(S)-3-Amino-4-(3-chlorophenyl)butanoic acid hydrochloride is a chiral amino acid derivative featuring a 3-chlorophenyl substituent. It serves as a key synthetic intermediate in the preparation of various pharmaceutical compounds. This compound is notably utilized in the synthesis of (S)-Baclofen, a selective agonist for the GABA_B receptor. Baclofen is a clinically important muscle relaxant and antispastic agent used to treat conditions such as multiple sclerosis and spinal cord injuries. The (S)-enantiomer is the pharmacologically active form, making this chiral intermediate crucial for producing the therapeutically effective agent. As a building block containing both an amino group and a carboxylic acid functionality, it is amenable to further chemical modifications. Its synthesis and application are of significant interest in medicinal chemistry for developing central nervous system (CNS) active drugs.