Dimethyl 8-acetyl-2-methyl-1,2-dihydro-quinoline-2,4-dicarboxyl-ate

In the title compound, C(16)H(17)NO(5), the six-membered N-containing ring has a half-boat form; the spiro C atom deviates by 0.34 (2) Å from the plane (r.m.s. deviation = 0.051 Å) defined by the N and four aromatic C atoms. Intra-molecular N-H⋯O hydrogen bonding generates an S(6) ring motif and the dihedral angle between the mean plane though the S(6) ring and that through the five-atom half-boat plane is 3.39 (2)°. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link mol-ecules into zigzag chains along [001] due to c-glide symmetry, and C-H⋯π inter-actions extend along [010].