Cinnamic acid

Cinnamic acid

Names
Preferred IUPAC name (2E)-3-Phenylprop-2-enoic acid
Other names Cinnamic acid trans-Cinnamic acid Phenylacrylic acid Cinnamylic acid 3-Phenylacrylic acid (E)-Cinnamic acid Benzenepropenoic acid Isocinnamic acid
Identifiers
CAS Number	140-10-3 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:35697 Y
ChEMBL	ChEMBL27246 Y
ChemSpider	392447 Y
ECHA InfoCard	100.004.908
IUPHAR/BPS	3203
KEGG	C00423 Y
PubChem	444539
UNII	U14A832J8D N
InChI InChI=1S/C9H8O2/c10-9(11)7-6-8-4-2-1-3-5-8/h1-7H,(H,10,11)/b7-6+ Y Key: WBYWAXJHAXSJNI-VOTSOKGWSA-N Y InChI=1/C9H8O2/c10-9(11)7-6-8-4-2-1-3-5-8/h1-7H,(H,10,11)/b7-6+ Key: WBYWAXJHAXSJNI-VOTSOKGWBT
SMILES O=C(O)\C=C\c1ccccc1
Properties
Chemical formula	C9H8O2
Molar mass	148.16 g·mol−1
Appearance	White monoclinic crystals
Density	1.2475 g/cm3
Melting point	133 °C (271 °F; 406 K)
Boiling point	300 °C (572 °F; 573 K)
Solubility in water	500 mg/L
Acidity (pKa)	4.44
Magnetic susceptibility (χ)	-78.36·10−6 cm3/mol
Hazards
EU classification (DSD)	Irritant (Xi)
R-phrases	R36
S-phrases	S25
NFPA 704	1 1 0
Flash point	> 100 °C (212 °F; 373 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Cinnamic acid is an organic compound with the formula C₆H₅CHCHCO₂H. It is a white crystalline compound that is slightly soluble in water, and freely soluble in many organic solvents. 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.

It is obtained from oil of cinnamon, or from balsams such as storax. It is also found in shea butter. Cinnamic acid has a honey-like odor; it and its more volatile ethyl ester (ethyl cinnamate) are flavor components in the essential oil of cinnamon, in which related cinnamaldehyde is the major constituent. Cinnamic acid is also part of the biosynthetic shikimate and phenylpropanoid pathways. Its biosynthesis is performed by action of the enzyme phenylalanine ammonia-lyase (PAL) on phenylalanine.

The original synthesis of cinnamic acid involves the Perkin reaction, which entails the base-catalysed condensation of acetic anhydride and benzaldehyde. Rainer Ludwig Claisen (1851–1930) described the synthesis of cinnamate esters by the reaction of benzaldehyde and esters. The reaction is known as the Aldol condensation (with accompanying hydrolysis of the anhydride). It can also be prepared from cinnamaldehyde and benzal chloride.