The title compound, C(8)H(8)N(2)O(4), is almost planar (r.m.s. deviation = 0.037 Å) and an intra-molecular N-H⋯O hydrogen bond generates an S(6) ring. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R(2) (2)(8) loops. Inter-molecular N-H⋯O hydrogen bonds (involving the same H atom that forms the intra-molecular hydrogen bond) link the dimers into infinite sheet...

The asymmetric unit of the title compound, C(7)H(5)ClO(3), contains two mol-ecules; both feature an intra-molecular O-H⋯O hydrogen bond, which generates an S(6) ring. In the crystal, both mol-ecules form inversion dimers linked by pairs of O-H⋯O hydrogen bonds with R(2) (2)(8) ring motifs. The dimers are inter-linked by C-H⋯O inter-actions.

In the title compound, C(5)H(5)NO(3), the mol-ecule lies on a crystallographic mirror plane with one half-mol-ecule in the asymmetric unit. An intramolecular C-H⋯O inter-action is present. In the crystal, strong inter-molecular O-H⋯N hydrogen bonds result in the formation of a linear chain structure along [100], and there are also weak C-H⋯O hydrogen bonds between the chains which help to stabi...

The mol-ecule of the title compound, C(10)H(9)NO(5), is approximately planar, with the mean planes of the nitro, carboxyl and all-yloxy groups rotated by 8.1 (3), 7.9 (3) and 4.52 (18)°, respectively, from the plane of the benzene ring. Bond lengths in the aromatic ring are influenced by both electronic effects and strain induced by ortho-substitution. In the crystal structure, centrosymmetrica...

In the title compound, C(7)H(6)N(2)O(4), an intra-molecular N-H⋯O hydrogen bond generates an S(6) ring. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R(2) (2)(8) loops. Inter-molecular N-H⋯O and C-H⋯O hydrogen bonds then link the dimers, generating R(3) (3)(16)R(2) (1)(6) motifs. The whole mol-ecule is essentially planar, with the greatest deviation from the ...

In the title compound, C7H6FNO2, the mol-ecule is almost planar (r.m.s. deviation for the non-H atoms = 0.015 Å) and an intra-molecular N-H⋯O hydrogen bond closes an S(6) ring. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R2(2)(8) loops. Weak N-H⋯F hydrogen bonds, short F⋯F contacts [2.763 (2) Å] and aromatic π-π stacking inter-actions [centroid-centroid sep...