3-Mercapto-3-methylbutan-1-ol

Last updated
3-Mercapto-3-methylbutan-1-ol [1]
3-mercapto-3-methylbutan-1-ol.svg
Names
Preferred IUPAC name
3-Methyl-3-sulfanylbutan-1-ol
Other names
3-Mercapto-3-methylbutan-1-ol (no longer recommended [2] )
Identifiers
3D model (JSmol)
AbbreviationsMMB
ChEBI
ChemSpider
ECHA InfoCard 100.157.543 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 629-355-5
PubChem CID
UNII
  • InChI=1S/C5H12OS/c1-5(2,7)3-4-6/h6-7H,3-4H2,1-2H3 Yes check.svgY
    Key: GBCGIJAYTBMFHI-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C5H12OS/c1-5(2,7)3-4-6/h6-7H,3-4H2,1-2H3
    Key: GBCGIJAYTBMFHI-UHFFFAOYAN
  • CC(C)(CCO)S
  • OCCC(S)(C)C
Properties
C5H12OS
Molar mass 120.21 g/mol
Density 0.985 g/mL at 20 °C
Hazards
GHS labelling:
GHS-pictogram-acid.svg GHS-pictogram-exclam.svg
Danger
H302, H315, H318, H319, H335
P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P310, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

3-Mercapto-3-methylbutan-1-ol, also known as MMB, is a common odorant found in food and cat urine. The aromas ascribed to MMB include catty, [3] roasty, broth-like, meaty, and savory, [4] or similar to cooked leeks. [5]

Contents

MMB is an organosulfur compound with the formula C5H12OS. Its structure consists of isopentane with a primary alcohol group and a tertiary thiol group attached to a β-carbon relative to the alcohol. MMB is found in the urine of leopards and domestic cats, and is considered an important semiochemical in male scent-marking. [6] MMB is also a common odorant in food, including coffee, [7] passionfruit juice, [8] and Sauvignon Blanc wines. [5] As a tertiary thiol, MMB is structurally similar to other "catty" thiols, including 3-mercapto-3-methyl-2-pentanone, 4-mercapto-4-methyl-2-pentanone, 8-mercapto-p-menthan-3-one, and 2-mercapto-2-methylbutane. [4]

Synthesis

The compound can be produced through many methods. The most well-known reaction sequence begins with ethyl acetate, which is activated with lithium bis(trimethylsilyl)amide at the α-position and coupled with acetone to form ethyl 3-hydroxy-3-methylbutyrate. The 3-hydroxy-3-methylbutyrate is then brominated, treated with thiourea, and hydrolyzed to form 3-mercapto-3-methyl-butyric acid. The compound is then reduced with lithium aluminum hydride to form 3-mercapto-3-methylbutanol. [7]

MMB synthesis from EtOAc.jpg

Since MMB is most often synthesized for use as a standard in isotope dilution assays, [9] most instances of MMB synthesis in chemical literature involve acetone-d6 to form [2H6]-3-mercapto-3-methylbutanol.

MMB in Food and Drink

Besides felinine, MMB was first identified in the plant kingdom in Vitis vinifera L. cv., Sauvignon Blanc. [10] [11]

MMB is known to be a key odorant in sauvignon blanc grapes. Sauvignon blanc vlasotince vineyards.jpg
MMB is known to be a key odorant in sauvignon blanc grapes.

3-mercapto-3-methylbutan-1-ol have been known to be used commercially as aromas for certain foods such as Sauvignon Blanc wine and coffee. MMB has also been identified in passion fruit juice along with its acetate. [12]

MMB recently discovered to occur naturally in Passion fruit. Passionfruit.jpg
MMB recently discovered to occur naturally in Passion fruit.
MMB is also an odorant in coffee. Coffeebeans.jpg
MMB is also an odorant in coffee.

