CAS 21957-58-4 appears in our catalog under these names: (S)–2–(4–Methylphenylsulfonamido)propanoic acid, (S)-2-(4-Methylphenylsulfonamido)propanoic acid, 98%, (S)-2-(4-Methylphenylsulfonamido)propanoic acid, 97%, 97%, N-Tosyl-L-alanine, Tos-Ala-OH, >98.0%(HPLC)(T). Offered by: GLPBio, Fluorochem, Chemat, TRC, TCI. Available pack sizes: 100g, 25g, 5g, 250mg, 1g, 2g, 500mg, 10g.