In the title compound, C11H12ClNO3, the N—C=O fragment is twisted from the plane of the attached benzene ring by 48.39 (12)°. The carb­oxy­lic acid group is involved in O—H⋯O hydrogen bonding, which links pairs of mol­ecules into centrosymmetric dimers. N—H⋯O hydrogen bonds link these dimers, related by translation along the a axis, into ribbons.

In the title compound, C12H9ClN2O4S, the dihedral angle between the aromatic rings is 70.27 (8)°. In the crystal, molecules are linked by pairs of N—H...O(S) hydrogen bonds, forming inversion dimers.

In the title compound, C15H15NO, the amide fragment has an anti conformation. The central amide group is tilted with respect to the benzoyl ring, forming a dihedral angle of 32.3 (5)°. The benzoyl and aniline rings make a dihedral angle of 59.6 (5)°. Mol­ecules are linked into infinite supra­molecular chains via N—H⋯O hydrogen bonds. The mol­ecule is disordered so that the aromatic rings are disposed across a twofold axis with equal occupancies.

In the title compound, C12H10N2O4S, the dihedral angle between the aromatic rings is 36.19 (18)°. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into C(4) chains running along the a axis.

In the crystal of the title compound, C13H12N2O4S, the conformation of the N—H bond in the –SO2—NH– segment is syn to the ortho-nitro group in the sulfonyl benzene ring. The mol­ecule is twisted at the S—N bond with a torsion angle of 76.55 (18)°. The dihedral angle between the planes of the rings is 72.64 (8)°. In the crystal, mol­ecules are linked by pairs of N—H⋯O(S) hydrogen bonds to form inversion dimers.

Key indicators: single-crystal X-ray study; T = 293 K; mean (C-C) = 0.007 Å; R factor = 0.083; wR factor = 0.159; data-to-parameter ratio = 13.4.In the crystal structure of the title compound, C 11 H 12 ClNO 3 , the asymmetric unit contains two independent molecules. The N-H bond in the amide segment is anti to the meta-Cl atom in the benzene ring, in both molecules. The amide and carboxyl C O bonds are also anti to each other and anti to the H atoms on the adjacent -CH 2 groups. Furthermore, the C O and O-H bonds of the acid group are in syn positions with respect to each other. The dihedral angles between the benzene ring and the amide group are 40.6 (2) and 44.9 (3) in the two independent molecules. In the crystal, molecules are packed into sheets parallel to the (113) plane through O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds. Related literature ExperimentalCrystal data

Key indicators: single-crystal X-ray study; T = 293 K; mean (C-C) = 0.006 Å; R factor = 0.063; wR factor = 0.180; data-to-parameter ratio = 13.3.In the molecule of the title compound, C 10 H 7 ClN 2 O 5 , the acyclic C C double bond is cis configured. The C O and O-H bonds of the acid group are in a relatively rare anti position to each other, due to the donation of intramolecular hydrogen bond to the amide by the carboxyl group. The nitro group is significantly twisted [dihedral angle = 66.9 (3) ] out of the plane of the remaining atoms, which are almost coplanar (r.m.s. deviation for non-H atoms except the nitro group = 0.202 Å ). In the crystal, N-HÁ Á ÁO hydrogen bonds link the molecules into zigzag chains running along the b axis. Related literature

In the title compound, C11H12N2O5, the conformation of the N—H bond in the amide segment is syn to the ortho-nitro group in the benzene ring. The amide C=O and the carboxyl C=O of the acid segment are syn to each other and both are anti to the H atoms on the adjacent –CH2 groups. Furthermore, the C=O and O—H bonds of the acid group are in syn positions with respect to each other. The dihedral angle between the benzene ring and the amide group is 36.1 (1)°. The amide H atom shows bifurcated intra­molecular hydrogen bonding with an O atom of the ortho-nitro group and an inter­molecular hydrogen bond with the carbonyl O atom of another mol­ecule. In the crystal, the N—H⋯O(C) hydrogen bonds generate a chain running along the [100] direction. Inversion dimers are formed via a pair of O—H⋯O(C) interactions, that form an eight-membered hydrogen-bonded ring involving the carboxyl group.