(S)-tert-Butyl 2-(methylamino)propanoate hydrochloride is a chiral organic compound featuring a methylamino group and a tert-butyl ester moiety. It is the hydrochloride salt of the corresponding amino ester, which enhances its stability and handling properties. The compound is characterized by its (S)-configuration at the chiral center, making it a valuable source of enantiomerically pure building blocks. This compound is primarily employed as a key chiral intermediate in pharmaceutical synthesis. Its structure, containing a protected amino acid ester, makes it particularly useful for constructing more complex molecules, especially in the development of active pharmaceutical ingredients (APIs). It serves as a crucial precursor in the synthesis of various drug candidates, including those targeting the central nervous system and other therapeutic areas where chirality is critical for biological activity. As a versatile chiral synthon, it is widely used in medicinal chemistry research and process development. The tert-butyl ester group provides a convenient protecting group that can be cleaved under mild acidic conditions to reveal the free carboxylic acid, allowing for further functionalization. Its availability in high enantiomeric purity supports the production of stereochemically defined final products.