Sesquiterpenic alcohols

Sesquiterpene alcohol Sesquiterpene alkaloids Sesquiterpene glucosides... 

Sesquiterpenic alcohol Sesquiterpene hydrocarbons Sesquiterpene lactones... 

Lentinus sp. Aromatic, fruity Higher alcohols, sesquiterpenes... 

Sesquiterpene alcohols Sesquiterpene alcohols are not commonly found in essential oils but, like bis-abolol (found in the German chamomile) are antiallergen, anti-inflammatory, and can also act as liver and glandular stimulants. Other essential oils that contain sesquiterpene alcohols are sandalwood oil (the active alcohol being a-sanatol, the structure of which is included in F ure 4), oil of ginger, patchouH oil, vetiver oil, and carrot seed oil. 

Perfumes are composed of hundreds of aromatic chemicals, namely, fragrance chemicals, or just simply fragrances. Among these compounds, it is very common to find compounds with the characteristic five-carbon isoprene unit, giving them the names of terpenes, such as terpene aldehydes, monoterpene alcohols, sesquiterpene alcohols, terpene ketones, terpene esters, monoterpene hydrocarbons, or sesquiterpene hydrocarbons. In addition, other compounds, such as aldehydes, alcohols, ketones, esters, phenols, or lactones, are also very common. 

It has been found that the flavor of fmit can be increased by a process called precursor atmosphere (PA) (77). When apples were stored in a controlled atmosphere containing butyl alcohol [71-36-3] the butyl alcohol levels increase by a factor of two, and the polar products, butyl ester, and some sesquiterpene products increase significantly. The process offers the possibiUty of compensating for loss of flavor in fmit handling and processing due to improper transportation conditions or excessive heat. 

Terpenes are characterized as being made up of units of isoprene in a head-to-tail orientation. This isoprene concept, invented to aid in the stmcture deterrnination of terpenes found in natural products, was especially useful for elucidation of stmctures of more complex sesquiterpenes, diterpenes, and polyterpenes. The hydrocarbon, myrcene, and the terpene alcohol, a-terpineol, can be considered as being made up of two isoprene units in such a head-to-tail orientation (1). 

The majority of the turpentine comes from the southeastern United States, which consists of 60—70% a-pinene, 20—25% P-pinene, and 6—12% other components. Because there is variation in components from different species of the pine tree as well as variation from the many paper pulp mills, there is obviously variation in the analysis of sulfate turpentines. Some of the other components consist of -menthadienes, alcohols, ethers such as anethole [104-46-1] and methylchavicol [104-67-0] and the sesquiterpene hydrocarbon, P-caryophyUene [87-44-5]. 

Important commercial sesquiterpenes mosdy come from essential oils, for example, cedrene and cedrol from cedarwood oil. Many sesquiterpene hydrocarbons and alcohols are important in perfumery as well as being raw materials for synthesis of new fragrance materials. There are probably over 3000 sesquiterpenes that have been isolated and identified in nature. 

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. 

Gedrene and Gedrol. Cedarwood oil is one of the essential oils whose production is large and provides a source for synthesizing a number of derivatives. Gedrene (91) and thujopsene (92) are the two main sesquiterpene hydrocarbons found in the oil, along with a number of minor components (187). Gedrol [77-53-2] (93) is the main alcohol component of the oil. 

Patchouli alcohol. Patchouli oil comes from Pogostemonpatchouli and the main constituent is patchouli alcohol [5986-55-0] (105) or patchoulol. Another component of the essential oil is norpatchoulenol (106), a norsesquiterpene derivative as a minor (3—5%) constituent, important ia determining the overall odor of the essential oil (197). The price of patchouli oil ia 1995 was 20.90/kg from Indonesia (69). Alarge proportion of the oil (40—60%) is comprised of sesquiterpene hydrocarbons that do not have much odor value. World production of the oil was at about 750 t ia 1984. It is valuable ia perfumery bases because of its characteristic woody, herbaceous odor (198). 

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. 

Mondello et al. (54) have developed some applications of on-line HPLC-HRGC and HPLC-HRGC/MS in the analysis of citrus essential oils. In particular, they used LC-GC to determine the enantiomeric ratios of monoterpene alcohols in lemon, mandarin, bitter orange and sweet orange oils. LC-GC/MS was used to study the composition of the most common citrus peel, citrus leaf (petitgrain) and flower (neroli) oils. The oils were separated into two fractions, i.e. mono- and sesquiterpene... 

The oil contains about 60 per eeiit. of sesquiterpenes and 10 per cent, of seaqoiterpene alcohols. The principal sesqnileipcne ia probably cadinene, as indicated hy the following figures in comparison with those for eodinene obtained fvom oil of cade —... 

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. 

It is convenient to here mention the hydrocarbon verbenene, C,gH,4, on account of its relationship with pinene. It results from the action of acetic anhydride on verbenol, thei alcohol corresponding with the ketone, verbenone. So produced it is laevo-rotatory. The dextro-rotatory and racemic varieties are also known. The sesquiterpenes have the following characters when regenerated from their respective dibromides —... 

Zingiberene also forms a nitrosate, C,5H24. N2O4, when the sesquiterpene dissolved in an equal volume of glacial acetic acid, is cooled to 0°, and ethyl nitrite, and then nitric acid added. The nitrosate is dissolved in acetic ether and precipitated with alcohol. It forms a yellow powder, melting with decomposition at 86°. 

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. 

Caryophyllene nitrosite is an interesting compound. It has the formula CJ5H24N2O3, and was first produced by Schreiner and Kremers. It is form by treating a mixture of equal volumes of the sesquiterpene and petroleum ether with a concentrated solution of sodium nitrite and glacial acetic acid. It crystallises in fine blue needles when re-crvstallised from alcohol it melts at 115° and has a specific rotation -h 103°. 

The most recent work, however, on the sesquiterpene is that of fiemmler and Eisse. From the crude selinene, prepared hy fractional distillation, they prepared the crystalline dihydrochloride, Cj5H24.2HC1, melting at 72° to 74°, by passing a mixture of 1 part of dry hydrochloric acid gas with 3 parts of air, into the sesquiterpene dissolved in ether. This compound on digestion at very gentle heat, with a solution of caustic potash in methyl alcohol, yields selinene, which the authors conclude is a doubly unsaturated bicyclic compound. The characters of the selinene thus obtained are as follows —... 

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... 

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