Ethyl 5-methyl-4-oxo-3-phenyl-2-propylamino-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxylate

The title compound, C19H21N3O3S, was synthesized via the aza-Wittig reaction of functionalized iminophosphorane with phenyl isocyanate under mild conditions. In the molecule, the fused thienopyrimidine ring system is essentially planar, with a maximum deviation of 0.072 (2) Å, and makes a dihedral angle of 60.11 (9)° with the phenyl ring. An intramolecular C—H...O hydrogen bond is present. The crystal packing is stabilized by intermolecular N—H...O and C—H...O hydrogen bonds.