(3S)-3-(3-Methylphenyl)-β-alanine, with CAS number 701907-44-0, is a chiral non-natural amino acid derivative. It features a β-alanine backbone with a (3S)-configured stereocenter and a meta-methyl-substituted phenyl ring attached at the β-position. This specific stereochemistry and substitution pattern make it a valuable chiral building block. Its primary and significant application is in pharmaceutical research and development as a key chiral intermediate. It is specifically utilized in the synthesis of novel drug candidates, particularly those targeting neurological disorders. For instance, it serves as a crucial precursor in the preparation of potent and selective inhibitors of the glycine transporter 1 (GlyT1), which is a promising target for the treatment of schizophrenia and other cognitive impairments. As a chiral β-amino acid with an aromatic side chain, it falls under the category of specialty fine chemicals used in asymmetric synthesis. Its defined stereochemistry is essential for imparting the desired biological activity to the final drug molecule, highlighting its role beyond a simple amine synthon to a targeted pharmaceutical intermediate.