D-Threonine methyl ester hydrochloride is a chiral amino acid derivative, specifically the methyl ester hydrochloride salt of D-threonine. It is a white to off-white crystalline powder. The compound features both an ester and an amine functional group, protected as its hydrochloride salt, making it a versatile chiral building block. Its primary application is in the pharmaceutical industry as a key chiral intermediate. It is extensively used in the synthesis of various active pharmaceutical ingredients (APIs) and complex molecules, particularly those requiring the specific stereochemistry of D-threonine. For example, it serves as a crucial precursor in the production of certain antibiotics and other therapeutic agents where the D-configuration is essential for biological activity. In synthetic chemistry, it is valued as a protected form of D-threonine, facilitating peptide coupling reactions and the construction of more complex chiral structures. Its use is critical for introducing the threonine moiety with controlled stereochemistry into target molecules during research and development processes.