Perfumery ingredients

Upon treatment with aluminum ethoxide, the aldehyde is converted to cinnamyl cinnamate [122-69-0] (Tishchenko reaction), a valuable perfumery ingredient. 

Zeolites have been shown to catalyse a variety of related reactions (Downing et al., 1997), e.g. zeolite beta catalyses the synthesis of coumarins via the Pechmann condensation. For example, condensation of resorcinol with ethyl acetoacetate over zeolite beta in refluxing toluene gave methylumbelliferone, a perfumery ingredient, in 70-80% yield (Fig. 2.24) (Gunnewegh ef a/., 1996). 

These can be the natural material itself one example would be pieces of vanilla pod or an extract, e.g. vanilla extract. Extracts can be prepared in several ways. One is to distil or to steam distil the material of interest. Another is to extract the raw material with a solvent, e.g. ethyl alcohol. Alternatively, some materials are extracted by coating the leaves of a plant with cocoa butter and allowing the material of interest to migrate into the cocoa butter. These techniques are also used in preparing perfumery ingredients, indeed materials like orange oil are used in both flavours and perfumes. 

RIFM Research Institute for Fragrance Materials. Important for testing and advising on safety of perfumery ingredients and relevant to essential oils. 

The sp values of most perfumery ingredients fall between ca. 16 MPa0,5 (non-polar materials such as terpene hydrocarbons) and ca. 25 MPa0,5 (polar materials such as alcohols). In general, we expect materials to have lower activity coefficients in microenvironments characterized by similar values of sp. For instance, limonene (sp value of 16.5) is expected to be compatible with plastics such as polyethylene... 

Modern natural product analysis reveals both the chemical composition of new oils or flower scents and the identity of novel fragrant molecules that may become new perfumery ingredients in the future. It is chemical detective work to solve the mysteries of nature s fragrances that have evolved over the millennia. 

By reaction of phenols with bifunclional molecules, which are able to alkylate and to esterify, several coumarin derivatives have been prepared using H-Bela as the catalyst. Thus resorcinol and propynoic acid react at 150 °C in p-chlorotolucnc as the solvent towards the perfumery ingredient umbelliferone (7-hydroxycoumarin) in good yield, 60 %, [84], Amberlyst-15 gave 40 % yield. II-Beta catalyzes the esterification as well as the ring closure alkylation step. 

Another route to coumarins is the Pechmann condensation of phenols with (3-ketoesters. The reaction proceeds via transesterification and intramolecular hydroxyalkylation, followed by dehydration, and is conventionally conducted using sulfuric acid as catalyst. Resorcinol and ethyl acetoacetate reacted sol vent-free over H-beta at 150 °C to give 7-hydroxy-4-methylcoumarin (78 % isolated yield) [85J. This is another perfumery ingredient which is also an intermediate for the insecticide I Iymecromone. 

Nature remains a great source of inspiration for chemists and many of today s perfumery ingredients, drugs and agricultural chemicals are replicates (nature identical) of natural terpenoids or close analogues of them. 

Citral is the key odoriferous principle of lemon and lemongrass oils and is therefore potentially useful in perfumes and flavours. More importantly, citral is a key intermediate in many synthetic routes to the ionones (a group of perfumery ingredients which will be described more fully in Chapter 8) and vitamins A, E and K. The synthesis of Barbier, Bouveault and Tiemann served its purpose as confirmation of the structure of citral. However, in terms of preparing large amounts of material for commercial use or even for use as an intermediate in further laboratory syntheses, it is somewhat lacking. This will be discussed in detail in Chapter 9 for the present suffice it to say that the need for an efficient synthesis of citral stimulated much synthetic effort over the years. 

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... 

Figure 9.21 shows a more extensive product tree and this would be the representative of a major chemical company with interests in both the perfumery ingredients and pharmaceutical markets. Perhaps this company was initially interested in the synthesis of vitamins as part of their activity in the pharmaceutical industry. The initial targets were... 

Nature serves as a wonderful inspiration for discovery chemists in all application areas. Folk medicine, such as European herbal remedies and Indian Ayurvedic medicine, has supplied many good leads for modern pharmaceutical agents. Similarly, the natural oils and resins used in traditional perfumery have been the source of inspiration for many modern perfumery ingredients. The basic approach used is to seek out a natural material with a traditional use, analyse it to identify the active chemicals which it contains and then reproduce them in the laboratory and eventually the factory. 

The important perfumery ingredient dihydromyrcenol (P7.1) can be prepared by hydration of dihydromyrcene (P7.2), but the isomeric alcohol (P7.3) is formed as a by-product as shown in Figure P7. Write a mechanism to account for the formation of (P7.3) and suggest ways of producing only dihydromyrcenol. 

Simple, acid-catalysed dehydration of an >-hydroxy-acid under conditions of high dilution has been used in a synthesis of the expensive perfumery ingredient (Z)-5-tetradecen-14-olide, and also in the final step of a synthesis of ( )-decamine/ °... 

Pamplewood is a Firmenich SA perfumery ingredient displaying both grapefruit and woody notes [40]. Such diversity in olfactive properties is indeed due to the presence of both exo and endo isomers in final ingredient (see Fig. 9). 

Occurs in oil from Chamaecyparis lawsonia. Perfumery ingredient. Cryst. Mp 44.5°. Bpioo 184-185°, Bp22 142-143°. 

Found in various plant sources inch cassava, rice, Cannabis sativa. Also found in cider, stale beer and wood ant secretions. Acts as an insect pheromone and may also be a pheromone in humans. Perfumery ingredient. Liq. with sharp, pleasant odour. Bp 190-192°, Bp22 91-92°. Polymerises readily with H2SO4. Oxidised fairly rapidly in air. 

The methyl ester of salicylic acid is encountered commonly in essential oils and is especially abundant in the oil of wintergreen (Gaultheria procumbens, Ericaceae). Methyl salicylate occurs as a glycoside but is hydrolyzed upon injury to the plant. This ester is widely used as a flavoring in candies and as a perfumery ingredient. It is a major component of liniments and is reputed to have antirheumatic properties. 

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