N-(3,4-Dimethylphenyl)-4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide

Abstract

1,2-Benzothiazines similar to the title compound, C18H18N2O4S, are well known in the literature for their biological activities and are used as medicines in the treatment of inflammation and rheumatoid arthritis. The thiazine ring adopts a distorted half-chair conformation. The enolic H atom is involved in an intramolecular O—H...O hydrogen bond, forming a six-membered ring. In the crystal, molecules arrange themselves into centrosymmetric dimers by means of pairs of weak intermolecular N—H...O hydrogen bonds.