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

Abstract

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 Ca—H...F (a = aromatic) hydrogen bond from an adjacent molecule, resulting in (001) sheets.