Geraniol acetate

DIMETHYL-2,6-OCTADIEN-8-YL ETHANOATE FEMA No. 2509 GERANIOL ACETATE GERANYL ACETATE (FCC) NCI-C54728... 

Synonyms Acetic acid geraniol ester (E)-3,7-Dimethyl-2,6-octadien-1-ol acetate trans-3,7-Dimethyl-2,6-octadien-1-ol acetate 3,7-Dimethyl-2-trans-6-octadienyl acetate trans-2,6-Dimethyl-2,6-octadien-8-yl ethanoate Geraniol acetate 2,6-Octadien-1-ol, 3,7-dimethyl-, acetate 2,6-Octadien-1-ol, 3,7-dimethyl-, acetate, (E)-Definition Found in oils of Daucus carota. Eucalyptus macarthurii, etc. or obtained from geraniol by acetylation Empirical C12H20O2 Formula ... 

The (2jR)-absolute configuration of natural aleuriaxanthin was first deduced by application of a modified Horeau technique 137) and has subsequently been corroborated by a stereospecific total synthesis of the pigment in both enantiomeric modifications 220). The natural enantiomer (450) was produced from the optically active epoxygeraniol derivative (469), itself obtained from geraniol acetate by allylic hydrox-ylation followed by Sharpless asymmetric epoxidation (Scheme 71) 220). 

The possibilities of 1-methylcyclobutene as an isoprene equivalent have again attracted attention. Reaction of methylcyclobutene with -3-hexene catalysed by tungsten hexachloride and tetramethyltin gave the metathesis product (319) in ca. 25 % yield as a mixture of isomers. In a similar reaction with geraniol acetate, small amounts of farnesol acetate were detected. 

Acid-catalyzed esterification of nerol and geraniol with acid anhydrides produces the corresponding esters. The acetates and isobutyrates are also avaUable commercial products. U.S. production of neryl acetate [141-12-8] in 1993 was 18 t at a price of 11.56/kg and that of geranyl acetate [105-37-3] was 132 t at a price of 9.86/kg (67). 

Linalool can also be made along with nerol and geraniol via the hydrochlorination of myrcene. After conversion of the chlorides to acetates followed by saponification of the acetates, the mixture of alcohols is obtained. Fractionation of the mixture gives linalool in about 95% purity, but the presence of close boiling impurities prohibits manufacture of a perfiimery-quahty product. 

Uses ndReactions. Linalool can be estetified to linalyl acetate by reaction with acetic anhydride. Linalyl acetate [115-95-7] has a floral-fmity odor, reminiscent of bergamot and lavender. The price of the acetate in 1995 was 14.30/kg (45). Linalool is subject to dehydration and to isomerization to nerol and geraniol during the esterification. However, if the acetic acid formed during the esterification is removed in a distillation column, the isomerization can be minimized and good yields of the acetate obtained (130). 

Geraniol [106-24-1] M 154.3, b 230 , d 0.879, n 1.4766. Purified by ascending chromatography or by thin layer chromatography on plates of kieselguhr G with acetone/water/liquid paraffin (130 70 1) as solvent system. Hexane/ethyl acetate (1 4) is also suitable. Also purified by GLC on a silicone-treated column of Carbowax 20M (10%) on Chromosorb W (60-80 mesh). [Porter Pure Appl Chem 20 499 7969.] Stored in full, tightly sealed containers in the cool, protected from light. 

Geranyl acetate (a diene) takes up 2 moles of hydrogen unselectively in 48 hours to give the saturated acetate, 3,7-dimethyloctyl acetate, bp 109-110712 mm, 1.4261. (Geraniol itself has an allylic hydroxyl and appears to suffer decarbonylation under these reaction conditions.)... 

Myrtenol, CjpHjgO, is a primary cyclic alcohol, which was isolated from essential oil of myrtle, in which it occurs principally in the form of its acetic ester, by von Soden and Elze. It is separated from geraniol, with which it is found, by fractional distillation, and by the crystallisa-... 

The Oximation process depends on the fact that citronellal oxime, produced by shaking in the cold with a solution of hydroxylamine, is converted on heating with acetic anhydride into a nitrile which is not affected by saponification with alcoholic potash. The difference between the molecular weight of the nitrile formed and that of citronellal is so small as to be negligible, and the calculation of the percentage of geraniol from the saponification value is made by the usual formula. The method of procedure is as follows —... 

Acetylation.—Gitronellal may be quantitatively estimated by the ordinary acetylation process i when the aldehyde is quantitatively converted into isopulegyl acetate, which is then determined by saponification with potash in the ordinary way. Dupont and Labaume have attempted to base a method for the separation of geraniol from citronellal in citron-ella oils on the fact that the citronellal oxime formed by shaking with hydroxylamine solution at the ordinary temperature is not converted into an ester by subsequent acetylation, but into the nitrile of citronellic acid which is stable towards" alkali during the saponification process. 

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