Perfume musk synthesis

The latest (1980) commercial application of olefin metathesis is Phillips Neohexene Process ( ). Neohexene, an intermediate in the synthesis of a perfume musk, is produced by cross-metathesis of diisobutylene with ethylene (i,e., ethylene cleavage) over a bifunctional (double-bond isomerization/metathesis) catalyst system (Figure 7) ... 

CifiHjoO. A yellow liquid b.p. 330°C. The perfume base obtained from the scent glands of the Tibetan musk deer also available by synthesis. 

Further important industrial applications of olefin metathesis include the synthesis of 3,3-dimethyl-l-butene ( neohexene , intermediate for the production of musk perfume) from ethene and 2,4,4-trimethyl-2-pentene, the manufacture of a,co-dienes from ethene and cycloalkenes (reversed RCM), and the ROMP of cyclooctene and norbomene to Vestenamer and Norsorex , respectively. 

The classical scent of the sea is afforded by ambergris, which is also the best fixative for perfumes. Once secured from whales, ambergris can now be legally provided by chemical synthesis (Science whaling 2000). Other fixatives are obtained from land animals, such as castoreum, civet, and musk. The first one is a phenolic substance and the latter two macrocyclic ketones that have stimulated the earfy methodologies for the synthesis of macrocyclic conqjoimds... 

Otherwise, in general construction the perfume follows closely that of a classical oriental, with citrus oils (making up some 25%), lavender, sandalwood, patchouli, vanillin, coumarin, castoreum, and rose. The general sweetness of the perfume is further enhanced by the choice of musk materials, Galaxolide (5%), Tonalid, ethylene brassylate, and musk ketone, as well as by the use of Cashmeran, an intensely sweet fruity musk material associated with the synthesis of Galaxolide. 

A variation of the Schmidt type reaction is the rearrangement of an azidocyc-loalkane, which is formed from the addition of hydrazoic acid to an cycloalkene. This reaction was used in the synthesis of muscopyridine (II/U4), a base isolated from the perfume gland of the musk deer [85]. In this context the reaction of II/115 as a model compound under the conditions of the Schmidt reaction gave a mixture of two compounds which after dehydrogenation yielded 11/116 and 11/117. The mechanism can be explained in terms of the migration of different bonds in the precursor. 

Pure meto-cresol has been used for manufacture of synthetic musk— musk ambrette, used as a fixative to perfumes, for manufacture of synthetic Thymol and Menthol amd also leather preservative p-chloro-meto-cresol, synthetic pyre-throids, and lastly for manufacture of 2,3,6-trimethylphe-nol—an intermediate for vitamin E. o-Cresol has been used for manufacture of Coumarin and some derivatives which are employed in perfumery as fixative. o-Cresol has also been used for making Novolac and epoxy resins and also for the herbicides based on di-nitro-oAt/io-cresol, etc. In sum, individual cresols have been very successfully converted to important intermediates in the organic chemical synthesis. It is expected that further development work will lead to synthesis of many more organic chemicals of vital importance. While new chemicals using individual cresols are in the pipeline... 

In the field of fine chemistry, the Phillips neohexene process was an early commercial application of olefin metathesis [20]. Neohexene (3,3-dimethyl-l-butene) is an important intermediate in the synthesis of musk perfume. The Phillips neohexene process is based on ethenolysis of an isobutene dimer consisting of a mixture of 2,4,4-trimethyl-2-pentene and 2,4,4-trimethyl-1-pentene. Ethenolysis of the former yields the desired product (Eq. 6). 

C17H30O, Mr 250.42. Crystals with a sweet animalish, musk-like odor mp. 31-32°C, bp. 103 °C (6.7 Pa), soluble in alcohol and other organic solvents. Occurrence In civet (ca. 3%) together with other macrocyclic ketones. Recognized as the component responsible for the civet odor in 1915 by Sack, structure elucidation in 1926 by Ruzicka, for synthesis, see C. is used in fine perfumes for a flxating musk-like odor. 

C15H28O2, Mr 240.39. cryst. with a fine, musk-like odor.mp. 37-38 C, bp. 176 °C (2 kPa),U)5o(ratp.o.) >5 g/kg. The structure of 15-P. occurring in angelica root/seed oil (ca. 1%) was elucidated in 1927 by Kerschbaum. For synthesis, see Use To an increasing extent as a nature-identical musk fragrance substance in perfume oils and, above all, in fine perfumes. 

As said above, the main application of neohexene is the synthesis of musk perfume components, in two steps. The first step is the alkylation of / -cymene by neohexene and the second a reaction with acetyl chloride ... 

Following is the structural formula of musk ambrette, a synthetic musk, essential in perfumes to enhance and retain odor. Propose a synthesis of this compound from m-cresol (3-methylphenol). 

Dimethyl-I-butene (neohexene), an important intermediate for the synthesis of musk perfumes, is produced on a commercial scale either from diisobu-... 

Cyclododecanone, which became the most accessible of medium-ring ketones following Wilke s discovery of the butadiene-cyclotrimerization process, is an important starting point for manufacture of the valuable musk ketones. Two syntheses of muscone, commencing from cyclododecanone are outlined below. The first synthesis, which emanated jointly from Eshenmoser s group in Zurich and laboratories of the Swiss perfume firm, Firmenich Cie., illustrates a three-carbon ring expansion reaction based on the widely applicable tosylhydrazone version of the oxidoketone— alkynone fragmentation. ... 

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