(S)-5-Phenylmorpholin-2-one hydrochloride is primarily utilized in the field of medicinal chemistry and pharmaceutical research. It serves as a key intermediate in the synthesis of various biologically active compounds, particularly those targeting neurological and psychiatric disorders. Its structural framework is often incorporated into the development of potential therapeutic agents, such as inhibitors or modulators of specific enzymes or receptors. Additionally, it is explored in the design of novel drug candidates for conditions like depression, anxiety, and other central nervous system-related diseases. Its chiral nature also makes it valuable in studies focusing on enantioselective synthesis and drug optimization.