Crystal structures of ethyl (2S*,2 ' R*)-1 '-methyl-2 '',3-dioxo-2,3-dihydrodispiro[1-benzothiophene-2,3 '-pyrrolidine-2 ',3 ''-indoline]-4 '-carboxylate and ethyl(2S*,2 ' R*)-5 ''-chloro-1 '-methyl-2 '',3-dioxo-2,3-di-hydrodispiro[1-benzothiophene-2,3 '-pyrrolidine-2 ',3 ''-indoline]-4 '-carboxylate

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 angstrom). 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 angstrom for (I) and (II), respectively] and the benzothiophene ring systems (r.m.s. deviations = 0.019 and 0.034 angstrom for (I) and (II), respectively) by 79.57 (8) and 88.61 (7)degrees for (I), and by 81.99 (10) and 88.79 (10)degrees 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)degrees in (II). In the crystal of (I), molecules are linked via pairs of N-H center dot center dot center dot O hydrogen bonds, forming inversion dimers enclosing R-2(2)(14) loops. The dimers are linked via C-H center dot center dot center dot O and bifurcated C-H center dot center dot center dot O(O) hydrogen bonds, forming sheets lying parallel to (100). In the crystal of (II), molecules are again linked via pairs of N-H center dot center dot center dot O hydrogen bonds, forming inversion dimers but enclosing smaller R-2(2)(8) loops. Here, the dimers are linked by C-H center dot center dot center dot O hydrogen bonds, forming ribbons propagating along [010].