The complete mol-ecule of the title compound, C(20)H(19)NO(5)S(2), is generated by a crystallographic twofold axis and the O atom and N-H group attached to the central benzene ring are statistically disordered. The dihedral angle between the central and terminal benzene rings is 56.91 (5)° and that between the terminal benzene rings is 29.80 (5)°. In the crystal, N-H⋯O hydrogen bonding links the mol-ecules into sheets lying parallel to the ab plane.