CAS 21731-56-6 appears in our catalog under these names: 4-(Methylsulfonyl)-2-nitroaniline, 95%, 4–(Methylsulfonyl)–2–nitroaniline, 4-(Methylsulfonyl)-2-nitroaniline, 97%, 97%, 4-(Methylsulfonyl)-2-nitroaniline. Offered by: Combi-blocks, GLPBio, Chemat, Fluorochem. Available pack sizes: 1g, 10g, 25g, 5g, 100mg, 250mg.