Amifostine: C~5~H~15~N~2~O~3~PS 3H~2~O. Mw: 268.27. (1) Ethanethiol, 2-[(3-aminopropyl)amino]-, dihydrogen phosphate (ester), trihydrate; (2) S-[2-[(3-Aminopropyl)amino]ethyl] dihydrogen phosphorothioate, trihydrate. CAS-112901-68-5; CAS-20537-88-6 (anhydrous)(1991).