In an attempt to obtain new compounds with binding activity at the GABAB receptor site, we report the synthesis of 3-amino-2-arylpropanoic acids, and the sulfonic, phosphonic and hydroxamic acid analogues. In addition, we report the synthesis of the isomer of phaclofen, 3-amino-1-(4-chlorophenyl)-propylphosphonic acid, and the higher homologue of baclofen, 5-amino-2-(4-chlorophenyl)pentanoic acid.