Allocinnamic acid

Allocinnamic acid is a cis-isomer of cinnamic acid, into which the cinnamic acid is easily converted.^[1][2]

Allocinnamic acid

Names
IUPAC name (Z)-3-phenylprop-2-enoic acid
Other names cis-β-carboxystyrene, cis-cinnamic acid;
Identifiers
CAS Number	102-94-3 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:35699
ChemSpider	10286933
ECHA InfoCard	100.262.470
EC Number	827-073-9
Gmelin Reference	279588
PubChem CID	5372954
UNII	YB7ZGY8NE2
CompTox Dashboard (EPA)	DTXSID001019000
InChI InChI=1S/C9H8O2/c10-9(11)7-6-8-4-2-1-3-5-8/h1-7H,(H,10,11)/b7-6- Key: WBYWAXJHAXSJNI-SREVYHEPSA-N
SMILES C1=CC=C(C=C1)C=CC(=O)O
Properties
Chemical formula	C9H8O6
Molar mass	212.157 g·mol−1
Appearance	colorless crystals
Density	1.49 g/cm³
Melting point	68 °C (154 °F; 341 K)
Boiling point	265 °C (509 °F; 538 K)
Solubility in water	soluble
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Allocinnamic acid was first discovered by Сarl Liebermann in 1890 in coca leaves^[3][4], then Liebermann found that this acid is formed during the reduction (by zinc dust in an alcoholic solution during boiling) of β-dibromopropiolic acid.

Physical properties

Allocinnamic acid crystallizes in the form of three crystalline modifications with melting points of 68 °C, 58 °C, and 42 °C.^[5][6] It is hardly soluble in water and cold ligroin, easily soluble in alcohol and ether, and does not change in dim light.^[7]

Chemical properties

When heated briefly with concentrated sulfuric acid, the compound turns into cinnamic acid.^[3]

It forms liquid anhydride with acetic anhydride, which turns into cinnamic acid anhydride when heated.