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外観
無色～わずかにうすい黄色, 澄明の液体
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定義
本品は、次の化学式で表されるテルペンアルコールである。
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溶解性
エタノール、アセトン及びクロロホルムに溶けやすく、水にほとんど溶けない。
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解説
ゲラニオール
化学式 C10H17OH 。非環式モノテルペンに属するアルコール。ゲラニオールはトランス形で，沸点 230℃。シス形はネロールと呼ばれ，沸点 225℃である。いずれも植物精油中に含まれる。ゲラニオールは水に不溶，アルコール，エーテルとは混り合う油状液体で，ばら油，ゼラニウム油，シトロネラ油に主成分として含まれ，ばら香をもつ香料として重要。また，ゲラニルピロリン酸エステルはテルペノイド，カロテノイド，ステロイドなどの生合成中間体と考えられている。
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用途
合成香料であり, とくにバラ系調合香料,誘引剤
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用途
有機合成原料、香料材料。
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用途
ゲラニオールローズ香を有する代表的非環式モノテルペンアルコール。パロマローザ油、ゼラニウム油、シトロネラ油など多くの植物精油の主成分であり、ゼラニウム油から得られるアルコールとしてゲラニオールと命名された また、シトラス（レモン、ライムなどの柑橘(かんきつ)類）、ティー、フルーツ、タバコなどのフレーバーにも用いられ、ヨノン、ビタミンEおよびAの製造原料でもある。ゲラニオールの立体構造はtrans(E)-型である。その立体異性体であるネロールの立体構造はcis(Z)-型であり、天然に存在するが、香調が異なり使用量は少ない。
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化粧品の成分用途
香料
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説明
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.
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化学的特性
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.
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天然物の起源
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
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使用
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.
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定義
ChEBI: A monoterpenoid consisting of two prenyl units linked head-to-tail and functionalised with a hydroxy group at its tail end.
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工業的に製造
現在では合成品のゲラニオールが主流であり、次の3種のプロセスによって工業的に製造されている。
(1)アセトン・アセチレン法（ロッシュ法） アセトンとアセチレンを出発原料として合成する。工程は長いが、収率がよく、生成物の精製も容易である。
(2)イソプレン法（クラレ法） 石油C5留分から得られるイソプレンを出発原料とし、塩化プレニル、メチルヘプテノン、リナロールを経てゲラニオールを合成する。
(3)α(アルファ)-ピネン法（グリドコGlidco社） テレビン油から大量に得られるα-ピネンを原料としてリナロールを合成し、これを異性化してゲラニオールを合成する。
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一般的な説明
Colorless to pale yellow oily liquid with a sweet rose odor.
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反応プロフィール
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.
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抗がん研究
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).
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安全性プロファイル
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.
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代謝
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).
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純化方法
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.]
