Abstract
In the molecule of the title compound, C10H9NO6S center dot H2O, the benzothiazine ring adopts an envelope conformation. An intramolecular N-H...O hydrogen bond results in the formation of a nonplanar five-membered ring which has a twisted conformation. In the crystal structure, intermolecular N-H...O,O-H...O and C-H...O hydrogen bonds link the molecules to form a three-dimensional network. There is a pi-pi contact between the benzene rings [centroid-centroid distance = 3.972 (2) angstrom].