Abstract: The(Z), (E)-or-chlorocinnamic acid with different substituents on the aromatic ring could be obtained by the alkaline elimination of α,β-dichlorophen-ylpropionic acids. The position of the substituents on the benzene ring showed important influence on the ratio of the (Z) and (E) isomers.The substituted (Z), (E)-α-chlorocinnamic acids were converted into corresponding (Z), (E)-α-chlorocinnamamides by means of acid chlorides and amin-olysis. After chromatography, we isolated ten pairs of geometric isomers including (z) and (E)-m-chloro-α-chloro-N-sec-butyl-cinnamamides.The configurations of α-chlorocinnamamides were assigned based on UV λ_max, ε_maxand chemical shifts of amide and olefinic protons. The values of UV λ_max, ε_maxand of chemical shifts (ppm) were greater for (Z) form and less for (E) form. The configurations were also confirmed by X-ray diffraction.Among ten pairs of isomers, (Z)-p-bromo-α-chlorocinnamoyl sec-butyl-amine was found to be more potent in anticonvulsive activity than others. The pharmacological evaluation showed that the configuration and the substituents at amide group displayed important effect on the biological activity.

Key words: a-Chlorocinnamamide, Anticonvulsive activity