Cedarwood

Two main families of cedarwood oils are used in perfumery. The first is extracted from trees of the family Juniperus. These oils are known as 

English, Texan or Chinese Cedarwood and their components are derived from the cedrane and thujopsane groups of sesquiterpenoids. Atlas and Himalayan cedarwoods are obtained from Cedrus species and their terpenoids are mostly from the bisabolane family. The cedrane/thujopsane derivatives are much more widely used than the bisabolanes. 

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In 1993, the United States imported nearly 22 x 10 kg of essential oils at a total value of almost 190 x 10 , an increase over 1992 of ca 2.3 X 10 kg and 935,000. Table 1 fists the quantities and values of 35 imported essential oils. The United States exports seven principal essential oils orange, lemon, peppermint, spearmint, cedarwood, clove, and nutmeg. The latter two are not grown in the United States but are imported as dried spice, processed for oil, and then exported. 

Ced rwood. Many varieties of cedarwood oil are obtained from different parts of the world. They are produced mainly by steam distillation of chipped heartwood, but some are also produced by solvent extraction. The oils, which vary significantly ia chemical composition, are used ia perfumes as such, but the main uses are as distillation fractions and chemical derivatives. For the latter purposes the most used oils, which are similar ia composition, are from Texas ia the United States (Juniperus mexicand) and from China Cupressusfunebris). The principal constituents of these oils are cedrene [11028-42-5] (4), thujopsene [470-40-6] (5), and cedrol [77-53-2] (6). The first two of these are obtained together by distillation and used mostiy ia the form of acetylated derivatives. Cedrol is used as such and, to a greater extent, as its acetate ester. 

Many other compounds are presendy in use a 1993 database search showed 27 active ingredients in 212 products registered by the U.S. EPA for human use as repellents or feeding depressants, including octyl bicycloheptene dicarboxamide (A/-2-ethylhexylbicyclo[2.2.1]-5-hepten-2,3-dicarboxamide), dipropyl isocinchomeronate (2,5-pyridine dicarboxyhc acid, dipropyl ester), dimethyl phthalate, oil of citroneUa, cedarwood oil, pyrethrins, and pine tar oil (2). Repellent—toxicant or biting depressant systems are available which are reasonably comfortable for the user and can protect completely against a number of pests for an extended period of time (2). 

Myrcene with its conjugated diene system readily undergoes Diels-Alder reactions with a number of dienophiles. For example, reaction with 3-meth.5i-3-pentene-2-one with a catalytic amount of AlCl gives an intermediate monocyclic ketone, which when cyclized with 85% phosphoric acid produces the bicycHc ketone known as Iso E Super [54464-57-2] (49). The product is useful in providing sandalwood-like and cedarwood-like fragrance ingredients (91). 

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. 

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. 

Skita has studied the reduction of ionone by means of palladium chloride. The reduction-product, dihydroionone, boils at 121° and 122° (14 mm.) it possessed a faint odour of cedarwood. By the same method, /3-ionone yields a dihydroionone boiling at 126° to 129° (12 mm.). When the reduction is continued until hydrogen ceases to be absorbed, both a- and j8-ionone yield tetrahydroionone, boiling at 126° to f27°... 

Many cyclic sesquiterpene alcohols are key odor components in essential oils, for example, cedrol in cedarwood oil, the vetiverols in vetiver oil, and the santalols in sandalwood oil. Since these alcohols have not yet been synthesized on an industrial scale, they are described under the oil in which they occur (Chapter 3). Some of their derivatives, however, are discussed in this section. 

C17H26O, Mr 246.39, is a long-lasting wood fragrance which is prepared by acetylation of cedarwood oil fractions that contain sesquiterpene hydrocarbons, mainly a-cedrene and thujopsene. Acetylation is carried out in the presence of an acidic... 

Chinese cedarwood oil is similar in composition to Texas cedarwood oil (see below). Chinese cedarwood oil is obtained by steam distillation of Chamaecyparis funebris (Endl.) France (Cupressusfunebris Endl., Cupressaceae), which is a weeping cypress, indigenous to China. Commercial Chinese cedarwood oil is a colorless to slightly yellow oil with an odor more smoke-like than the American oils. 

Texas cedarwood oil is produced by steam distillation of chopped wood of the Texas cedar, Juniperus mexicana Schiede (Cupressaceae). It is a brown to reddish-brown, viscous liquid that may partially solidify at room temperature. It has a characteristic cedarwood odor. 

Cedarwood Cupressus funebris Endl. Cedrol (10-16), a-cedrene... 

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