Coumarin () or 2''H''-chromen-2-one is an aromatic organic

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one ele ...

with formula . Its molecule can be described as a

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen ato ...

molecule with two adjacent

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

atoms replaced by a lactone-like chain , forming a second six-membered

heterocycle A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and ...

that shares two

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes ...

s with the benzene ring. It can be placed in the benzopyrone chemical class and considered as a

lactone 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. Lactones are formed by intramolecular esterification of the co ...

. Coumarin is a colorless crystalline solid with a sweet

odor An odor (American English) or odour (Commonwealth English; see spelling differences) is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive via their sense ...

resembling the scent of

vanilla Vanilla is a spice derived from orchids of the genus ''Vanilla (genus), Vanilla'', primarily obtained from pods of the Mexican species, flat-leaved vanilla (''Vanilla planifolia, V. planifolia''). Pollination is required to make the p ...

and a bitter taste. It is found in many plants, where it may serve as a chemical defense against predators. By inhibiting synthesis of

vitamin K Vitamin K refers to structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-synthesis modification of certain proteins that are required for blood coagulat ...

, a related compound is used as the

prescription drug A prescription drug (also prescription medication or prescription medicine) is a pharmaceutical drug that legally requires a medical prescription to be dispensed. In contrast, over-the-counter drugs can be obtained without a prescription. The rea ...

warfarin Warfarin, sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pulmonary embolism, and to prevent ...

– an

anticoagulant Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where t ...

– to inhibit formation of

blood clot A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of cr ...

deep vein thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and e ...

, and

pulmonary embolism Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathing ...

Etymology

Coumarin is derived from ''coumarou'', the French word for the tonka bean. The word ''tonka'' for the

tonka bean ''Dipteryx odorata'' (commonly known as "cumaru", "kumaru", or "Brazilian teak") is a species of flowering tree in the pea family, Fabaceae. The tree is native to Central America and northern South America and is semi-deciduous. Its seeds a ...

is taken from the Galibi (Carib) tongue spoken by natives of

French Guiana French Guiana ( or ; french: link=no, Guyane ; gcr, label=French Guianese Creole, Lagwiyann ) is an overseas departments and regions of France, overseas department/region and single territorial collectivity of France on the northern Atlantic ...

(one source for the plant); it also appears in

Old Tupi Old Tupi, Ancient Tupi or Classical Tupi (also spelled as Tupí) is an extinct Tupian language which was spoken by the aboriginal Tupi people of Brazil, mostly those who inhabited coastal regions in South and Southeast Brazil. It belongs to the ...

, another language of the same region, as the name of the tree. The old genus name, '' Coumarouna'', was formed from another Tupi name for tree, ''kumarú''.

History

Coumarin was first isolated from tonka beans in 1820 by A. Vogel of Munich, who initially mistook it for

benzoic acid Benzoic acid is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, w ...

. Also in 1820, Nicholas Jean Baptiste Gaston Guibourt (1790–1867) of France independently isolated coumarin, but he realized that it was not benzoic acid. In a subsequent essay he presented to the pharmacy section of the Académie Royale de Médecine, Guibourt named the new substance ''coumarine''. In 1835, the French pharmacist A. Guillemette proved that Vogel and Guibourt had isolated the same substance. Coumarin was first synthesized in 1868 by the English chemist

William Henry Perkin Sir William Henry Perkin (12 March 1838 – 14 July 1907) was a British chemist and entrepreneur best known for his serendipitous discovery of the first commercial synthetic organic dye, mauveine, made from aniline. Though he failed in trying ...

. Coumarin has been an integral part of the fougère genre of perfume since it was first used in Houbigant's Fougère Royale in 1882.

Synthesis

Coumarin can be prepared by a number of

name reaction A name reaction is a chemical reaction named after its discoverers or developers. Among the tens of thousands of organic reactions that are known, hundreds of such reactions are well-known enough to be named after people. Well-known examples include ...

s, with the Perkin reaction between

salicylaldehyde Salicylic aldehyde (2-hydroxybenzaldehyde) is the organic compound with the formula (C7 H6 O2) C6H4CHO-2-OH. Along with 3-hydroxybenzaldehyde and 4-hydroxybenzaldehyde, it is one of the three isomers of hydroxybenzaldehyde. This colorless oi ...

and

acetic anhydride Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH3CO)2O. Commonly abbreviated Ac2O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis. It is a c ...

being a popular example. The Pechmann condensation provides another route to coumarin and its derivatives, as does the Kostanecki acylation, which can also be used to produce chromones.