The synthesis of the MMB was formed by the action of the bacterial extract on CESFPs of passion fruit juice. One study looked at the influence of human whole saliva on odor-active thiols, specifically that of salivary enzymes breaking down MMB. [13] The degradation of MMB is thought to be induced by enzymatic activity, and it is much faster than other volatile thiols. [14] Another study found that the perception threshold of 3-mercapto-3-methylbutan-1-ol is 1500 ng/L. [15] This study found that MMB had a "catty" odor, had an orthonasal odor threshold of 2 μg/L in water, and was found in concentrations from 150-1500 μg/kg in coffee.

The synthesis of MMB in wine is brought on by the fermentation process. The pathway of formation for the aromatic precursors involves four important steps: enzymatic oxidation, metabolic processing of unsaturated fatty acids, cysteinlated or glutathionylated conjugation to aldehydes, and a β-lyase cleavage during alcoholic fermentation to release MMB. [16] In this fermentation process, strains of the certain bacterial species are characterized by an extra-cellular α-arabinofuranosidase, influencing the content of desirable varietal aromas and, in particular, Metschnikowia pulcherrima releases varietal thiols including MMB. [17] For Sauvignon Blanc, the contribution of volatile thiols to varietal aroma is quite significant as the levels in wine usually exceed the threshold of detection. Unlike most aroma compounds found in wine, volatile thiols are unique in the fact that they exist in trace amounts in the berries. [16] The intense passion fruit-type aroma of New Zealand Sauvignon Blanc wines are attributed to high concentrations of the varietal thiols. This vintner study found that aromas in wine caused by MMB diminish rapidly over just a year in its bottle. [18] [19]

Odorant in Cat Urine

MMB synthesis, within the biological system of a cat's bladder, is regulated by many different factors including cauxin, age, and sex.

Cauxin is an enzyme that acts as a nonspecific carboxylesterase abundant in feline urine which converts 3-methylbutanol-cysteinylglycine (3MBCG) to felinine, with a side product of glycine. Upon formation, felinine gradually degrades into MMB.

3MBCG to MMB degradation.jpg

Prior to sexual maturation of cats, cauxin and MMB are not produced at significant levels since this is a testosterone-dependent, although the specific role of testosterone is not well understood. [20] With little testosterone in the body in the first three months of their life, the concentrations of cauxin and 3-methylbutanol-cysteinylglycine are too low for proper reaction conditions. Biologically, this is logical as the ability to utilize pheromones such as MMB for territory marking and finding mates is not needed during kittenhood. The testosterone dependence also explains why female cats do not have nearly as much cauxin and MMB as male cats, and in turn, why their urine does not have a species-specific odor. It also explains why urine in neutered males, who are producing a lot less testosterone than their intact counterparts, do not have.

After a cat reaches sexual maturity, a positive correlation is found with age and MMB production due to an increase in cauxin production, and release in urine with 3-methylbutanol-cysteinylglycine, allowing for the reaction to occur more frequently. This is advantageous for older cats as it allowed them to potently leave a scent trail for female cats to follow, and male cats to stay away. [21]

Studies have also demonstrated some wider predator-prey responses to MMB, cementing this molecule's role in wider ecological relationships. In wildlife, one study established that African wildcats respond to MMB dispensers, marking the territory nearby at higher rates than dispensers without, establishing they recognize the scent. Small mammals have also demonstrated a recognition of the scent, rolling around in where the wildcats have urinated in order to utilize the scent of MMB to its advantage, disguising itself in the scent of a large predator to ward off its own predators. [6] Laboratory experiments have demonstrated that MMB has a does not have an expected repelling effect on mice, who are natural prey of cats, which complicates the narrative further since it is used for a repelling effect by small mammals as a defensive mechanism. [22] Further investigation into this dynamic is needed.

