Abstract
(RS)-4-Amino-3-(4-chlorophenyl)butanoic acid (baclofen, 2) is the prototypic selective GABA(B)R agonist and is used clinically for the treatment of spasticity associated with brain and spinal cord injuries. Synthesis and GABA(B) receptor agonist activity of certain amino acids structurally related to baclofen (2) are reported. (RS)-4-amino-3-(4-ethynylphenyl)butanoic acid hydrochloride (1b) showed GABA(B) receptor agonist activity with EC50 = 240 mu M whereas (RS)-4-amino-3-(4-iodophenyl)butanoic acid hydrochloride (1c) emerged as the best GABA(B) receptor agonist congener in the synthesized compounds with ED50 = 32 mu M.