Natural fragrances

This brief listing of reactions, not including oxyacylations, ought to demonstrate the broad applicability of palladium reagents in synthetic organic chemistry. These reactions are used in multistep syntheses to produce pharmaceuticals, fragrances, natural products, etc., and are documented in recent publications. Surveys are given in many review articles and books [50-53, 136-148]. 

Fragrances Natural Advantage http //www.naturai-advantage.net, Penta Mfg. http //www.pentamfg. com Wutong Aroma http //www.wu-tong.com... 

Storage Store in cool, dry place keep tightly closed keep away from heat, open flame Uses Fragrance natural flavoring agent in foods... 

Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating fumes Storage Keep cool, well closed protect from light Uses Fragrance natural flavoring agent in foods and pharmaceuticals mfg. of terpeneless lemon oil Use Level ADI 500 pg/kg (WHO)... 

Mondello L., 2011, Flavour and Fragrance Natural and Synthetic Compounds 2, 2nd edn. John Wiley Sons, Ltd., Chichester, U.K. 

Applications of chromatography/FT-IR spectroscopy involve toxins and carcinogens, waste-water constituents, sediment extracts, airborne species, pesticides and their degradation products, fuels and fuel feedstocks, flavors and fragrances, natural products, pharmaceuticals, biomedicine, and polymers. 

However, despite the considerable efforts devoted to address the fundamental issues toward the development of asymmetric protonation, its applications to natural or bioactive synthesis remain sporadic. Herein, two main strategies, namely the enantioselective protonation of metal enolates, especially silicon enolates and the protonation of polar double bonds, i.e., Michael acceptors, were depicted trough the most relevant synthetic applications. These two strategies led to the synthesis of fragrance, natural products, ° bioactive compoundsand... 

Several manuals devoted, at least in part, to flavor formulation have been published (52—63), eg, literature from the Fragrance Materials Association of the United States, Washington, D.C. The increasing number of materials available has resulted in the improvement of flavor characteristics and has permitted a closer rendition of natural flavors. Often such materials bear a scant sensory relationship to the tme natural flavor character. When used as a component and judiciously applied, these materials serve a useful purpose in a properly compounded flavor. 

Specifications also appear in other pubHcations, including pubHcations of the Fragrance Materials Association (FMA) of the United States (53,57) (see also Fine chemicals). The FMA specifications include essential oils, natural flavor and fragrance materials, aromatic chemicals, isolates, general tests, spectra, suggested apparatus, and revisions adopted by the FMA. 

Applications. The most ubiquitous use of infrared spectrometry is chemical identification. It has long been an important tool for studying newly synthesi2ed compounds in the research lab, but industrial identification uses cover an even wider range. In many industries ir spectrometry is used to assay feedstocks (qv). In the flavors (see Flavors and spices), fragrances (see Perfumes), and cosmetics (qv) industries, it can be used not only for gross identification of feedstocks, but for determining specific sources. The spectra of essential oils (see Oils, essential), essences, and other natural products vary with the season and source. Adulteration and dilution can also be identified. 

Experimental procedures have been described in which the desired reactions have been carried out either by whole microbial cells or by enzymes (1—3). These involve carbohydrates (qv) (4,5) steroids (qv), sterols, and bile acids (6—11) nonsteroid cycHc compounds (12) ahcycHc and alkane hydroxylations (13—16) alkaloids (7,17,18) various pharmaceuticals (qv) (19—21), including antibiotics (19—24) and miscellaneous natural products (25—27). Reviews of the microbial oxidation of aUphatic and aromatic hydrocarbons (qv) (28), monoterpenes (29,30), pesticides (qv) (31,32), lignin (qv) (33,34), flavors and fragrances (35), and other organic molecules (8,12,36,37) have been pubflshed (see Enzyp applications, industrial Enzyt s in organic synthesis Elavors AND spices). 

Rose. Of all the natural oils, rose is probably the most desired material used in the fine fragrance industry. For years chemists have tried to unravel the mystery of the odor-donating components of this high priced natural material. Simple glc analysis shows that nine components constitute nearly 89% of the total volatiles of rose otto (9) (see Table 2). 

Of all these, probably P-phenethyl alcohol (2) comes closest to the odor of fresh rose petals however, mixing all these components does not reproduce the total fine character of the natural oil. It has been determined that a number of trace constituents representing less than 1% of the volatiles are critical to the development of the complete rose fragrance (10). These include cis- and trans-i.ose oxide (1), nerol oxide (12), rose furan (13), /)i7n7-menth-l-en-9-al (14), P-ionone (15), P-damascone (16), and P-damascenone (3). 

Sometimes a skilled peifumei detects a sandalwood-musky note in authentic Bulgarian otto of rose. This note has been identified (11) as the trace iagredient, 7-methoxy-3,7-dimethyl-2-octanol [41890-92-0] (17), which has been commercially available for some time as Ossyrol (trademark of Bush, Boake, Aken Inc). This compound had never before been identified ia nature, but demonstrates how, sometimes, synthetic fragrance chemists can anticipate nature. 

As early as 1967, IFF chemists (11), in an in-depth study of jasmin absolute, identified an ultratrace amount of one of the key compounds in the entire fragrance repoitoire, hydroxycitroneUal [107-75-7] (21). This chemical has been used for many years in almost every "white flower" fragrance to give a very diffusive and lasting lily-of-the-valley and jasmin note, but this represents the only known identification of the compound in nature. This illustrates that the human nose can often predict the presence of a molecule well before the instmmentation becomes sufficiently sensitive to detect it. 

The irones (167,168,169), which constitute slightly more than 75% of the volatiles, are primarily responsible for the fine odor of the natural material. For this reason and because of the high cost of orris absolute, synthetic versions of the irones have been commercialized. Of the possible irone stmctures, the y-isomer (168) possesses the best fragrance properties. 

Wintergreen Oil. Water distillation of the leaves of Gaultheriaprocumbens L. yields an oil which consists of essentially one chemical constituent, methyl saUcylate. Because of this, the oil has been almost totally replaced by the synthetic chemical. Natural oil of wintergreen [68917-75-9] is a pale yellow to pinkish colored mobile Hquid of intensely sweet-aromatic odor and flavor. The oil or its synthetic replacement find extensive use in pharmaceutical preparations, candy, toothpaste, industrial products, and in rootbeer flavor. In perfumery, it is used in fougnre or forest-type fragrances. 

Odor perception and description are highly subjective in nature. Nevertheless, there is a generally agreed-upon odor vocabulary that is used to characterize individual ingredients and finished fragrances. Table 1 shows some commonly used odor descriptors grouped into five general classifications. 

Aldehydic Floral Family. This is an important family of fragrances, the typical odor of which is the class odor of the aldehydes. The aldehydes are present in small quantities in nature and have an uimatural brilliance. Although they have sharp, slightly fmity odors alone, they blend beautifully and unexpectedly in florals. 

Woody Family. The perfumer has available many different woody fragrance matetials, both natural and synthetic. Naturals such as sandal, vetivert, cedar, and patchouh often form the bases of these fragrances. They combine iu harmony with sweet notes, florals, and animal accords. 

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