3-[2-[2-[2-[2-[2-[2-[2-(2-Acetylsulfanyl-ethoxy)ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]propionic Acid-2,5-dioxo-pyrrolidin-1-yl Ester is used as a reactant in the synthesis of integrin antagonist conjugates for targeted delivery to cells expressing LFA-1.