(S)-3-Aminopyrrolidine dihydrochloride is a chiral, heterocyclic organic compound featuring a pyrrolidine ring substituted with an amino group at the 3-position. It is commonly supplied as a white to off-white crystalline powder in its dihydrochloride salt form, which enhances its stability and solubility for synthetic applications. This compound serves as a crucial chiral building block in pharmaceutical research and development. Its primary application is as a key intermediate in the synthesis of various bioactive molecules and active pharmaceutical ingredients (APIs). Notably, it is extensively used in the preparation of protease inhibitors, including HIV-1 protease inhibitors and renin inhibitors, where the (S)-configured aminopyrrolidine moiety acts as a critical pharmacophore. It is also employed in the synthesis of other drug candidates targeting neurological and cardiovascular diseases. As a versatile synthon, it participates in diverse chemical transformations such as amide bond formation and reductive amination. Handling requires standard precautions for handling amine hydrochlorides, including the use of personal protective equipment in a well-ventilated area.