In the title mol-ecule, C(20)H(19)N(3)O(4)S, the heterocyclic thia-zine ring adopts a half-chair conformation with the S and N atoms displaced by 0.492 (6) and 0.199 (6) Å, respectively, on opposite sides from the mean plane formed by the remaining ring atoms. The ethanone group lies at an angle of 9.4 (2)° with respect to the benzene ring, which lies almost perpendicular to the pyrazole ring, with a dihedral between the two planes of 78.07 (9)°. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds.