In the title compound, C(16)H(16)N(2)O(5), the dihedral angle between the two benzene rings is 4.2 (2)° and an intra-molecular O-H⋯O hydrogen bond generates an S(6) ring. In the crystal, mol-ecules are linked into layers lying parallel to the bc plane by O-H⋯O and N-H⋯O hydrogen bonds.