MMB is found in domestic and wildcat urine Closeup of a cat with green eyes' face looking at the viewer.jpg
MMB is found in domestic and wildcat urine

See also

Related Research Articles

<span class="mw-page-title-main">Cabernet Sauvignon</span> Red-wine variety of grape

Cabernet Sauvignon is one of the world's most widely recognized red wine grape varieties. It is grown in nearly every major wine producing country among a diverse spectrum of climates from Australia and British Columbia, Canada to Lebanon's Beqaa Valley. Cabernet Sauvignon became internationally recognized through its prominence in Bordeaux wines, where it is often blended with Merlot and Cabernet Franc. From France and Spain, the grape spread across Europe and to the New World where it found new homes in places like California's Napa Valley, New Zealand's Hawke's Bay, South Africa's Stellenbosch region, Australia's Margaret River, McLaren Vale and Coonawarra regions, and Chile's Maipo Valley and Colchagua. For most of the 20th century, it was the world's most widely planted premium red wine grape until it was surpassed by Merlot in the 1990s. However, by 2015, Cabernet Sauvignon had once again become the most widely planted wine grape, with a total of 341,000 hectares (3,410 km2) under vine worldwide.

<span class="mw-page-title-main">Thiol</span> Any organic compound having a sulfanyl group (–SH)

In organic chemistry, a thiol, or thiol derivative, is any organosulfur compound of the form R−SH, where R represents an alkyl or other organic substituent. The −SH functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols, and the word is a blend of "thio-" with "alcohol".

<span class="mw-page-title-main">Sauvignon blanc</span> Green-skinned grape variety

Sauvignon blanc is a green-skinned grape variety that originates from the city of Bordeaux in France. The grape most likely gets its name from the French words sauvage ("wild") and blanc ("white") due to its early origins as an indigenous grape in South West France. It is possibly a descendant of Savagnin. Sauvignon blanc is planted in many of the world's wine regions, producing a crisp, dry, and refreshing white varietal wine. The grape is also a component of the famous dessert wines from Sauternes and Barsac. Sauvignon blanc is widely cultivated in France, Chile, Romania, Canada, Australia, New Zealand, South Africa, Bulgaria, the states of Oregon, Washington, and California in the US. Some New World Sauvignon blancs, particularly from California, may also be called "Fumé Blanc", a marketing term coined by Robert Mondavi in reference to Pouilly-Fumé.

<span class="mw-page-title-main">Aroma compound</span> Chemical compound that has a smell or odor

An aroma compound, also known as an odorant, aroma, fragrance or flavoring, is a chemical compound that has a smell or odor. For an individual chemical or class of chemical compounds to impart a smell or fragrance, it must be sufficiently volatile for transmission via the air to the olfactory system in the upper part of the nose. As examples, various fragrant fruits have diverse aroma compounds, particularly strawberries which are commercially cultivated to have appealing aromas, and contain several hundred aroma compounds.

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

Sotolon is a lactone and an extremely powerful aroma compound, with the typical smell of fenugreek or curry at high concentrations and maple syrup, caramel, or burnt sugar at lower concentrations. Sotolon is the major aroma and flavor component of fenugreek seed and lovage, and is one of several aromatic and flavor components of artificial maple syrup. It is also present in molasses, aged rum, aged sake and white wine, flor sherry, roast tobacco, and dried fruiting bodies of the mushroom Lactarius helvus. Sotolon can pass through the body relatively unchanged, and consumption of foods high in sotolon, such as fenugreek, can impart a maple syrup aroma to one's sweat and urine. In some individuals with the genetic disorder maple syrup urine disease, it is spontaneously produced in their bodies and excreted in their urine, leading to the disease's characteristic smell.

Grapefruit mercaptan is a natural organic compound found in grapefruit. It is a monoterpenoid that contains a thiol functional group. Structurally a hydroxy group of terpineol is replaced by the thiol in grapefruit mercaptan, so it also called thioterpineol. Volatile thiols typically have very strong, often unpleasant odors that can be detected by humans in very low concentrations. Grapefruit mercaptan has a very potent, but not unpleasant, odor, and it is the chemical constituent primarily responsible for the aroma of grapefruit. This characteristic aroma is a property of only the R enantiomer.

