Synthetic musk

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Synthetic musks are a class of synthetic aroma compounds to emulate the scent of deer musk and other animal musks (castoreum and civet). Synthetic musks have a clean, smooth and sweet scent lacking the fecal notes of animal musks. They are used as flavorings and fixatives in cosmetics, detergents, perfumes and foods, supplying the base note of many perfume formulas. Most musk fragrance used in perfumery today is synthetic.

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Synthetic musks in a narrower sense are chemicals modeled after the main odorants in animal musk: muscone in deer musk, and civetone in civet. Muscone and civetone are macrocyclic ketones. Other structurally different but functionally similar compounds also came to be known as musks.

Nitro musks

Musk xylene Musk xylene.svg
Musk xylene

An artificial musk was obtained by Albert Baur in 1888 by condensing toluene with isobutyl bromide in the presence of aluminium chloride, and nitrating the product. It was discovered accidentally as a result of Baur's attempts at producing a more effective form of trinitrotoluene (TNT). It appears that the odour depends upon the symmetry of the three nitro groups.

(Hydrated) indanes

Cashmeran (+-) Cashmeran Structural Formulae V1.svg
Cashmeran

Cyclic ethers

Ambroxide Ambrox.svg
Ambroxide
Galaxolide Galaxolide.svg
Galaxolide

The creation of this class of musks was largely prompted through the need for eliminating the nitro functional group from nitro-musks due to their photochemical reactivity and their instability in alkaline media. This was shown to be possible through the discovery of ambroxide, a non-nitro aromatic musk, which promoted research in the development of nitro-free musks. This led to the eventual discovery of phantolide, so named due to its commercialization by Givaudan without initial knowledge of its chemical structure (elucidated 4 years later). While poorer in smell strength, the performance and stability of this compound class in harsh detergents led to its common use, which spurred further development of other polycyclic musks including Galaxolide. [1]

Macrocyclic ketones

Muscone Muscone horizontal.svg
Muscone

A class of artificial musk consisting of a single ring composed of more than 6 carbons (often 10–15). Of all artificial musks, these most resemble the primary odoriferous compound from Tonkin musk in its "large ringed" structure. While the macrocyclic musks extracted from plants consists of large ringed lactones, all animal derived macrocyclic musks are ketones. [1]

Although muscone, the primary macrocyclic compound of musk was long known, it was only in 1926 that Leopold Ruzicka was able to synthesize this compound in very small quantities. Despite this discovery and the discovery of other pathways for synthesis of macrocyclic musks, compounds of this class were not commercially produced and commonly utilized until the late 1990s due to difficulties in their synthesis and consequently higher price. [2]

Aliphatic lactones

Polycyclic lactones

Sclareolide Sclareolide structure.png
Sclareolide

Macrocyclic lactones

Cyclopentadecanolide Pentadecanolactone.svg
Cyclopentadecanolide

Hydronaphthalenes

Iso E Super Iso E Super structure.svg
Iso E Super

Alicyclic musks

Helvetolide D-Helvetolide.svg
Helvetolide

Alicyclic musks, otherwise known as cycloalkyl ester or linear musks, are a relatively novel class of musk compounds. The first compound of this class was introduced 1975 with Cyclomusk, though similar structures were noted earlier in citronellyl oxalate and Rosamusk. [3] Alicyclic musks are dramatically different in structure than previous musks (aromatic, polycyclic, macrocyclic) in that they are modified alkyl esters. [4] Although they were discovered prior to 1980, it was only in 1990 with the discovery and introduction of Helvetolide at Firmenich that a compound of this class was produced at a commercial scale. [3] Romandolide, a more ambrette and less fruity alicyclic musk compared to Helvetolide, was introduced ten years later. [4]

Environmental and health issues

Synthetic musks are lipophilic compounds and tend to deposit and persist in fat tissues. [5] Nitromusks and polycyclic musks – having been used for 100 years – have low biodegradability and accumulate in the environment. Chemicals such as musk ketone and diethyl phthalate, which are found in perfume formulas, can lead to allergic reactions, hormone disruption and it has been suggested that exposure to perfumes and/or synthetic fragrances may be linked to the development of autism spectrum disorder. [6]

Related Research Articles

<span class="mw-page-title-main">Ester</span> Compound derived from an acid

In chemistry, an ester is a compound derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.

