Investigation of Three Stilbene Derivatives by X-ray Crystallography and NMR Spectroscopy
摘要:
Crystal structure determinations demonstrate unambiguously the steric assignments of (Z)-2-hydroxy-3,3',4'-trimethoxystilbene (C17H18O4), (E)-2-hydroxy-3,3',4'-trimethoxystilbene (C17H18O4) and (E)-2-acetoxy-3,3',4'-trimethoxystilbene (C19H20O5) C-13 NMR data and UV data for the compounds are also reported. The steric assignments of structurally related compounds described in the literature are discussed on the basis of the crystallographic and spectral results.
The crystal structure determination demonstrates unambiguously that the title compound, 2-[(Z)-3,4-dimethoxyphenylethenyl]-6-methoxypheenyl acetate, C19H20O5, has the Z configuration. The title compound was prepared by decarboxylation of (E)-3-(2-acetoxy-3 -methoxyphenyl)-2-(3,4-dimethoxyphenyl)propenoic acid; this compound was in turn obtained by condensation of 2-acetoxy-3-methoxybenzaldehyde with (3,4-dimethoxyphenyl)acetic acid. H-1 NMR data for the titie compound and the isomeric (E)-2-acetoxy-3,3',4'-trimethoxystilbene are reported.