Title: a-Phenylcinnamic Acid
CAS Registry Number: 3368-16-9
CAS Name: a-(Phenylmethylene)benzeneacetic acid
Additional Names: 2,3-diphenylacrylic acid; 2,3-diphenylpropenoic acid; stilbene-a-carboxylic acid
Molecular Formula: C15H12O2
Molecular Weight: 224.25
Percent Composition: C 80.34%, H 5.39%, O 14.27%
Literature References: Prepn of cis-form: Buckles, Hausman, J. Am. Chem. Soc. 70, 415 (1948); Buckles, J. Chem. Educ. 27, 210 (1950); Buckles, Bremer, Org. Synth. coll. vol. IV, 777 (1963); B. H. Patwardhan, G. Bagavant, Indian J. Chem. 10, 59 (1972). Prepn of cis- and trans-forms: L. F. Fieser, Experiments in Organic Chemistry (Heath, Boston, 3rd ed., 1955) p 182. Isomerization studies: S. V. Kessar et al., Indian J. Chem. 20B, 4 (1981).
Derivative Type: cis-Form
CAS Registry Number: 91-47-4
Properties: Silky needles from ether + petr ether, mp 174°. pKa 6.1 in 60% ethanol. uv max (ethanol): 223, 280 nm (e 32100, 19500). Sol in hot water, methanol, ethanol, isopropanol, ether, benzene.
Melting point: mp 174°
pKa: pKa 6.1 in 60% ethanol
Absorption maximum: uv max (ethanol): 223, 280 nm (e 32100, 19500)
Derivative Type: trans-Form
CAS Registry Number: 91-48-5
Properties: Stout prisms from ether + petr ether, mp 138-139°. Less stable than the cis-form. pKa 4.8 in 60% ethanol. uv max (ethanol): 222, 289 nm (e 14500, 22500). More sol than the cis-form.
Melting point: mp 138-139°
pKa: pKa 4.8 in 60% ethanol
Absorption maximum: uv max (ethanol): 222, 289 nm (e 14500, 22500)
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