyl pyrophosphate into the ubiquinone precursor 3-all-trans-hexaprenyl-4-hydroxybenzoate (234). Details of the cell-free system are presented. With preformed polyprenyl pyrophosphates, the system catalysed the polyprenylation of several aromatic compounds, e.g. methyl 4-hydroxybenzoate, 4-hydroxybenzaldehyde, 4-hydroxybenzyl alcohol, and 4-hydroxycinnamate. No evidence was obtained for the involvement of 4-hydr-oxybenzoyl-CoA or 4-hydroxybenzoyl-S-protein in the reaction. With shorter-chain prenyl pyrophosphates a shorter prenyl side-chain was introduced, e.g. geranyl and farnesyl pyrophosphates gave products with a 3-diprenyl and 3-triprenyl side-chain respectively. A crude enzyme preparation from E. coli... 

The method used by Coates and Robinson" involved the copper-catalysed decomposition of trans,trans-farnesyl diazoacetate (4) to the cyclopropyl-lactone (5) having the stereochemistry shown. This was transformed into the cis-aldehyde-ester (6) by standard methods. Base epimerization gave the more stable transcompound (7). A Wittig reaction between the trans-aldehyde-ester (7) and the phosphorane (8), followed by lithium aluminium hydride reduction, yielded presqualene alcohol (1) as the major product accompanied by the minor isomer (9). 

The third synthesis, by Crombie et al., utilizes the base-catalysed condensation of the trans,trans-phenyl farnesyl sulphone (10) with trans,trans-Qthy farneso-ate to give the ester (11) as a major product via the intermediate (12). Lithium aluminium hydride reduction again yielded presqualene alcohol (1). In each case the labelled synthetic alcohol, as its pyrophosphate, was incorporated by yeast subcellular particles into squalene in ca. 68 % yield. The minor synthetic isomers were not incorporated. 

The controversy over presqualene alcohol has been resolved in favour of Rilling s second structure (5), rather than the diester proposed by Popjak or the acyclic formulation suggested by Lynen. In the biosynthesis from farnesyl pyrophosphate one hydrogen atom is lost to the medium from C-1, and when the presqualene alcohol pyrophosphate is further metabolized to squalene (6) no further hydrogen atoms are lost. Final proof of the structure came from its synthesis by three groups the indicated absolute stereochemistry was based on a correlation with trans-chrysanthemyl alcohol. This structure is now also accepted by Popjak and co-workers. Thus the conversion of farnesyl pyrophosphate into squalene may be rationalized as shown (see also ref 29). 

C-racemization of phosphorothioylated/phosphorylated amino acids (Scheme 23). An oxathiaphospholane approach to one-pot phosphorothioylation of isoprenoid alcohols such as allyl, geranyl, isopentenyl, citronellyl, farnesyl, and phytyl alcohols has also been reported (Scheme 24). ... 

A new synthetic approach to the synthesis of germacrane sesquiterpenoids involving cyclization of 10,ll-epoxy-rran5,trans-farnesyl phenyl sulphide (306) provides a mixture of hedycaryol (307) and the isomeric alcohols (308) and (309). Studies on the biosynthesis of germacrane sesquiterpenoids have appeared recently. 

The consistency of the high levels of enantiocontrol accessible in these diazoester cyclizations is underpinned by their growing applications in enantiose-lective synthesis of bioactive molecules containing cyclopropane units. Notable examples include the preparation of multifunctional cyclopropanes as peptide isosteres for renin inhibitors (Scheme 4) [42] presqualene alcohol from farnesyl diazoacetate (Scheme 5) [43] the GABA analogue 3-azabicyclo[3.1.0]hexan-2-one from N-allyldiazoacetamide, Eq. (26) [23] and precursors of lR,3S)-cis-chrysanthemic acid and the pheromone, E-(-)-dictyopterene C (Scheme 6) [44, 45],... 

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). 

In the second approach (B), because of a low initial yield in the first method, the acid-catalysed reaction of the phenol in dioxane containing boron trifluoride etherate with the prenyl alcohol was used. In this way 2-geranyl, 2-farnesyl, 2-phytyl and 2-nonaprenylphenol were obtained in unstated yields, accompanied by the 4-isomer in each case. In the third strategy (C) the prenyl bromide was... 

Reaction of geranyl pyrophosphate with isopentenyl pyrophosphate yields the 15-carbon farnesyl pyrophosphate, the precursor of all sesquiterpenes. Far-nesol, the corresponding alcohol, is found in citronella oil and lemon oil. 

In his 1968 review, Stedman (3797) divided the alcohols into three categories, namely, alcohols, sterols, and oxygenated isoprenoid constituents. The latter category contained constituents other than those with an alcoholic hydroxyl group, for example, farnesyl acetone (a ketone), solanach-romene (a phenol), the tocopherols (phenols), and the levan-tanolides and levantenolide (ether-lactone combinations). In the category usually considered alcohols, Stedman listed a total of twenty-five alcohols (fifteen aliphatic, two aromatic, five polyols, and three cyclic). 

In this synthesis farnesyl bromide (25) was converted with 2-nitropropane and KOH into farnesal (27). Horner-Emmons reaction with the C -phosphonate 28 gave the ester 29 which was reduced with LiAlH4 to the alcohol 30 (32% yield referred to 25) and transformed, with phosphorus tribromide and triphenylphosphine, to the C2o-phosphonium salt 31 (Scheme 7). 

Isomerization of farnesyl pyrophosphate is believed to involve reversible dephosphorylation with the formation of the corresponding alcohols and may proceed via 6-trans-farnesyl aldehyde. 

Scheme 11.53. A cartoon representation of a potential pathway to aristolone from farnesyl diphosphate.The pattern of methylation anticipated has changed due to (presumably) a series of hydride and methide shifts. The structure of aristolochic acid, one of the few nitro-containing natural products known is also shown since some sesquiterpene alcohols are found as esters.

---