Acetylated cedarwood

The major components of the Cedrus wood oils are cedrol, cedrene and thujopsene, and a number of perfume ingredients are made from these. The most important is acetylated cedarwood. This product is used because it possesses a much stronger cedarwood odour than the natural oil and is available under various trade names such as Lixetone and Vertofix . The acetylation can be carried out using acetyl chloride in the presence of a Lewis acid or by using a Bronsted acid system such as polyphos-phoric acid/acetic anhydride or sulfuric acid/acetic anhydride. The cedrol dehydrates into cedrene under the reaction conditions and so the major component in the product is acetylcedrene. However, the main contributor to the odour of the complex reaction product mixture is the ketone derived from acetylation of thujopsene (Daniker et al., 1972). These reactions are shown in Figure 4.36. 

Acetylated Cedarwood Oil is a valuable perfumery ingredient. It is prepared by acetylating the entire oil and the major component is therefore usually acetylcedrene. In fact, the mixture is often referred to as acetylcedrene. However, Cedarwood Oil contains many components and... 

As far as the odour of acetylated Cedarwood Oil is concerned, the most important component of the mixture is not derived from cedrene (6.91) at all, but from the next most significant hydrocarbon in the natural oil, thujopsene (6.92). In fact thujopsene accounts for almost as much of the oil as does cedrene, both being present at about 30%. Thujopsene also occurs in Hibawood Oil (Thujopsis dolobrata), of which it is the major component. It is therefore not surprising that acetylated Hibawood Oil has a very intense smell of cedar. 

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. 

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... 

The synthesis of Vertofix (acetyl cedrene) from cedarwood in the early 1960s marked a major step forward in perfumery chemistry, providing perfumers with a fine woody material at a reasonable price, which could be used not only to replace the very much more expensive vetiver derivatives but also had an excellent performance in many functional products such as soaps and shampoos. It is interesting also to find in Fidji a small amount of PTBCHA (Vertenex), another relatively new material at that time, and one more frequently associated with functional products. Here it acts as a link between the woody notes and the fresh green top note. 

Although essential oils or their fractions are mixtures of many substances, these oils are occasionally converted as a whole into derivatives. Examples of such derivatives are vetiveryl acetate from vetiver oil, guaiyl acetate from guaiac wood oil, and acetyl cedrene from cedarwood terpenes. These products are also employed as fragrance substances. 

CijHjfiO, Mr 222.37, mp. 86-87°C, [a]g +10.5° (CHCI3). C. constitutes the actual fragrance substance of cedarwood oil it is often found in cypress oils, sometimes in juniper species (red cedar). C. is the main component in the oil of Juniperus chinensis. To increase the valuable woody, balmy notes, the alcoholic components of cedarwo oil are esterified (e g-, 0-acetyl-C.=cedryl acetate). C. and cedrene-con-taining distillates serve as fixatives for soap perfumes, pine scents, and for perfumes with a woody note in general. 

---