1-[4-(4-Isopropyl-phen-yl)-6-methyl-2-sulfanyl-idene-1,2,3,4-tetra-hydro-pyrimidin-5-yl]ethanone.

In the title mol-ecule, C(16)H(20)N(2)OS, the heterocyclic ring adopts a slightly distorted flattened boat conformation, and the plane through the four coplanar atoms makes a dihedral angle of 86.98 (6)° with the benzene ring. The thione, acetyl and methyl groups lie on the opposite side of the heterocyclic mean plane to the isopropylphenyl group which has an axial orientation. A weak intra-molecular C-H⋯O hydrogen bond is observed. In the crystal, molecules are linked via N-H⋯O, N-H⋯S and C-H⋯S hydrogen bonds.