title: 2-[(Z)-1,1-Dioxo-2-(2,4,5-tri-fluoro-benz-yl)-3,4-di-hydro-2H-1,2-benzo-thia-zin-4-yl-idene]acetic acid.
abstract: In the title compound, C17H12F3NO4S, the heterocyclic thia-zine 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 benzo-thia-zine moiety. In the crystal, inversion dimers linked by pairs of carb-oxy-lic acid O-H⋯O hydrogen bonds generate R 2 (2)(8) loops. Each of the F atoms accepts a Ca-H⋯F (a = aromatic) hydrogen bond from an adjacent mol-ecule, resulting in (001) sheets.
authors.affiliation: School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
authors.forename: Shagufta
authors.initials: S
authors.lastname: Parveen
authors.affiliation: School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
authors.forename: Saghir
authors.initials: S
authors.lastname: Hussain
authors.affiliation: School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
authors.forename: Shaojuan
authors.initials: S
authors.lastname: Zhu
authors.affiliation: School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Hao
authors.affiliation: School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
authors.forename: Changjin
authors.initials: C
authors.lastname: Zhu