Ethyl 4-(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)-6-methyl-2-oxo-1,2,3,4-tetra-hydro-pyrimidine-5-carboxyl-ate.

In the title compound, C(18)H(19)ClN(4)O(3), the dihydro-pyrimidin-one ring adopts a flattened boat conformation. The dihedral angle between the phenyl and pyrazole rings is 43.39 (6)°. An intra-molecular C-H⋯O contact generates an S(8) ring motif that stabilizes the mol-ecular conformation and precludes the carbonyl O atom of the ester group from forming inter-molecular inter-actions. Mol-ecules are linked into centrosymmetric dimers by pairs of N-H⋯O hydrogen bonds and the dimers are linked into infinite chains along [101] by N-H⋯N hydrogen bonds.