Crystal structure of ethyl 1′,5-dimethyl-2′′,3-dioxo-3H-dispiro[benzo[b]thiophene-2,3′-pyrrolidine-2′,3′′-indoline]-4′-carboxylate
The title compound, C23H22N2O4S, crystallized with two independent molecules (AandB) in the asymmetric unit. They have very similar conformations with the pyrrolidine ring having a twisted conformation, on the Cspiro—Cspirobond, in both molecules. In moleculeA, the mean planes of the benzothiophene and indoline ring systems are inclined to the mean plane of the pyrrolidine ring by 87.59 (10) and 84.51 (11)°, respectively, and to one another by 72.69 (7)°. The corresponding angles in moleculeBare 87.15 (10), 84.58 (10) and 72.07 (7)°, respectively. In the crystal, theAandBmolecules are linked to one another by two N—H...O hydrogen bonds, forming a dimer. These dimers are linkedviaC—H...O hydrogen bonds, forming a three-dimensional structure.