Perfume is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. Perfumes can be defined as substances that emit and diffuse a pleasant and fragrant odor. They consist of manmade mixtures of aromatic chemicals and essential oils. The 1939 Nobel Laureate for Chemistry, Leopold Ružička stated in 1945 that "right from the earliest days of scientific chemistry up to the present time, perfumes have substantially contributed to the development of organic chemistry as regards methods, systematic classification, and theory."

<span class="mw-page-title-main">Musk</span> Class of aromatic substances used in perfumes

Musk is a class of aromatic substances commonly used as base notes in perfumery. They include glandular secretions from animals such as the musk deer, numerous plants emitting similar fragrances, and artificial substances with similar odors. Musk was a name originally given to a substance with a strong odor obtained from a gland of the musk deer. The substance has been used as a popular perfume fixative since ancient times and is one of the most expensive animal products in the world. The name originates from the Late Greek μόσχος 'moskhos', from Persian mushk and Sanskrit मुष्क muṣka derived from Proto-Indo-European noun múh₂s meaning "mouse". The deer gland was thought to resemble a scrotum. It is applied to various plants and animals of similar smell and has come to encompass a wide variety of aromatic substances with similar odors, despite their often differing chemical structures and molecular shapes.

Lactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure, or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring.

<span class="mw-page-title-main">Leopold Ružička</span> Croatian-Swiss chemist (1887–1976)

Leopold Ružička was a Croatian-Swiss scientist and joint winner of the 1939 Nobel Prize in Chemistry "for his work on polymethylenes and higher terpenes" "including the first chemical synthesis of male sex hormones." He worked most of his life in Switzerland, and received eight doctorates honoris causa in science, medicine, and law; seven prizes and medals; and twenty-four honorary memberships in chemical, biochemical, and other scientific societies.

<span class="mw-page-title-main">Karl Ziegler</span> German chemist (1898–1973)

Karl Waldemar Ziegler was a German chemist who won the Nobel Prize in Chemistry in 1963, with Giulio Natta, for work on polymers. The Nobel Committee recognized his "excellent work on organometallic compounds [which]...led to new polymerization reactions and ... paved the way for new and highly useful industrial processes". He is also known for his work involving free-radicals, many-membered rings, and organometallic compounds, as well as the development of Ziegler–Natta catalyst. One of many awards Ziegler received was the Werner von Siemens Ring in 1960 jointly with Otto Bayer and Walter Reppe, for expanding the scientific knowledge of and the technical development of new synthetic materials.

Firmenich SA was a Swiss company in the fragrance and flavor business. The company has created perfumes for over 125 years and produced a number of well-known flavors. Founded in 1895, it merged in May 2023 with the Dutch company DSM to form dsm-firmenich.

<span class="mw-page-title-main">Civetone</span> Chemical compound

Civetone is a macrocyclic ketone and the main odorous constituent of civet oil. It is a pheromone sourced from the African civet. It has a strong musky odor that becomes pleasant at extreme dilutions. Civetone is closely related to muscone, the principal odoriferous compound found in musk; the structure of both compounds was elucidated by Leopold Ružička. Today, civetone can be synthesized from precursor chemicals found in palm oil.

A fixative is a substance used to equalize the vapor pressures, and thus the volatilities, of the raw materials in a perfume oil, and to increase the perfume's odour tenacity.

<span class="mw-page-title-main">Muscone</span> Chemical compound

Muscone is a macrocyclic ketone, an organic compound that is the primary contributor to the odor of musk. Natural muscone is obtained from musk, a glandular secretion of the musk deer, which has been used in perfumery and medicine for thousands of years. Since obtaining natural musk requires killing the endangered animal, nearly all muscone used in perfumery and for scenting consumer products today is synthetic. It has the characteristic smell of being "musky".

<span class="mw-page-title-main">Perfumer</span> Expert on creating perfume compositions

A perfumer is an expert on creating perfume compositions, sometimes referred to affectionately as a nose due to their fine sense of smell and skill in producing olfactory compositions. The perfumer is effectively an artist who is trained in depth on the concepts of fragrance aesthetics and who is capable of conveying abstract concepts and moods with compositions. At the most rudimentary level, a perfumer must have a keen knowledge of a large variety of fragrance ingredients and their smells, and be able to distinguish each one alone or in combination with others. They must also know how each reveals itself over time. The job of the perfumer is very similar to that of flavourists, who compose smells and flavourants for commercial food products.

