Undecylenic acid is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

with the formula CH₂=CH(CH₂)₈CO₂H. It is an unsaturated

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, f ...

. It is a colorless oil. Undecylenic acid is mainly used for the production of Nylon-11 and in the treatment of fungal infections of the skin, but it is also a precursor in the manufacture of many

pharmaceuticals A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and re ...

, personal hygiene products,

cosmetics Cosmetics are constituted mixtures of chemical compounds derived from either natural sources, or synthetically created ones. Cosmetics have various purposes. Those designed for personal care and skin care can be used to cleanse or protec ...

, and perfumes.

Salts In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively c ...

and

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

s of undecylenic acid are known as undecylenates.

Preparation

Undecylenic acid is prepared by

pyrolysis The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements '' ...

ricinoleic acid Ricinoleic acid, formally called 12-hydroxy-9-''cis''-octadecenoic acid is a fatty acid. It is an unsaturated omega-9 fatty acid and a hydroxy acid. It is a major component of the seed oil obtained from mature castor plant (''Ricinus communis'' ...

, which is derived from

castor oil Castor oil is a vegetable oil pressed from castor beans. It is a colourless or pale yellow liquid with a distinct taste and odor. Its boiling point is and its density is 0.961 g/cm3. It includes a mixture of triglycerides in which about ...

. Specifically, the

methyl In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in ...

of ricinoleic acid is

cracked Cracked may refer to: Television * ''Cracked'' (British TV series), a 2008 British comedy-drama television series that aired on STV * ''Cracked'' (Canadian TV series), a 2013 Canadian crime drama series that aired on CBC * "Cracked", a Season 8 ( ...

to yield both undecylenic acid and

heptanal Heptanal or heptanaldehyde is an alkyl aldehyde. It is a colourless liquid with a strong fruity odor, which is used as precursor to components in perfumes and lubricants. Production The formation of heptanal in the fractional distillation of cas ...

. The process is conducted at 500–600 °C in the presence of steam.David J. Anneken, Sabine Both, Ralf Christoph, Georg Fieg, Udo Steinberner, Alfred Westfechtel "Fatty Acids" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2006, Wiley-VCH, Weinheim. The methyl ester is then

hydrolyzed Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

. :

General commercial uses

Undecylenic acid is converted to

11-aminoundecanoic acid 11-Aminoundecanoic acid is an organic compound with the formula H2N(CH2)10CO2H. This white solid is classified as an amine and a fatty acid. 11-Aminoundecanoic acid is a precursor to Nylon-11. Production As practiced by Arkema, 11-aminound ...

on an industrial scale. This aminocarboxylic acid is the precursor to Nylon-11. Undecylenic acid is reduced to undecylene aldehyde, which is valued in perfumery. The acid is first converted to the

acid chloride In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group . Their formula is usually written , where R is a side chain. They are reactive derivatives of carboxylic acids (). A specific example o ...

, which allows selective reduction.

Medical uses

Undecylenic acid is an active ingredient in medications for skin infections, and to relieve itching, burning, and irritation associated with skin problems. For example, it is used against fungal skin infections, such as

athlete's foot Athlete's foot, known medically as ''tinea pedis'', is a common skin infection of the feet caused by a fungus. Signs and symptoms often include itching, scaling, cracking and redness. In rare cases the skin may blister. Athlete's foot fungus ...

ringworm Dermatophytosis, also known as ringworm, is a fungal infection of the skin. Typically it results in a red, itchy, scaly, circular rash. Hair loss may occur in the area affected. Symptoms begin four to fourteen days after exposure. Multiple ar ...

tinea cruris Tinea cruris, also known as jock itch, is a common type of contagious, superficial fungal infection of the groin and buttocks region, which occurs predominantly but not exclusively in men and in hot-humid climates. Typically, over the upper inner ...

, or other generalized infections by ''

Candida albicans ''Candida albicans'' is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is usu ...

''. When used for

, it can result in extreme burning. In some case studies of tinea versicolor, pain and burning result from fungicide application. In a review of placebo-controlled trials, undecenoic acid was deemed efficacious, alongside prescription azoles (e.g.,

clotrimazole Clotrimazole, sold under the brand name Lotrimin, among others, is an antifungal medication. It is used to treat vaginal yeast infections, oral thrush, diaper rash, tinea versicolor, and types of ringworm including athlete's foot and jock ...

) and allylamines (e.g., terbinafine). Undecylenic acid is also a precursor to antidandruff shampoos and antimicrobial powders. In terms of the mechanism underlying its antifungal effects against ''Candida albicans'', undecylenic acid inhibits morphogenesis. In a study on denture liners, undecylenic acid in the liners was found to inhibit conversion of yeast to the hyphal form (which are associated with active infection), via inhibition of fatty acid biosynthesis. The mechanism of action and effectiveness in fatty acid-type antifungals is dependent on the number of carbon atoms in the chain, with efficacy increasing with the number of atoms in the chain.

U.S. FDA approval

Undecylenic acid is approved by the U.S. FDA for topical route and is listed in the Code of Federal Regulations.Publisher FDA
CFR Title 21, Volume 5, Chapter 1, Subchapter D, Part 333, Subpart C, Sec. (§333.210)

Research uses

Undecylenic acid has been used as a linking molecule, because it is a

bifunctional compound In organic chemistry, when a single organic molecule has two different functional groups, it is called a bifunctional molecule . A bifunctional molecule has the properties of two different types of functional groups, such as an alcohol (), amide ( ...

. Specifically it is an α,ω- (terminally functionalized) bifunctional agent. For instance, the title compound has been used to prepare silicon-based biosensors, linking silicon transducer surfaces to the terminal double bond of undecylenic acid (forming an Si-C bond), leaving the

carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxyli ...

groups available for

conjugation Conjugation or conjugate may refer to: Linguistics *Grammatical conjugation, the modification of a verb from its basic form * Emotive conjugation or Russell's conjugation, the use of loaded language Mathematics *Complex conjugation, the change ...

of biomolecules (e.g., proteins).

References

{{Antifungals McLain N, Ascanio R, Baker C, et al. Undecylenic acid inhibits morphogenesis of Candida albicans. Antimicrob Agents Chemother 2000;44:2873-2875 Alkenoic acids Antifungals Fatty acids