(R,S)-2'-Amino-6'-methyl-2,5',5'-trioxo-6'H-spiro-[indoline-3,4'-pyrano[3,2-c][2,1]benzo-thia-zine]-3'-carbo-nitrile di-methyl-formamide monosolvate.

The title solvate, C20H14N4O4S·C3H7NO, 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†à . In the crystal, pairs of N-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers which are linked to the di-methyl-formamide solvent mol-ecules by further N-H⋯O hydrogen bonds. N-H⋯N hydrogen bonds link neighbouring dimers into [010] chains.