Bis[5-meth­oxy-2-(meth­oxy­carbon­yl)phen­yl] methyl­phospho­nate

In the title phospho­nate, C₁₉H₂₁O₉P, the dihedral angle between the benzene rings is 63.33 (3)°, and the P atom has a distorted tetra­hedral geometry, with angles in the range 101.30 (6)–120.38 (6)°. No significant inter­molecular inter­actions are observed in the crystal structure, and π–π inter­actions between symmetry-related benzene rings are beyond 4 Å.

2-[(Z)-1,1-Dioxo-2-(2,4,5-tri­fluoro­benz­yl)-3,4-di­hydro-2H-1,2-benzo­thia­zin-4-yl­idene]acetic acid

In the title compound, C₁₇H₁₂F₃NO₄S, the heterocyclic thia­zine ring adopts a half-chair conformation and the dihedral angle between the benzene rings is 43.28 (9)°. The α,β-unsaturated C=C group is inclined at an angle of 21.0 (3)° to the benzene ring of the benzo­thia­zine moiety. In the crystal, inversion dimers linked by pairs of carb­oxy­lic acid O—H...O hydrogen bonds generate R₂²(8) loops. Each of the F atoms accepts a C_a—H...F (a = aromatic) hydrogen bond from an adjacent mol­ecule, resulting in (001) sheets.

2-[(E)-1,1-Dioxo-2-(2,4,5-tri­fluoro­benz­yl)-3,4-di­hydro-2H-1,2-benzo­thia­zin-4-yl­idene]acetic acid

In the asymmetric unit of the title compound, C₁₇H₁₂F₃NO₄S, there are two conformationally similar mol­ecules in which the heterocyclic thia­zine ring adopts a half-chair conformation, with the dihedral angle between the two benzene rings being 24.84 (8) and 37.42 (8)°. In the crystal, the mol­ecules form dimers through cyclic carb­oxy­lic acid O—H...O hydrogen-bonding associations [graph set R²₂(8)] and are extended into chains along [101] through weak C—H...O_sulfin­yl hydrogen bonds [graph set R²₂(14)]..