Ethyl (2Z)-2-(3-methoxybenzylidene)-7-methyl-3-oxo-5-phenyl-2,3-dihydro-5H-1,3-thiazolo[3,2-a]pyrimidine-6-carboxylate

In the title compound, C24H22N2O4S, the central pyrimidine ring is significantly puckered, assuming a conformation intermediate between a boat and a screw boat. The nearly planar thiazole ring (r.m.s. deviation = 0.0258 angstrom) is fused with the pyriamidine ring, making a dihedral angle of 9.83 (7)degrees. The carboxyl group is in an extended conformation with an anti-periplanar orientation with respect to the dihydropyrimidine ring. The benzene ring linked at the chiral C atom is perpendicular to the pyrimidine ring [dihedral angle = 85.21 (8)degrees] whereas the phenyl ring is nearly coplanar, making a dihedral angle of 13.20 (8)degrees. An intramolecular C-H center dot center dot center dot S hydrogen bond is observed. The crystal packing is influenced by weak intermolecular C-H center dot center dot center dot pi interactions and pi-pi stacking between the thiazole and phenyl rings [centroid-centroid distance = 3.9656 (10) angstrom], which stack the molecules along the c axis.