(S)-Dimethyl 2-hydroxysuccinate, also known as (S)-Dimethyl malate or L-Dimethyl malate, is a chiral diester derived from L-malic acid. It is a colorless to pale yellow liquid with the molecular formula C6H10O5. This compound serves as a crucial chiral building block in organic synthesis, particularly valued for its (S)-configured stereocenter and the presence of both ester and hydroxyl functional groups, which allow for diverse chemical transformations. 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 natural products. For instance, it is a fundamental starting material or intermediate in the production of angiotensin-converting enzyme (ACE) inhibitors, certain antitumor agents, and other bioactive molecules where the (S)-malate moiety is essential for biological activity. The ester groups facilitate further coupling reactions, while the hydroxyl group can be selectively modified. Beyond pharmaceuticals, L-Dimethyl malate finds use in the synthesis of chiral ligands for asymmetric catalysis and in materials science research. It is also a precursor for flavors and fragrances. As a handling note, it is generally stable under recommended storage conditions but should be protected from moisture.