Names | |
---|---|
Preferred IUPAC name (2E)-3-Phenylprop-2-enoic acid | |
Systematic IUPAC name Cinnamic acid | |
Other names trans-Cinnamic acid Phenylacrylic acid [1] Cinnamylic acid 3-Phenylacrylic acid (E)-Cinnamic acid Benzenepropenoic acid Isocinnamic acid | |
Identifiers | |
3D model (JSmol) | |
3DMet | |
1905952 | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.004.908 |
EC Number |
|
3731 | |
KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
| |
| |
Properties | |
C9H8O2 | |
Molar mass | 148.161 g·mol−1 |
Appearance | White monoclinic crystals |
Odor | Honey-like [2] |
Density | 1.2475 g/cm3 [3] |
Melting point | 133 °C (271 °F; 406 K) [3] |
Boiling point | 300 °C (572 °F; 573 K) [3] |
500 mg/L [3] | |
Acidity (pKa) | 4.44 |
−7.836×10−5 cm3/mol | |
Hazards | |
GHS labelling: | |
Warning | |
H315, H319, H335 | |
P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501 | |
NFPA 704 (fire diamond) | |
Flash point | >100 °C (212 °F; 373 K) [3] |
Related compounds | |
Related compounds | Benzoic acid, Phenylacetic acid, Phenylpropanoic acid |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Cinnamic acid is an organic compound with the formula C6H5-CH=CH-COOH. It is a white crystalline compound that is slightly soluble in water, and freely soluble in many organic solvents. [4] Classified as an unsaturated carboxylic acid, it occurs naturally in a number of plants. It exists as both a cis and a trans isomer, although the latter is more common. [5]
Cinnamic acid is a central intermediate in the biosynthesis of a myriad of natural products including lignols (precursors to lignin and lignocellulose), flavonoids, isoflavonoids, coumarins, aurones, stilbenes, catechin, and phenylpropanoids. Its biosynthesis involves the action of the enzyme phenylalanine ammonia-lyase (PAL) on phenylalanine. [6]
It is obtained from oil of cinnamon, or from balsams such as storax. [4] It is also found in shea butter.[ citation needed ] Cinnamic acid has a honey-like odor; [2] and its more volatile ethyl ester, ethyl cinnamate, is a flavor component in the essential oil of cinnamon, in which related cinnamaldehyde is the major constituent. It is also found in wood from all species of trees. [7]
Cinnamic acid was first synthesized by the base-catalysed condensation of acetyl chloride and benzaldehyde, followed by hydrolysis of the acid chloride product. [5] In 1890, Rainer Ludwig Claisen described the synthesis of ethyl cinnamate via the reaction of ethyl acetate with benzaldehyde in the presence of sodium as base. [8] Another way of preparing cinnamic acid is by the Knoevenagel condensation reaction. [9] The reactants for this are benzaldehyde and malonic acid in the presence of a weak base, followed by acid-catalyzed decarboxylation. It can also be prepared by oxidation of cinnamaldehyde, condensation of benzal chloride and sodium acetate (followed by acid hydrolysis), and the Perkin reaction. The oldest commercially used route to cinnamic acid involves the Perkin reaction, which is given in the following scheme [5]
Cinnamic acid, obtained from autoxidation of cinnamaldehyde, is metabolized into sodium benzoate in the liver. [11]
Cinnamic acid is used in flavorings, synthetic indigo, and certain pharmaceuticals. A major use is as a precursor to produce methyl cinnamate, ethyl cinnamate, and benzyl cinnamate for the perfume industry. [4] Cinnamic acid is a precursor to the sweetener aspartame via enzyme-catalysed amination to give phenylalanine. [5] Cinnamic acid can dimerize in non-polar solvents resulting in different linear free energy relationships. [12]
Benzoic acid is a white solid organic compound with the formula C6H5COOH, whose structure consists of a benzene ring with a carboxyl substituent. The benzoyl group is often abbreviated "Bz", thus benzoic acid is also denoted as BzOH, since the benzoyl group has the formula –C6H5CO. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, which was for a long time its only source.
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.
An acetate is a salt formed by the combination of acetic acid with a base. "Acetate" also describes the conjugate base or ion typically found in aqueous solution and written with the chemical formula C
2H
3O−
2. The neutral molecules formed by the combination of the acetate ion and a positive ion are also commonly called "acetates". The simplest of these is hydrogen acetate with corresponding salts, esters, and the polyatomic anion CH
3CO−
2, or CH
3COO−
.
