Caffeic Acid Phenethyl Ester (CAPE): Synthesis and X-Ray Crystallographic Analysis

The structure of caffeic acid phenethyl ester [2-propenoic acid, 3-(3, 4-dihydroxyphenyl)-, 2-phenethyl ester] (I), C17H16O4·1/2C6H6, synthesized by base-catalyzed alkylation of caffeic acid salt with β-bromoethylbenzene in HMPA (hexamethylphosphoramide) and recrystallized from benzene, was confirmed by single crystal X-ray diffraction. The crystals are triclinic, space group P 1, Z=2, unit cell dimension a=5.8129 (9) Å, b=11.122 (2) Å, c=13.226 (2) Å, α=97.080 (3)°, β=101.467 (3)°, γ=95.405 (3)°, V=825.4 (2) Å3, Dcalc=1.301 g/cm3, F(000)=342. The packing of the molecule is stabilized by intermolecular O1H…O4 (2.69 Å) and O1…HO2 (2.82 Å) hydrogen bonds.