<span class="mw-page-title-main">Cat communication</span> Feline means of sending or receiving information

Cats need to communicate for a variety of reasons, including to show happiness, to express anger, to solicit attention, and to observe potential prey; cats collaborate, play, and share resources with each other. When they communicate with humans, they do so to get what they need or want, such as food, water, attention, or play.

The Flavour and Fragrance Journal is a bimonthly peer-reviewed scientific journal published since 1985 by John Wiley & Sons. It publishes original research articles, reviews and special reports on all aspects of flavour and fragrance. The current Editor-in-Chief is Kerstin Steiner.

A cat pheromone is a chemical molecule, or compound, that is used by cats and other felids for communication. These pheromones are produced and detected specifically by the body systems of cats and evoke certain behavioural responses.

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

Felinine, also known as (R)-2-amino-3-(4-hydroxy-2-methylbutan-2-ylthio)propanoic acid, is an amino acid found in cat urine and a precursor via microbial lyase of the putative cat pheromone and thiol called 3-mercapto-3-methylbutan-1-ol (MMB). Felinine is excreted by some Felidae species, including bobcats, Chinese desert cats, the kodkod, and domestic cats.

Cauxin is a carboxylesterase that is excreted in large amounts in cat urine. There is also evidence that it can serve as a peptide hydrolase in the production of cat pheromone precursors. Cauxin has a mass of 70 kilodaltons and is composed of 545 amino acids. The protein can also exist as a multimeric protein complex connected by disulfide bonds with a mass of 300-350 kilodaltons. This is its primary form in non-reducing conditions. The proximal tubules of epithelial cells in the kidney express cauxin. This protein is secreted into the urine from the renal tubular cells. The gene for the protein is also found in several other mammalian genomes in various organs. However, the only mammals that have cauxin present in urine are cats. It is also the first carboxylesterase to be found in urine.

<span class="mw-page-title-main">Wine tasting</span> Method of judging wine

Wine tasting is the sensory examination and evaluation of wine. While the practice of wine tasting is as ancient as its production, a more formalized methodology has slowly become established from the 14th century onward. Modern, professional wine tasters use a constantly evolving specialized terminology which is used to describe the range of perceived flavors, aromas and general characteristics of a wine. More informal, recreational tasting may use similar terminology, usually involving a much less analytical process for a more general, personal appreciation.

<span class="mw-page-title-main">Aroma of wine</span> Olfactory sensation of wine

The aromas of wine are more diverse than its flavours. The human tongue is limited to the primary tastes perceived by taste receptors on the tongue – sourness, bitterness, saltiness, sweetness and savouriness. The wide array of fruit, earthy, leathery, floral, herbal, mineral, and woodsy flavour present in wine are derived from aroma notes sensed by the olfactory bulb. In wine tasting, wine is sometimes smelled before taking a sip in order to identify some components of the wine that may be present. Different terms are used to describe what is being smelled. The most basic term is aroma which generally refers to a "pleasant" smell as opposed to odour which refers to an unpleasant smell or possible wine fault. The term aroma may be further distinguished from bouquet which generally refers to the smells that arise from the chemical reactions of fermentation and aging of the wine.

<span class="mw-page-title-main">Odor</span> Volatile chemical compounds perceived by the sense of smell

An odor or odour is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and many animals can perceive via their sense of smell. An odor is also called a "smell" or a "scent", which can refer to either an unpleasant or a pleasant odor.

<span class="mw-page-title-main">Sense of smell</span> Sense that detects smells

The sense of smell, or olfaction, is the special sense through which smells are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste.

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

Benzyl mercaptan is an organosulfur compound with the formula C6H5CH2SH. It is a common laboratory alkylthiol that occurs in trace amounts naturally. It is a colorless, malodorous liquid.

A key odorant is a volatile compound that is present in concentrations higher than their specific flavor threshold.

