Dimorphism in (2Z)-2-benzylidene-N,7-dimethyl-3-oxo-5-phenyl-2,3-dihydro-5H-1,3-thiazolo[3,2-a]pyrimidine-6-carboxamide.

The title compound, C22H19N3O2S, crystallizes in two polymorphic forms having the same space group, viz. P-1, with Z' = 2 and Z' = 1. In both polymorphs, the planar thiazole ring is fused cis with the dihydropyrimidine ring, the carbamoyl group is in an extended conformation with an anticlinal orientation with respect to the pyrimidine ring, and the phenyl ring is attached to the pyrimidine ring approximately at a right angle. The two polymorphs have different interplanar angles between the phenyl and thiazole rings. The molecules are linked by N-H...O and C-H...O hydrogen bonds.