4-Oxo-6-(2-oxo-5-vinylpyrrolidin-1-yl)hexanoic Acid is derived from Ethyl Succinoyl Chloride (E818230), which is used in the synthesis of bivalent ligands for D2/D3 dopamine receptors. Also used in the preparation of antimicrobial pyrrolo-isoquinolinones. Vigabatrin Impurity 2