<span class="mw-page-title-main">Olmo grapes</span> Variety of grape

Olmo grapes are wine and table grape varieties produced by University of California, Davis viticulturist Dr. Harold Olmo. Over the course of his nearly 50-year career, Dr. Olmo bred a wide variety of both grapes by means of both crossing varieties from the same species or creating hybrid grapes from cultivars of different Vitis species.

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

Isopropyl methoxypyrazine (IPMP) is a methoxypyrazine, a class of chemical compounds that produce odors. The odor is rather undesirable and is produced by the Asian lady beetle or by the actinomycete Streptomyces sp. It can be detected by human taste at concentrations of as low as 2 nanograms per litre.

<span class="mw-page-title-main">4-Mercapto-4-methyl-2-pentanone</span> Chemical compound

4-Mercapto-4-methyl-2-pentanone is an aroma compound with the chemical formula C6H12OS. It has a tropical flavor. It is found in Sauvignon wines and is a potent odorant of new-world hops.

References

  1. 3-Mercapto-3-methylbutan-1-ol at Sigma-Aldrich
  2. Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 697. doi:10.1039/9781849733069-FP001. ISBN   978-0-85404-182-4. The prefixes 'mercapto' (–SH), and 'hydroseleno' or selenyl (–SeH), etc. are no longer recommended.
  3. A. Buettner (April 27, 2002). "Influence of Human Salivary Enzymes on Odorant Concentration Changes Occurring in Vivo. 1. Esters and Thiols". J. Agric. Food Chem. 50 (11): 3283–3289. doi: 10.1021/jf011586r . PMID   12009999.
  4. 1 2 M. Rychlik; P. Schieberle; W. Grosch (1998). Compilation of odor thresholds, odor qualities and retention indices of key food odorants. Instit für Lebensmittelchemie der Technischen Universität München, Garching. OCLC   59392244.
  5. 1 2 T. Tominaga; A. Furrer; R. Henry; D. Dubourdieu (December 4, 1998). "Identification of new volatile thiols in the aroma of Vitis vinifera L. var. sauvignon blanc wines". Flavour and Fragrance Journal. 13 (3): 159–162. doi:10.1002/(SICI)1099-1026(199805/06)13:3<159::AID-FFJ709>3.0.CO;2-7. Archived from the original (pdf) on December 16, 2012.
  6. 1 2 P. Apps; M. Claase; B. Yexley & J. McNutt (2017). "Interspecific responses of wild African carnivores to odour of 3-mercapto-3-methylbutanol, a component of wildcat and leopard urine". J. Ethol. 35 (2): 153–159. doi: 10.1007/s10164-016-0503-7 .
  7. 1 2 C. Masanetz; I. Blank & W. Grosch (1995). "Synthesis of [H6]-3-Mercapto-3-methylbutyl Formate to be used as an Internal Standard in Quantification Assays". Flavour Fragr. J. 10: 9–14. doi: 10.1002/ffj.2730100103 .
  8. T. Tominaga & D. Dubourdieu (June 2000). "Identification of Cysteinylated Aroma Precursors of Certain Volatile Thiols in Passion Fruit Juice". J. Agric. Food Chem. 48 (7): 2874–2876. doi: 10.1021/jf990980a . PMID   10898639.
  9. H. Tamura; A. Fujita; M. Steinhous; E. Takahisa; H. Watanabe & P. Schieberle (August 2011). "Assessment of the Aroma Impact of Major Odor-Active Thiols in Pan-Roasted White Sesame Seeds by Calculation of Odor Activity Values". J. Agric. Food Chem. 59 (18): 10211–10218. doi: 10.1021/jf202183y . PMID   21815692.
