Synthesis, Separation and Crystal Structures of E and Z Isomers of 3-(2,5-Dimethoxyphenyl)-2-(4-Methoxyphenyl)Acrylic Acid

Abstract

Synthesis, separation and X-ray crystal structures of E and Z isomers of 3-(2,5-dimethoxyphenyl)-2-(4-methoxyphenyl)acrylic acid are reported. Separation of E and Z isomers from a 1:1 mixture has been carried out by selective acidification of their sodium salts carefully controlling the pH of the solution. The structures of E and Z isomers were confirmed by determining crystal structures of these isomers using single crystal X-ray diffraction. The E isomer crystallizes in the P2₁/c space group with a = 11.493(2) Å, b = 5.5456(11) Å, c = 24.900(5) Å, α = 90°, β = 92.36(3)°, γ = 90°, Z = 4. The Z isomer crystallizes in the P2₁/c space group with a = 10.192(2) Å, b = 12.893(3) Å, c = 13.948(3) Å, α = 90°, β = 92.18(3)°, γ = 90°, Z = 4. Details of the synthesis and structural characterization and X-ray crystal structure determination of the title compounds are presented.

Index Abstract

Synthesis, Separation and Crystal Structures of E and Z Isomers of 3-(2,5-Dimethoxyphenyl)-2-(4-Methoxyphenyl)Acrylic Acid

Balachandra Chenna, Bidhan A. Shinkre, Shweta Patel, Samuel B. Owens Jr., Gary M. Gray, Sadanandan E. Velu*

Separation of E and Z isomers of 3-(2,5-dimethoxyphenyl)-2-(4-methoxyphenyl)acrylic acid from a 1:1 mixture has been carried out by selective acidification of their sodium salts and the structures of the individual isomers have been determined by X-ray single crystal diffraction.