Crystal structures of ethyl (2S*,2'R*)-1'-methyl-2'',3-dioxo-2,3-di-hydro-dispiro-[1-benzo-thio-phene-2,3'-pyrrolidine-2',3''-indoline]-4'-carboxyl-ate and ethyl (2S*,2'R*)-5''-chloro-1'-methyl-2'',3-dioxo-2,3-di-hydro-dispiro-[1-benzo-thio-phene-2,3'-pyrrolidine-2',3''-indoline]-4'-carboxyl-ate

The title compounds, (I) and (II), are di­spiro-indole-pyrrolidine-benzo­thio­phene derivatives, with (II) having a chlorine substituent on the oxo­indole unit. As a result, the conformation of the two mol­ecules differs in the angle of inclination of the indole moiety with respect to the benzo­thio­phene ring system, with a dihedral angle of 71.59 (5) in (I) and 82.27 (7)° in (II).

In the title compounds, C₂₂H₂₀N₂O₄S, (I), and C₂₂H₁₉ClN₂O₄S, (II), the pyrrolidine rings have twist conformations on the spiro–spiro C—C bonds. In (I), the five-membered ring of the oxindole moiety has an envelope conformation with the spiro C atom as the flap, while in (II) this ring is flat (r.m.s. deviation = 0.042 Å). The mean planes of the pyrrolidine rings are inclined to the mean planes of the indole units [r.m.s deviations = 0.073 and 0.069 Å for (I) and (II), respectively] and the benzo­thio­phene ring systems (r.m.s. deviations = 0.019 and 0.034 Å for (I) and (II), respectively) by 79.57 (8) and 88.61 (7)° for (I), and by 81.99 (10) and 88.79 (10)° for (II). In both compounds, the eth­oxy­carbonyl group occupies an equatorial position with an extended conformation. The overall conformation of the two mol­ecules differs in the angle of inclination of the indole unit with respect to the benzo­thio­phene ring system, with a dihedral angle between the planes of 71.59 (5) in (I) and 82.27 (7)° in (II). In the crystal of (I), mol­ecules are linked via pairs of N—H⋯O hydrogen bonds, forming inversion dimers enclosing R₂²(14) loops. The dimers are linked via C—H⋯O and bifurcated C—H⋯O(O) hydrogen bonds, forming sheets lying parallel to (100). In the crystal of (II), mol­ecules are again linked via pairs of N—H⋯O hydrogen bonds, forming inversion dimers but enclosing smaller R₂²(8) loops. Here, the dimers are linked by C—H⋯O hydrogen bonds, forming ribbons propagating along [010].