  10. Takatoshi Tominaga; Anton Furrer; Robert Henry; Denis Dubourdieu (May 30, 1997). "Identification of new volatile thiols in the aroma ofVitis vinifera L. var. sauvignon blanc wines". Flavour and Fragrance Journal. 13 (3): 159–162. doi:10.1002/(SICI)1099-1026(199805/06)13:3<159::AID-FFJ709>3.0.CO;2-7 . Retrieved May 13, 2023.
  11. Anne Krebiehl (May 27, 2020). "The Science Behind the Main Wine Aromas, Explained". Wine Enthusiast Magazine. Retrieved May 13, 2023.
  12. Takatoshi Tominaga; Denis Dubourdieu (June 7, 2000). "Identification of Cysteinylated Aroma Precursors of Certain Volatile Thiols in Passion Fruit Juice". Journal of Agricultural and Food Chemistry. ACS Publications. 48 (7): 2874–2876. doi:10.1021/jf990980a. PMID   10898639 . Retrieved May 13, 2023.
  13. Andrea Buettner (April 27, 2002). "Influence of Human Salivary Enzymes on Odorant Concentration Changes Occurring in Vivo. 1. Esters and Thiols". Journal of Agricultural and Food Chemistry. ACS Publications. 50 (11): 3283–3289. doi:10.1021/jf011586r. PMID   12009999 . Retrieved May 13, 2023.
  14. Liang Chen; Dimitra L. Capone; David W. Jeffery (July 5, 2019). "Analysis of Potent Odour-Active Volatile Thiols in Foods and Beverages with a Focus on Wine". Molecules. 24 (13): 2472. doi: 10.3390/molecules24132472 . PMC   6650874 . PMID   31284416.
  15. Takatoshi Tominaga; Anton Furrer; Robert Henry; Denis Dubourdieu (May 30, 1997). "Identification of new volatile thiols in the aroma ofVitis vinifera L. var. sauvignon blanc wines". Flavour and Fragrance Journal. 13 (3): 159–162. doi:10.1002/(SICI)1099-1026(199805/06)13:3<159::AID-FFJ709>3.0.CO;2-7 . Retrieved May 13, 2023.
  16. 1 2 Avery Heelan (2015). "Sulfur containing compounds have high aroma impact, including key varietal flavors". University of California, Davis. Retrieved May 13, 2023.
  17. Patrizia Romano; Giacomo Braschi; Gabriella Siesto; Francesca Patrignani; Rosalba Lanciotti (June 28, 2022). "Role of Yeasts on the Sensory Component of Wines". Foods. 11 (13): 1921. doi: 10.3390/foods11131921 . PMC   9265420 . PMID   35804735.
  18. Mandy Herbst-Johnstone; Laura Nicolau; Paul A. Kilmartin (July 2011). "Stability of Varietal Thiols in Commercial sauvignon blanc Wines". American Journal of Enology and Viticulture. 62 (4): 495–502. doi:10.5344/ajev.2011.11023. S2CID   85774463 . Retrieved May 13, 2023.
  19. Acuna Gonzalo; Markus Gautschi; Frank Kumli; Joachim Schmid; Janos Zsindely (October 19, 2004). "Mercapto-alkanol flavor compounds". United States Patent. Retrieved May 13, 2023.
  20. Tarttelin, M. F.; Hendriks, W. H.; Moughan, P. J. (August 1998). "Relationship between plasma testosterone and urinary felinine in the growing kitten". Physiology & Behavior. 65 (1): 83–87. doi:10.1016/s0031-9384(98)00132-2. ISSN   0031-9384. PMID   9811369. S2CID   19935926.
  21. Miyazaki, Masao; Yamashita, Tetsuro; Suzuki, Yusuke; Saito, Yoshihiro; Soeta, Satoshi; Taira, Hideharu; Suzuki, Akemi (October 2006). "A Major Urinary Protein of the Domestic Cat Regulates the Production of Felinine, a Putative Pheromone Precursor". Chemistry & Biology. 13 (10): 1071–1079. doi: 10.1016/j.chembiol.2006.08.013 . ISSN   1074-5521. PMID   17052611.
  22. Sievert, Thorbjörn; Laska, Matthias (June 2016). "Behavioral Responses of CD-1 Mice to Six Predator Odor Components". Chemical Senses. 41 (5): 399–406. doi: 10.1093/chemse/bjw015 . ISSN   1464-3553. PMID   26892309.