Biosynthesis

From lactonization of ''ortho''-hydroxylated ''cis''-

hydroxycinnamic acid Hydroxycinnamic acids (hydroxycinnamates) are a class of aromatic acids or phenylpropanoids having a C6–C3 skeleton. These compounds are hydroxy derivatives of cinnamic acid. In the category of phytochemicals that can be found in food, there ...

Natural occurrence

Coumarin is found naturally in many

plant Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all curr ...

s. Freshly ground plant parts contain higher amount of desired and undesired phytochemicals than powder. Also, whole plant parts are harder to counterfeit; for example, one study showed that authentic Ceylon cinnamon bark contained 0.012 to 0.143 mg/g coumarin, but samples purchased at markets contained up to 3.462 mg/g, possibly because those were mixed with other cinnamon varieties. * Vanilla grass ('' Anthoxanthum odoratum'') * Sweet woodruff (''

Galium odoratum ''Galium odoratum'', the sweet woodruff or sweetscented bedstraw, is a flowering perennial plant in the family Rubiaceae, native to much of Europe from Spain and Ireland to Russia, as well as Western Siberia, Turkey, Iran, the Caucasus, China ...

'') * Sweet grass ('' Hierochloe odorata'') * Sweet-clover (genus ''

Melilotus ''Melilotus'', known as melilot, sweet clover, and kumoniga (from the Cumans),Bulgarian Folk Customs, Mercia MacDermott, pg 27 is a genus in the family Fabaceae (the same family that also includes the ''Trifolium'' clovers). Members are known ...

'') *

Tonka bean ''Dipteryx odorata'' (commonly known as "cumaru", "kumaru", or "Brazilian teak") is a species of flowering tree in the pea family, Fabaceae. The tree is native to Central America and northern South America and is semi-deciduous. Its seeds a ...

(''Dipteryx odorata'') *

Cinnamon Cinnamon is a spice obtained from the inner bark of several tree species from the genus '' Cinnamomum''. Cinnamon is used mainly as an aromatic condiment and flavouring additive in a wide variety of cuisines, sweet and savoury dishes, brea ...

; a 2013 study showed different varieties containing different levels of coumarin: ** Ceylon cinnamon or true cinnamon (''

Cinnamomum verum ''Cinnamomum verum'', called true cinnamon tree or Ceylon cinnamon tree, is a small evergreen tree belonging to the family Lauraceae, native to Sri Lanka. The inner bark of several other ''Cinnamomum'' species are also used to make cinnamon, but ...

''): 0.005 to 0.090 mg/g ** Chinese cinnamon or Chinese cassia ('' C. cassia''): 0.085 to 0.310 mg/g ** Indonesian cinnamon or Padang cassia ('' C. burmannii''): 2.14 to 9.30 mg/g **

Saigon cinnamon Saigon cinnamon (''Cinnamomum loureiroi'', also known as Vietnamese cinnamon or Vietnamese cassia and ''quế trà my'', ''quế thanh'', or " quế trà bồng" in Vietnam) is an evergreen tree indigenous to mainland Southeast Asia. Saigon cinna ...

or Vietnamese cassia (''C. loureiroi''): 1.06 to 6.97 mg/g * Deertongue (''

Carphephorus odoratissimus ''Carphephorus odoratissimus'' (syn. ''Trilisa odoratissima''), common name vanillaleaf, is a species of North American plants in the family Asteraceae. This species is native to the southeastern United States, including the states of Georgia, No ...

''), * Tilo ('' Justicia pectoralis''), * Mullein (genus ''

Verbascum ''Verbascum'' is a genus of over 450 species of flowering plants, common name mullein (), in the figwort family Scrophulariaceae. They are native to Europe and Asia, with the highest species diversity in the Mediterranean. Mullein or "mullein le ...

'') * Many

cherry blossom A cherry blossom, also known as Japanese cherry or sakura, is a flower of many trees of genus ''Prunus'' or ''Prunus'' subg. ''Cerasus''. They are common species in East Asia, including China, Korea and especially in Japan. They generally ...

tree varieties (of the genus ''

Prunus ''Prunus'' is a genus of trees and shrubs, which includes (among many others) the fruits plums, cherries, peaches, nectarines, apricots, and almonds. Native to the North American temperate regions, the neotropics of South America, and the p ...

''). * Related compounds are found in some but not all specimens of genus ''Glycyrrhiza'', from which the root and flavour