Crystal structure of 14-methyl-11-(3-methyl-phen-yl)-12-oxa-8,14-di-aza-tetra-cyclo-[8.3.3.0(1,10).0(2,7)]hexa-deca-2(7),3,5-triene-9,13-dione

In the title compound, C21H20N2O3, the lactone ring adopts an envelope conformation with the quaternary C atom bonded to two other C atoms as the flap. The fused pyrrolidine ring adopts a twisted conformation about the Cq-N (q = quaternary) bond. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds generate R 2 (2)(8) loops. The dimers are linked into [110] chains by pairs of C-H⋯O inter-actions, which generate R 2 (2)(14) loops.