3-[(3-Benzoyl-4-hy­droxy-1,1-dioxo-2H-1λ⁶,2-benzothia­zin-2-yl)meth­yl]benzo­nitrile

There are two independent mol­ecules in the asymmetric unit of the title compound, C₂₃H₁₇N₂O₄S, with significant differences in their conformations, e.g. the benzene rings of the benzothia­zine and benzonitrile units are inclined at 28.19 (10) and 17.89 (7)° in the two mol­ecules, with the centroids of the rings separated by 3.975 (2) and 3.637 (2) Å, respectively. Moreover, the N—C—C—C torsion angles involving the benzoyl group are 14.3 (5) and 8.2 (5)° in the two mol­ecules, showing different degrees of rotation of this group. In both mol­ecules, the heterocyclic thia­zine rings adopt half-chair conformations, with the S and N atoms displaced by 0.427 (6) and 0.365 (6) Å, respectively, in one mol­ecule and by 0.356 (6) and 0.432 (6) Å, respectively, in the other, on opposite sides of the mean planes formed by the remaining ring atoms. The crystal structure is stabilized by inter­molecular C—H...O hydrogen bonds and further consolidated by intra­molecular O—H...O hydrogen bonds.

2-(3,4-Dimethyl-5,5-dioxo-2H,4H-pyrazolo­[4,3-c][1,2]benzothia­zin-2-yl)-1-(4-meth­oxy­phen­yl)ethanone

In the title mol­ecule, C₂₀H₁₉N₃O₄S, the heterocyclic thia­zine ring adopts a half-chair conformation with the S and N atoms displaced by 0.492 (6) and 0.199 (6) Å, respectively, on opposite sides from the mean plane formed by the remaining ring atoms. The ethanone group lies at an angle of 9.4 (2)° with respect to the benzene ring, which lies almost perpendicular to the pyrazole ring, with a dihedral between the two planes of 78.07 (9)°. In the crystal, mol­ecules are linked by weak C—H...O hydrogen bonds.

2-[2-(2-Chloro­phen­yl)-2-oxoeth­yl]-2,3-dihydro-1λ⁶,2-benzothia­zole-1,1,3-trione

The asymmetric unit of the title compound, C₁₅H₁₀ClNO₄S, contains two independent conformers wherein the 2-chloro­phenyl group in one is rotated by approximately 180° compared to the other mol­ecule. This affects the S—N—C—C(=O) and N—C—C(=O)—C torsion angles giving vlaues of −87.0 (2) and 158.7 (2)° in one mol­ecule and −104.3 (2) and −173.4 (2)° in the other. The benzisothia­zole ring systems in the two mol­ecules are essentially planar (r.m.s. deviations = 0.017 and 0.010 Å) and form dihedral angles of 73.53 (7) and 73.26 (6)° with the benzene rings. In the crystal, there are weak π–π inter­actions between the benzene rings of the benzisothia­zole groups and symmetry-related chloro­benzene rings with centroid–centroid distances of 3.6178 (13) and 3.6267 (15) Å. In addition, pairs of weak inter­molecular C—H...O hydrogen bonds form inversion dimers which are connected by further C—H...O hydrogen bonds into a three-dimensional network.