Cinnamaldehyde is an organic compound with the formula() C6H5CH=CHCHO. Occurring naturally as predominantly the trans (E) isomer, it gives cinnamon its flavor and odor. It is a phenylpropanoid that is naturally synthesized by the shikimate pathway. This pale yellow, viscous liquid occurs in the bark of cinnamon trees and other species of the genus Cinnamomum. The essential oil of cinnamon bark is about 90% cinnamaldehyde. Cinnamaldehyde decomposes to styrene because of oxidation as a result of bad storage or transport conditions. Styrene especially forms in high humidity and high temperatures. This is the reason why cinnamon contains small amounts of styrene.
The Tishchenko reaction is an organic chemical reaction that involves disproportionation of an aldehyde in the presence of an alkoxide. The reaction is named after Russian organic chemist Vyacheslav Tishchenko, who discovered that aluminium alkoxides are effective catalysts for the reaction.
Hippuric acid is a carboxylic acid and organic compound. It is found in urine and is formed from the combination of benzoic acid and glycine. Levels of hippuric acid rise with the consumption of phenolic compounds. The phenols are first converted to benzoic acid, and then to hippuric acid and excreted in urine.
Mandelic acid is an aromatic alpha hydroxy acid with the molecular formula C6H5CH(OH)CO2H. It is a white crystalline solid that is soluble in water and polar organic solvents. It is a useful precursor to various drugs. The molecule is chiral. The racemic mixture is known as paramandelic acid.
'DibenzylideneacetoneDibenzylideneacetone' or dibenzalacetone, often abbreviated dba, is an organic compound with the formula C17H14O. It is a pale-yellow solid insoluble in water, but soluble in ethanol.
The phenylpropanoids are a diverse family of organic compounds that are synthesized by plants from the amino acids phenylalanine and tyrosine. Their name is derived from the six-carbon, aromatic phenyl group and the three-carbon propene tail of coumaric acid, which is the central intermediate in phenylpropanoid biosynthesis. From 4-coumaroyl-CoA emanates the biosynthesis of myriad natural products including lignols, flavonoids, isoflavonoids, coumarins, aurones, stilbenes, catechin, and phenylpropanoids. The coumaroyl component is produced from cinnamic acid.
Flavones are a class of flavonoids based on the backbone of 2-phenylchromen-4-one (2-phenyl-1-benzopyran-4-one).
The Erlenmeyer–Plöchl azlactone and amino acid synthesis, named after Friedrich Gustav Carl Emil Erlenmeyer who partly discovered the reaction, is a series of chemical reactions which transform an N-acyl glycine to various other amino acids via an oxazolone.
In enzymology, a trans-cinnamate 4-monooxygenase (EC 1.14.14.91) is an enzyme that catalyzes the chemical reaction
The enzyme phenylalanine ammonia lyase (EC 4.3.1.24) catalyzes the conversion of L-phenylalanine to ammonia and trans-cinnamic acid.:
Rosavin are a family of cinnamyl mono- and diglycosides that are key ingredients of Rhodiola rosea L.,. R. rosea is an important medicinal plant commonly used throughout Europe, Asia, and North America, that has been recognized as a botanical adaptogen by the European Medicines Agency. Rosavin production is specific to R. rosea and R. sachalinenis, and the biosynthesis of these glycosides occurs spontaneously in Rhodiola roots and rhizomes. The production of rosavins increases in plants as they get older, and the amount of the cinnamyl alcohol glycosides depends on the place of origin of the plant.
Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful.
The biosynthesis of cocaine has long attracted the attention of biochemists and organic chemists. This interest is partly motivated by the strong physiological effects of cocaine, but a further incentive was the unusual bicyclic structure of the molecule. The biosynthesis can be viewed as occurring in two phases, one phase leading to the N-methylpyrrolinium ring, which is preserved in the final product. The second phase incorporates a C4 unit with formation of the bicyclic tropane core.
α-Phenylcinnamic acid is a phenylpropanoid, or, more specifically, a derivative of cinnamic acid. It has the formula C15H12O2 and appears as an off-white crystalline solid.
The biosynthesis of phenylpropanoids involves a number of enzymes.
Umbellic acid is a hydroxycinnamic acid. It is an isomer of caffeic acid.
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