CAS 571176-82-4 appears in our catalog under these names: (2S,4R)-4-(Acetylthio)-2-(((aminosulfonyl)((1,1-dimethylethoxy)carbonyl)amino)methyl)-1-pyrrolidinecarboxylic Acid (4-Nitrophenyl) Ethyl Ester, Doripenem 4R Isomer Impurity, Doripenem Impurity 15. Offered by: TRC, Chemat Brand, Hubei YoungXin. Available pack sizes: 100mg, on request, 10mg, 25mg, 50mg, 200mg.