Title: Caffeic Acid
CAS Registry Number: 331-39-5
CAS Name: 3-(3,4-Dihydroxyphenyl)-2-propenoic acid
Additional Names: 3,4-dihydroxycinnamic acid
Molecular Formula: C9H8O4
Molecular Weight: 180.16
Percent Composition: C 60.00%, H 4.48%, O 35.52%
Literature References: Constituent of plants, probably occurs in plants only in conjugated forms, e.g., chlorogenic acid. Isoln from green coffee: Wolfrom et al., J. Agric. Food Chem. 8, 58 (1960); from roasted coffee: Krasemann, Arch. Pharm. 293, 721 (1960). Formation by acid hydrolysis of chlorogenic acid: Fiedler, Arzneim.-Forsch. 4, 41 (1954); Whiting, Carr, Nature 180, 1479 (1957); Guern, C.A. 61, 9965h (1964). Synthesis: Hayduck, Ber. 36, 2935 (1903); Posner, J. Prakt. Chem. 82, 432 (1910); Mauthner, ibid. 142, 33 (1935); Pandya et al., Proc. Indian Acad. Sci. 9A, 511 (1939); Neish, Can. J. Biochem. Physiol. 37, 1431 (1959). Review: Herrmann, Pharmazie 11, 433 (1956).
Properties: Yellow crystals from concd aq solns. Monohydrate from dil solns. Dec 223-225° (softens at 194°). Rf values: Fiedler, loc. cit. Sparingly sol in cold water. Freely sol in hot water, cold alc. Alkaline solns turn from yellow to orange.
Derivative Type: Methyl ester
Molecular Formula: C10H10O4
Molecular Weight: 194.18
Percent Composition: C 61.85%, H 5.19%, O 32.96%
Properties: Colorless needles from water, mp 152-153°.
Melting point: mp 152-153°
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