Sesquiterpene alcohols

The sesquiterpenes found in essential oils have low volatilities compared with monoterpenes and so are isolated mainly by steam distillation or extraction, but some are also isolated by distillation or crystallization. Most of the sesquiterpene alcohols are heavy viscous Hquids and many crystallize when they are of high enough purity. Sesquiterpene alcohols are important in perfume bases for their odor value and their fixative properties as well. They are valuable as carriers of woody, balsamic, or heavy oriental perfume notes. 

Guaiol and Bulnesol. The main constituents of guaicwood oil are the sesquiterpene alcohols guaiol [489-86-1] (107) and bulnesol (108). When the alcohols are dehydrated with acid, many of the hydrocarbons formed are also found ia patchouli oil. 

By con ersion into the xanlbogemc esters Ihe alcoholic porlion of the oil was separated iolo two distinct portions, which on saponification yielded l o isomeric sesquiterpene alcohols. One of ihese. iso-cryptoraeriol, C,jH,jOH, is a liquid of specific relation — 3° 2o. The isomeric alcohol has been termed cryptoraeiiol, and is an oil of specific rotation - 37° o, and has a specific gravity 0 96d. 

Thi oil contains, in o-ddition to cuoalyptol. I-pinene, Mimonene. an alcoboi, tt sesquiterpene alcohol, a sesquiterpene (. j, and bef 7aldehyde ( j,... 

In addition to cucalyptol, the oil contains heuealdehyde (. ) I-pincnii Mimonene, dipcntene, and a sesquiterpene alcohol, which has been termed melaleucol, Ii is suggesled that this alcohol may be related to the alcohol iierolidol, in the same way as geraniol is to linalol. The idenlity ol this body, however, is hardly established bv experimental... 

Phenyl i-ibyl alcohol has recentlv beeii shown to he a normal constituent of otto of rose, but it appears to he mostly, if not entirely lust or dsstroveil by the Bulgarian method of rlisiillation. Nerol ifi also present in small amount as well as, probably, faroesol. a sesquiterpene alcohol CijH.,0, present in oil of cassie flowers. Eiigeuol, linalol, and nonyliu aldehyde arc also present in traces. 

Semmler has detected a small qnaotitv of a sesquiterpene alcohol, and a phenol ether to which he assigned the name elemicin. This body h 3 a specific grariiy 1-063 at 30, refractive index 1 3365, aud boils at 144 to 147 - at lO mm. 

Caryophyllene nitrosochloride, (CjgHgJjN OoCL, is obtained when a mixture of the sesquiterpene, alcohol, ethyl acetate, and ethyl nitrite is cooled in a freezing mixture, and then treated with a saturated solution of hydrochloric acid in alcohol. The reaction mass is allowed to stand on ice for an hour and is then exposed to sunlight. Thus prepared it melts at about 158° to 163°, and can be separated into two compounds, one being that of a-caryophyllene and the other that of yS-caryophyllene Deussen s sesquiterpenes of natural caryophyllene from clove oil), a-caryophyllene nitrosochloride melts at 177", and /3-caryophyllene nitrosochloride at 159°. They can be separated by fractional crystallisation. The corresponding a-nitrolbenzylamine melts at 126° to 128°, and the /3-nitrolbenzylamine at 172° to 173°. The bimolecular formula given above is probable but not certain. 

Gadamer and Amenomiya have prepared a well-defined sesquiterpene vhich they term atractylene, by dehydrating atractylol, a crystalline sesquiterpene alcohol separated from the oil of Atractylis ovata. It is an oil with an odour of cedar wood, and is prohahly bicyclic. It polymerises on keeping and has the following characters —... 

By dehydrating guaiol, the sesquiterpene alcohol present in guaiac wood oil, Wallach and Tuttle obtained a bicyclic sesquiterpene which they called guaiene. It has been obtained by different methods by other observers from guaiol, and its characters are recorded as follows... 

Tapia has prepared this bicyclic sesquiterpene by distilling capar-rapiol, the sesquiterpene alcohol present in caparrapi oil, with phosphoric ai ydride. It is a colourless oil having the following characters —... 

Semmler and Mayer have isolated from the oil of cedar wood an alcohol, pseudocedrol. There also exists in the oil a sesquiterpene alcohol, cedrol. The latter, on dehydration yields cedrene, which is probably identical with, or very closely allied to, natural cedrene, whilst pseudocedrol yields a mixture, when heated in a sealed tube, of cedrene and dihydrocedrene. Dihydrocedrene is a colourless oil having the following characters —... 

This sesquiterpene has not been found naturally. It is formed by the dehydration of the so-called patchouli camphor, a sesquiterpene alcohol, CjjHjgO, found in oil of patchouli. It has the following characters —... 

Schimmel Co. have isolated a sesquiterpene alcohol from Samoan resin, known as Maali resin, and by dehydrating it by means of formic acid have obtained a sesquiterpene which has not been named other than as Maali sesquiterpene. It has the following characters —... 

