Гeraniol

Описание

Geraniol has a characteristic rose-like odor. Geraniol may be prepared by fractional distillation from those essential oils rich in geraniol, or synthetically from myrcene; commercial geraniol cannot be classified according to its alcohol content, as most of the recurring impurities are alcoholic in nature (nerol, citronellol, tetrahydrogeraniol). Gas-chromatography techniques may be usefully employed to determine the geraniol content in a product.

Химические свойства

Geraniol occurs in nearly all terpene-containing essential oils, frequently as an ester. Palmarosa oil contains 70–85% geraniol; geranium oils and rose oils also contain large quantities. Geraniol is a colorless liquid, with a floral, rose-like odor.
Since geraniol is an acyclic, doubly unsaturated alcohol, it can undergo a number of reactions, such as rearrangement and cyclization. Rearrangement in the presence of copper catalysts yields citronellal. In the presence of mineral acids, it cyclizes to form monocyclic terpene hydrocarbons, cyclogeraniol being obtained if the hydroxy function is protected. Partial hydrogenation leads to citronellol, and complete hydrogenation of the double bonds yields 3,7-dimethyloctan-l-ol (tetrahydrogeraniol). Citral may be obtained from geraniol by oxidation or by catalytic dehydrogenation. Geranyl esters are prepared by esterification.
Geraniol is one of the most frequently used terpenoid fragrance materials. It can be used in all floral, rose-like compositions and does not discolor soaps. In flavor compositions, geraniol is used in small quantities to accentuate citrus notes. It is an important intermediate in the manufacture of geranyl esters, citronellol, and citral.

Вхождение

The presence of geraniol in nature has been reported in more than 160 essential oils: ginger grass, lemongrass, Ceylon and Java citronella, tuberose, oak musk, orris, champaca, ylang-ylang, mace, nutmeg, sassafras, Cayenne Bois-de-Rose, Acacia farnesiana, geramium clary sage, spike, lavandin, lavender, jasmine, coriander, carrot, myrrh, eucalyptus, lime, mandarin petitgrain, bergamot petitgrain, bergamot, lemon, orange and others The essential oils of palmarosa and Cymbopogon winterianus contain the highest levels of geraniol (approx 80 to 95%) Also reported in numerous other sources including apple juice, citrus peel oils and juices, bilberry, cranberry, other berries, guava, papaya, cinnamon, ginger, corn mint oil, mustard, nutmeg, mace, milk, coffee, tea, whiskey, honey, passion fruit, plums, mushrooms, mango, starfruit, cardamom, coriander leaf and seeds, litchi, Ocimum basilicum, myrtle leaf, rosemary, clary sage, Spanish sage and chamomile oil

Использование

Geraniol is used in the synthesis of insect repellant. It is also used in the synthesis of Angelicoin A and Herecinone J, which inhibit collagen-induced platelet aggregation.

Определение

ChEBI: A monoterpenoid consisting of two prenyl units linked head-to-tail and functionalised with a hydroxy group at its tail end.

Общее описание

Colorless to pale yellow oily liquid with a sweet rose odor.

Профиль реактивности

An unsaturated aliphatic hydrocarbon and an alcohol. Flammable and/or toxic gases are generated by the combination of alcohols with alkali metals, nitrides, and strong reducing agents. They react with oxoacids and carboxylic acids to form esters plus water. Oxidizing agents convert them to aldehydes or ketones. Alcohols exhibit both weak acid and weak base behavior. They may initiate the polymerization of isocyanates and epoxides.

разработк И противоопухолевых препаратов

Starting from antitumor activity against several cell lines by an arrest occurring atthe G0/G1 cell cycle and ultimately with an increase of apoptosis, this molecule wasfound to interfere with the mevalonic cycle enzyme. Suppression of prenylation ofproteins leads to the inhibition of DNA synthesis, and the suppression of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) leads to a reduction of the mevalonate pool andthus limits protein isoprenylation. In the same way, a reduction of cholesterol biodisponibilitywas controlled (Pattanayak et al. 2009; Ni et al. 2012; Dahham et al.2016).

Профиль безопасности

Poison by intravenous route. Moderately toxic by ingestion, subcutaneous, and intramuscular routes. A severe human skin irritant. Combustible liquid. When heated to decomposition it emits acrid smoke and irritating fumes.

Метаболизм

Geraniol is metabolized in the rabbit by ω-oxidation and by reduction of an α β-unsaturated bond (Parke, 1968). The products of geraniol metabolism are 'Hildebrandt acid' and 7-carboxy-3-methylocta-6-enoic acid. The latter acid is optically active (Williams, 1959).

Методы очистки

Purify geraniol 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 purify it by GLC on a silicone-treated column of Carbowax 20M (10%) on Chromosorb W (60-80 mesh). [Porter Pure Appl Chem 20 499 1969.] Store it in full, tightly sealed containers in the cool and protect from light. It has a pleasant odour. [cf p 681, Beilstein 1 IV 2277.]