Crystal structure of ethyl 1′,1′′-dimethyl-2′′,3-dioxo-3H-di­spiro­[benzo[b]thio­phene-2,3′-pyrrolidine-2′,3′′-indoline]-4′-carboxyl­ate

In the title compound, C(23)H(22)N(2)O(4)S, the pyrrolidine ring has an envelope conformation with the spiro C atom, shared with the indoline ring system, as the flap. The mean planes of the benzo­thio­phene and indoline ring systems are inclined to the mean plane of the pyrrolidine ring by 88.81 (8) and 79.48 (8)°, respectively, and to each other by 68.12 (5)°. In the crystal, mol­ecules are linked via C—H⋯O hydrogen bonds, forming chains propagating along [001].