Musk ketone

Still later Baur has shown that if an acetyl group is introduced into the butyl toluene molecule, and the methyl ketone thus formed is nitrated, artificial musk (ketone musk) is produced. One part of butyl toluene, 10 parts of carbon disulphide, and 6 parts of aluminium chloride are cooled in a flask and 6 parts of acetyl chloride are run in quickly. After distillation on a water-bath, the residue is poured on to ice and treated in the usual manner. The acetyl derivative is obtained as an oil with a pleasant aromatic odour, boiling at 255° to 258°, of the formula—... 

Cyclohexadecen-l-one can be added to perfume compositions as a substitute for the natural macrocyclic ketone musks. 

Nitromusks, 117. 121. 126. 231. See also Musk ambrette, Musk ketone, Musk xylene... 

Some of the widely used synthetic fixatives are amyl benzoate, phenethyl, phenyl acetate, cinnamic alcohol esters, acetophenone, musk ambrette, musk ketone, musk xylols, vanillin, coumarin, etc. [41]. 

G-Dinitro-S terf.-butyl-d-aceto-m-xylene (2 4- Dinitro - 6 - tert.- tyl - 6 - acetyl - m-xylene, " Ketone Musk )... 

Galaxolide, tonalide, phantolide, musk ketone, musk xylene DEBT (N,N-diethyl-3-toluamide)... 

Musk Baur Musk Xylene Musk Ketone Musk Ambrette... 

Musk ketone is 4-ter/-butyl-2,6-dimethyl-3,5-dinitroacetophenone, yellow crystals, m.p. 135-136°C. 

Other commonly occurring chemical groups ia essential oils iaclude aromatics such as P-phenethyl alcohol, eugenol, vanillin, ben2aldehyde, cinnamaldehyde, etc heterocycHcs such as iadole (qv), pyra2iaes, thia2oles, etc hydrocarbons (Liaear, branched, saturated, or unsaturated) oxygenated compounds such as alcohols, acids, aldehydes, ketones, ethers and macrocyclic compounds such as the macrocyclic musks, which can be both saturated and unsaturated. 

Since muscone (101), by itself, does not reproduce the total odor impression of this musk, IFF chemists (56) as early as 1971 in an analysis of tincture of Tonquin musk, reported a series of macrocycHc ketones (Table 16) which play a key role in creating the characteristic odor of this musk (11). The introduction of a double bond into a macrocycHc ketone (eg, 102) changes the odor from flowery musk to animal musk. 

In addition to large-scale process work, there is also some effort expended in providing synthetic methods for producing small amounts (<100 kg/yr) of materials needed for replacement of naturals that are being discontinued or in short supply. Examples are ambrinol (59) and dihydro-y-ionone (60) for the replacement of ambergris. More recendy, tincture of tonquin musk has been replaced by using, among other materials, mixtures of macrocyclic ketones and alcohols which have been found in the natural substance. 

Two ketones of unknown constitution have been isolated from natural musk. Of these, muskone, CjgH gO (or Cj Hg O), occurs to the extent of 0 5 to 2 per cent. It is a thick, colourless oil with a very powerful odour of musk. It boils at 327° to 330° at 752 mm., and at 142° to 143° at 2 mm. It yields an oxime melting at 46° and a semi-carbazone melting at 133° to 134°. 

There are a number of nitro-compounds known under the name of artificial musk, all of which may conveniently be grouped together here. The natural odorous constituents of musk appear to be, in the main, ketonic compounds free from nitrogen, so that the term artificial musk must be understood to mean artificially prepared bodies, having musklike odours, but not having any direct chemical relationship with natural musk perfume. 

MK Musk ketone (3,5-dinitro-2,6-dimethyl-4-ferf-butylacetophenone)... 

Consider a quaternary liquid mixture, neroli oil, geraniol, citronellol and solvent, having different volatilities. Neroli oil represents a top note, citronellol and geraniol are body notes. The solvent is ethanol diluted with water to the required concentration. Let us consider this mixture as a base perfume to which musk ketone (4-tert-butyl-2,6-dimethyl-3,5-dinitroacetophenone) is added as an end note or fixative. 

A method with LOQ at ppt levels was developed based on LLE followed by GC-AFID for the determination of trace concentrations of nitrobenzene, l-chloro-2-nitrobenzene and synthetic fragrances such as musk xylene (223) and musk ketone (224). The method was applied to study the distribution of these compounds in environmental samples of North Sea waters460. GC with atomic emission detection (AED) has been successfully applied to the determination of nitro musks in human adipose tissues, at ppb concentration levels. A clean-up procedure for nonpolar substances and element-specific detection with AED enabled for the first time target screening analysis for lipophilic nitro aromatic compounds. The lack of sensitivity of AED was compensated by higher concentrations of the extracts... 

European Commission (2005b) Summary risk assessment report (4 -tert-butyl-2 ,6 -dimethyl-3 ,5 -dinitroacetophenone) musk ketone, http //esis.jrc.ec.europa.eu... 

Lehman-McKeeman ED, Caudill D, Vassallo JD, Pearce RE, Madan A, Parkinson A (1999) Effects of musk xylene and musk ketone on rat hepatic cytochrome P450 enzymes. Toxicol Lett 111 105-115... 

Hawkins DR, Elsom LF, Kirkpatrick D, Ford RA, Api AM (2002) Dermal absorption and disposition of musk ambrette, musk ketone and musk xylene in human subjects. Toxicol Lett 131 147-151... 

Location Population Served Type of Environment Galaxohde (HHCB) Tonalide (AHTN) Celestohde (ADBI) Phentolide (AHMI) Cashmerun (DPMI) Traseolide (ATTI) Musk Xylene (MX) Musk Ketone (MK)... 

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... 

Similarity between odors arises because dissimilar substances or mixtures of compounds may interact with receptors to create similar sensory impressions in the sensory centers of the brain. The group of musk fragrances (comprising macro-cyclic ketones and esters as well as aromatic nitro compounds and polycyclic aromatics) are, for example, compounds with similar odors but totally different structures [5, 6]. Small changes in structure (e.g., the introduction of one or more double bonds in aliphatic alcohols or aldehydes) may, however, alter a sensory... 

Ketones are most widely represented and include cyclopentanone derivatives, such as the jasmin fragrance substances, and cyclic ketones with 15-17-membered carbon rings, such as muscone and civetone, which are constituents of the extremely expensive animal products, musk and civet. Cyclopentadecanone, a natural musk fragrance, and the unsaturated 5-cyclohexadecen-l-one, which has not yet been found in nature, have odor characteristics similar to those of muscone and civetone and are more easily synthesized. They are, therefore, often used as substitutes. 

The aromatic ketones that occur or are used as fragrance and flavor materials are predominantly aryl methyl ketones, which include acetophenones and /3-naphthyl methyl ketone. Several acetylpolymethylindanes and -tetralins are commercially important as musk fragrances. 

The indane ketone is a musk fragrance that is stable to light and in soap. It is used in perfumes and cosmetics for its fixative properties as well as its fragrance. FCT 1975 (13) p.693. 

---