The next group of alcoholic bodies to be studied are those which, although open-chaini alcohols, show considerable tendency to easily pass into closed-chain compounds, so that they occupy a definite position of their own, midway between the ordinary aliphatic series and the closed-chain series. The principal members of this important group are geraniol, nerol, linalol, and citronellol, together with the so-called aliphatic sesquiterpene alcohols, farnesol and nerolidol. 

Farnesol, CjsH gO, is an aliphatic sesquiterpene alcohol, which occurs in ambrette seed oil, and flower oils of the type of acacia, lime flowers, mignonette, and lilac flowers. 

It is evident from these reactions that farnesol has the constitution of an aliphatic sesquiterpene alcohol with three double bonds, and that-its formula is—... 

There exist in sandalwood oil (from Santalum album) two isomeric sesquiterpene alcohols, of the formula CjjHg O. They are both primary UDSaturated alcohols, one being bicyclic, the other tricyclic. These two alcohols are termed a-santalol and /3-santalol. a-santalol has the following characters —... 

Cedrol, Cj H gO, is a true sesquiterpene alcohol occurring in cedar-wood oil (Juniperus virgtniana) and several allied essential oils. 

Semmler and. lonas have isolated a sesquiterpene alcohol, from oil of galbanum. It yields a hydrochloride melting at 117° to 118°. 

Brooks has isolated from the fraction of oil of ginger boiling at 151° to 157° at 15 mm. an alcohol which he finds to be a sesquiterpene alcohol, CjsH gO, corresponding to the sesquiterpene zingiberene. It has the fragrant odour of ginger, and probably possesses one of the following constitutions —... 

Guaiol, CjgHjgO, is an odourless sesquiterpene alcohol found in the essential oil of the wood of Bulnesia Sarmienti, known as guaiac wood oil. 

Semmler and Mayer have isolated a sesquiterpene alcohol, from the high boiling fractions of oil of cloves.. It was probably not obtained in an absolutely pure condition, but had the following characters, which must be regarded as approximate only —... 

It yields a chloride, CjjHjgCl, of specific gravity 0-990 at 20°. a bicyclic sesquiterpene alcohol, with one double bond. 

Ledum camphor, CjgHjgO, is a solid sesquiterpene alcohol present in the essential oil of Ledum palustre. It forms long, colourless needles having the following characters —... 

Semmler and Feldstein have isolated a sesquiterpene alcohol, P, from the oil of costus root, to which they have given the name costol. It was purified by conversion into its acid phthalate, which, on hydrolysis yields the pure alcohol, having the following characters —... 

Costol is a diolefinic bicyclic sesquiterpene alcohol, which, on oxidation by chromio acid in acetic acid yields an aldehyde, CjgH jO, which jrields a semi-carbazone, melting at 217° to 218°. This aldehyde, which U triolefinic has the following characters —... 

On reduction elemol yields tetrahydroelemol, CigHg O. Elemol is a monocyclic sesquiterpene alcohol, and on dehydration yields the sesquiterpene elemene. 

Ramsay 1 has isolated a crystalline sesquiterpene alcohol from the essential oil distilled from the bark of the juniper tree. It forms optically inactive triclinic crystals, melting at 107°, and having the formula CjjH O. 

This sesquiterpene alcohol was discovered by Schimmel Co. in oil of Eucalyptus globulus. It is found in the last fractions of the distillate, separating out in crystalline condition. On recrystallisation from 70 per cent, alcohol, it was obtained in the form of brilliant, almost odourless needles, having the following characters —... 

Schimmel Co. attempted to acetylise the alcohol by means of acetic anhydride, but the reaction product only showed 5 per cent, of ester, which was not submitted to further examination. The bulk of the alcohol had been converted into a hydrocarbon, with loss of water. Ninety per cent, formic acid is most suitable for splitting off water. Gne hundred grams of the sesquiterpene alcohol were heated to boiling-point with three times the quantity of formic acid, well shaken, and, after cooling, mixed with water. The layer of oil removed from the liquid was freed fi-om resinous impurities by steam-distillation, and then fractionated at atmo.spheric pressure. It was then found to consist of a mixture of dextro-rotatory and laevo-rotatory hydrocarbons. By repeated fractional distillation, partly in vacuo, partly at ordinary pressure, it was possible to separate two isomeric sesquiterpenes, which, after treatment with aqueous alkali, and distillation over metallic sodium, showed the following physical constants —... 

Cubeb camphor, CuHjgO, is a sesquiterpene alcohol which is found in oil of cuhebs, especially in old samples of the oil. It is laevo-rotatory, melts at 68° to 70°, and boils at 248° with decomposition. Nothing is known of its constitution. 

This sesquiterpene alcohol is found in old samples of Matico leaf oil. It is a crystalline body, of the formula, CjgHjgO, melting at 94°, and of specific rotation — 28-73°, in chloroform solution. 

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