<span class="mw-page-title-main">Cyclic compound</span> Molecule with a ring of bonded atoms

A cyclic compound is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon, none of the atoms are carbon, or where both carbon and non-carbon atoms are present. Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic or non-aromatic; in the latter case, they may vary from being fully saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of small size numbers in the many billions.

<span class="mw-page-title-main">Calone</span> Chemical compound

Calone or methylbenzodioxepinone, trade-named Calone 1951, also known in the industry as "watermelon ketone", was discovered by Pfizer in 1966. It is used to give the olfactory impression of a fresh seashore through the marine and ozone nuances. Calone is similar in structure to brown algae pheromones like ectocarpene and is also distantly related in structure to the benzodiazepine class of sedatives.

Headspace technology is a technique developed in the 1980s to elucidate the odor compounds present in the air surrounding various objects. Usually the objects of interest are odoriferous objects such as plants, flowers and foods. Similar techniques are also used to analyze the interesting scents of locations and environments such as tea shops and saw mills. After the data is analyzed, the scents can then be recreated by a perfumer.

<span class="mw-page-title-main">Philip Kraft</span> German chemist (born 1969)

Philip Kraft is a German organic chemist. Since 1996 he has been employed by Givaudan, a leading Flavor and Fragrance company, where he designs captive odorants for use in perfumes. He has lectured at the University of Bern, the University of Zurich, and the ETH Zurich.

A captive odorant, or short captive, is an odorant or aroma chemical retained by the originating manufacturer for exclusive use in their own perfumes to protect them from imitation.

<span class="mw-page-title-main">Cyclopentadecanolide</span> Chemical compound

Cyclopentadecanolide is a natural macrolide lactone and a synthetic musk.

<span class="mw-page-title-main">Cashmeran</span> Chemical compound

Cashmeran is a chemical compound used in fragrances.

<span class="mw-page-title-main">Cyclohexadecanone</span> Chemical compound

Cyclohexadecanone is an organic compound with the formula (CH2)15CO. It is a cyclic ketone, which is a minor component of the musk scent of the civet. Several related derivatives are also important in the fragrance industry, especially those with alkene group in the backbone such as civetone, muscone, and 5-cyclohexadecenone (velvione). It is synthesized from cyclododecanone.

<span class="mw-page-title-main">5-Cyclohexadecenone</span> Chemical compound

5-Cyclohexadecenone is a macrocyclic synthetic musk with the chemical formula C16H28O. It is an unsaturated analog of cyclohexadecanone. It is also similar in chemical structure to the natural musk scents civetone and muscone.

References

  1. 1 2 Philip Kraft (2004). "Chapter 7. Aroma Chemicals IV: Musks". In Rowe, David J. (ed.). Chemistry and Technology of Flavours and Fragrances. Blackwell. ISBN   0-8493-2372-X.
  2. Charles (Ed.), Sell; Charles Sell (2005). "Chapter 4. Ingredients for the Modern Perfumery Industry". The Chemistry of Fragrances (2nd ed.). Royal Society of Chemistry Publishing. ISBN   978-0-85404-824-3.
  3. 1 2 Kraft, Philip (2004). "'Brain Aided' Musk Design". Chemistry & Biodiversity. 1 (12): 1957–1974. doi:10.1002/cbdv.200490150. PMID   17191832. S2CID   21645119.
  4. 1 2 Eh, Marcus (2004). "New Alicyclic Musks: The Fourth Generation of Musk Odorants". Chemistry & Biodiversity. 1 (12): 1975–1984. doi:10.1002/cbdv.200490151. PMID   17191833. S2CID   31505456.
  5. Tumová, Jitka; Šauer, Pavel; Golovko, Oksana; Koba Ucun, Olga; Grabic, Roman; Máchová, Jana; Kocour Kroupová, Hana (2019). "Effect of polycyclic musk compounds on aquatic organisms: A critical literature review supplemented by own data". Science of the Total Environment. 651 (2): 2235–2246. Bibcode:2019ScTEn.651.2235T. doi:10.1016/j.scitotenv.2018.10.028. S2CID   53019067.
  6. Sealey, L.A.; Hughes, B.W.; Sriskanda, A.N.; Guest, J.R.; Gibson, A.D.; Johnson-Williams, L.; Pace, D.G.; Bagasra, O. (2016). "Environmental factors in the development of autism spectrum disorders". Environment International. 88: 288–298. doi:10.1016/j.envint.2015.12.021. PMID   26826339.