Synthesis of analogues of GABA. VII. (Z)- and (E)-4-Amino-3-(4-chlorophenyl)-but-2-enoic acids as unsaturated baclofen derivatives

Abstract

(Z)- and (E)-4-Amino-3-(4-chlorophenyl)but-2-enoic acids have been synthesized from 4-chloroacetophenone as conformationally restricted analogues of baclofen. The corresponding unsaturated lactam (4) has been catalytically reduced and hydrolysed to baclofen to demonstrate the suitability of (4) as a precursor for radiolabelled baclofen of high specific activity.