1-Ethyl-4′-(1H-indol-3-ylcarbonyl)-1′-methyl-2,2′′-dioxodispiro[indoline-3,2′-pyrrolidine-3′,3′′-indoline]-4′-carbonitrile dimethyl sulfoxide monosolvate

In the title compound, C31H25N5O3·C2H6OS, the three indole/indoline units are all essentially planar with maximum deviations of 0.0172 (3), 0.053 (2) and 0.07 (2) Å. The pyrrolidine ring adopts an envelope conformation with the C atoms bearing the 1-ethyl-2-oxoindole substituent (in which the five-membered ring adopts a twisted conformation) as the flap. The dimethyl sulfoxide solvent molecule is disordered over two positions, with an occupancy factor ratio of 0.871 (4):0.129 (4). The solvent components are linked to the heterocyclic molecule via C—H⋯O and C—H⋯S hydrogen bonds. In the crystal, the solvent components are linked to the heterocyclic molecule via C—H⋯O and C—H⋯S interactions, forming R 2 2(10) ring motifs. The molecules are further connected into a chain along the a-axis direction via N—H⋯O hydrogen bonds.

In the title compound, C 31 H 25 N 5 O 3 ÁC 2 H 6 OS, the three indole/ indoline units are all essentially planar with maximum deviations of 0.0172 (3), 0.053 (2) and 0.07 (2) Å . The pyrrolidine ring adopts an envelope conformation with the C atoms bearing the 1-ethyl-2-oxoindole substituent (in which the five-membered ring adopts a twisted conformation) as the flap. The dimethyl sulfoxide solvent molecule is disordered over two positions, with an occupancy factor ratio of 0.871 (4):0.129 (4). The solvent components are linked to the heterocyclic molecule via C-HÁ Á ÁO and C-HÁ Á ÁS hydrogen bonds. In the crystal, the solvent components are linked to the heterocyclic molecule via C-HÁ Á ÁO and C-HÁ Á ÁS interactions, forming R 2 2 (10) ring motifs. The molecules are further connected into a chain along the a-axis direction via N-HÁ Á ÁO hydrogen bonds.
In the crystal structure of title compound, C 31 H 25 N 5 O 3 . C 2 H 6 OS, (Fig. 1), there is a dispiro centers system, which consists of two oxindole rings, an indole ring and a pyrrolidine ring. In crystals organic heterocycles moiety and solvent molecules connected by two intermolecular C-H···S and C-H···O hydrogen bonds (Table 1). The dimethyl sulfoxide solvent molecule is disordered over two positions with site occupancy factors 0.871 (4) and 0.129 (4).
The pyrrolidine ring (N3/C12/C13/C14/C10) adopts an envelope conformation with puckering parameters, q 2 = 0.402 (2)Å, φ(2) = 331.4 (3)°, and with atom C13 deviating by 0.256 (2)Å from the mean plane passing through the rest of the ring atoms (Cremer & Pople, 1975). The carbonitrile group is nearly perpendicular to pyrrolidine ring, as indicated In the crystal structure, pairs of molecules are linked by intermolecular C-H···O and C-H···S hydrogen bonds to generate R 2 2 (10) ring motifs (Bernstein et al., 1995). The molecules are further connected into a chain along the a axis via N-H···O intermolecular hydrogen bonds. The packing view of the title compound is shown in Fig. 2

Refinement
Positions of hydrogen atoms were localized from the difference electron density maps and their distances were geometrically constrained. The H atoms bound to the C atoms were treated as riding atoms,with C-H = 0.93Å and U iso (H) = 1.2U eq (C) for aromatic, C-H = 0.97Å and U iso (H) = 1.2U eq (C) for methylene and C-H = 0.96Å and U iso (H) = 1.5U eq (C) for methyl groups. The rotation angles for methyl groups were optimized by least squares. The N bonded H atoms were refined freely.   The packing structure of the title compound viewed along the c axis. H atoms not included in H-bonding have omited for clarity.  (2) Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ.