6-Formyl-2-naphthyl cis-1,5,7-trimethyl-2,4-dioxo-3-aza-bicyclo-[3.3.1]nonane-7-carboxyl-ate.

In the title compound, C23H23NO5, the C5N ring adopts an envelope conformation with a C atom as the flap, whilst the saturated C6 ring fused to it adopts a chair conformation. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R22(8) loops.