(R,S)-2′-Amino-6′-methyl-2,5′,5′-trioxo-6′H-spiro­[indoline-3,4′-pyrano[3,2-c][2,1]benzo­thia­zine]-3′-carbo­nitrile di­methyl­formamide monosolvate

The title solvate, C(20)H(14)N(4)O(4)S·C(3)H(7)NO, comprises a stereogenic centre but the centrosymmetric space group causes the presence of the racemate in the crystal. The spiro-joined fragments are almost orthogonal, with a dihedral angle of 86.8 (2)° between the mean planes of the pyrane ring and the dihydroindolone ring system. The atoms of the indolinone bicycle are coplanar, with an r.m.s. deviation of 0.005 Å. In the crystal, pairs of N—H⋯O hydrogen bonds link the mol­ecules into centrosymmetric dimers which are linked to the di­methyl­formamide solvent mol­ecules by further N—H⋯O hydrogen bonds. N—H⋯N hydrogen bonds link neighbouring dimers into [010] chains.