Ethers, famesyl

Dodecatrien-1-ol, 3,7,11-trimethyl-, (E,E)-] (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-mi. 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 famesyl acetate as a colorless oil (Note 3). 

External cooling is now discontinued, and 21.4 g. (0.12 mole) of A-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 famesyl acetate (Notes 7 and 8). 

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 famesyl 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). 

Marriott JH, Moreno Barber AM, Hardcastle IR, Rowlands MG, Grimshaw RM, Neidle S, Jarman M. Synthesis of the famesyl ether 2,3,5-trilluoro-6-hydroxy-4-((E,E.-3,7,ll-trimethyldodeca-2,... 

Gotsypol an aromatic triterpene from cotton seed (Gossypum hirsiuum). M, 518.54, m.p. 184°C from ether, 199"C from chloroform, 214°C from light petroleum. G. is biosynthesized from mevalonic acid via neryl pyrophosphate and cisjcis-famesyl pyrophosphate. It is somewhat poisonous, and has been suggested for use as an insecticide. 

Obtained by reaction of chloromethyl methyl ether with 3-famesyl-2,4,6-tri-hydroxyacetophe-none in the presence of potassium carbonate in refluxing... 

Imaging/Labeling Applications Alcohols aloesin analytes bile acid A-acetylglucosaminides carnitine enantiomers corticosteroids cortisol cortisone famesyl pyrophosphate (FPP) hydroxy steroids archaeal ether core lipids A-terminal peptide segment of myosin subfragment-1 (S-1) serine-181 thyroid hormones triamcinolone (TMC) ... 

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