Absolute configuration of (1S,2S)-3-methyl-2-phenyl-2,3-dihydro-thia-zolo[2,3-b]quinazolin-5-one.

The absolute structure of the molecule in the crystal of the title compound, C(17)H(14)N(2)OS, was determined by the refinement of the Flack parameter to 0.0 (2) based on 1011 Friedel pairs. The quinazoline ring is essentially planar, with a maximum deviation of 0.037 (2) Å. The thia-zole ring is distorted from planarity [maximum deviation = 0.168 (2) Å] and adopts a slightly twisted envelope conformation, with the C atom as the flap atom. The central thia-zole ring makes dihedral angles of 7.01 (8) and 76.80 (10)° with the quinazoline and phenyl rings, respectively. The corresponding angle between the quinazoline and phenyl rings is 3.74 (9)°. In the crystal, there are no classical hydrogen bonds but stabilization is provided by weak C-H⋯π inter-actions, involving the centroids of the phenyl rings.