(S)-5-Hydroxypiperidin-2-one is a chiral heterocyclic compound featuring a piperidin-2-one (δ-lactam) core with a hydroxyl group at the 5-position. It is a white to off-white crystalline powder with a molecular formula of C5H9NO2 and a molecular weight of 115.13 g/mol. This compound is a key chiral building block derived from or related to natural amino acids, particularly (S)-glutamic acid. Its primary application is in pharmaceutical research and development as a versatile intermediate. The (S)-5-hydroxypiperidin-2-one scaffold is a privileged structure found in various bioactive molecules and drug candidates. It serves as a crucial precursor for synthesizing protease inhibitors, particularly hepatitis C virus (HCV) NS3/4A protease inhibitors, and other pharmacologically active compounds targeting neurological and infectious diseases. Its chiral nature and functional groups make it valuable for constructing complex molecular architectures. The compound is also utilized in the synthesis of modified peptides and peptidomimetics due to its structural similarity to proline and other cyclic amino acid derivatives. It is typically handled under standard laboratory conditions, and appropriate safety measures should be observed as with any fine chemical intermediate.