In the title compound, C(14)H(13)N(3)O(3), the two six-membered rings are oriented at a dihedral angle of 15.17 (11)° and an intra-molecular O-H⋯O hydrogen bond occurs. In the crystal, mol-ecules inter-act by way of N-H⋯O, O-H⋯N and C-H⋯O hydrogen bonds, thereby generating S(5) chain and R(2) (1)(7) ring motifs.