4-Methyl-2-(2-nitrobenzenesulfonamido)pentanoic acid

In the title compound, C(12)H(16)N(2)O(6)S, the S atom adopts a distorted tetra-hedral geometry with an O-S-O angle of 119.76 (13)°. The nitro group is twisted by 35.34 (2)° with respect to the aromatic ring; it accepts an N-H⋯O hydrogen bond, resulting in a S(7) motif. In the crystal, N-H⋯O and O-H⋯O hydrogen bonds connect the mol-ecules into an infinite chain along the a axis. The methyl C atoms of the isopropyl group are disordered in a 1:1 ratio.