5-Chloro-5′′-(4-chlorobenzylidene)-4′-(4-chlorophenyl)-1′,1′′-dimethyldispiro[indoline-3,2′-pyrrolidine-3′,3′′-piperidine]-2,4′′-dione

The racemic title compound, C30H26Cl3N3O2, comprises two spiro links, the first connecting the piperidine and pyrrolidine rings and the other connecting the indole and pyrrolidine rings. The piperidine ring adopts a half-chair conformation, while the pyrrolidine ring has an envelope conformation with the unsubstituted C atom as the flap. The dihedral angles between the two p-Cl-substituted benzene rings and the indole ring are 33.13 (14) and 54.11 (14)°. In the crystal, molecules form inversion dimers through pairs of N—H⋯O hydrogen bonds [graph set R 2 2(8)]. Aromatic C—H⋯O hydrogen bonds extend these dimers into a ribbon structure, enclosing R 2 2(14) ring motifs, along the a-axis direction.

The racemic title compound, C 30 H 26 Cl 3 N 3 O 2 , comprises two spiro links, the first connecting the piperidine and pyrrolidine rings and the other connecting the indole and pyrrolidine rings. The piperidine ring adopts a half-chair conformation, while the pyrrolidine ring has an envelope conformation with the unsubstituted C atom as the flap. The dihedral angles between the two p-Cl-substituted benzene rings and the indole ring are 33.13 (14) and 54.11 (14) . In the crystal, molecules form inversion dimers through pairs of N-HÁ Á ÁO hydrogen bonds [graph set R 2 2 (8)]. Aromatic C-HÁ Á ÁO hydrogen bonds extend these dimers into a ribbon structure, enclosing R 2 2 (14) ring motifs, along the a-axis direction.

Introduction
Spiropyrrolidinyl-oxindole represents the main alkaloid skeleton of naturally occurring substances characterized by promising biological and/or pharmacological properties. In continuation of our research program directed towards synthesis of biologically active compounds possessing this motif (Farag et al., 2014a-c;George et al., 2013;Girgis et al., 2012Girgis et al., , 2009aMoustafa et al., 2012), a novel analog, C 30 H 26 Cl 3 N 3 O 2 , is described in the present study utilizing a facile regio-as well as stereoselective procedure.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1. The relatively large ratio of minimum to maximum corrections applied in the multiscan process reflect changes in the illuminated volume of the crystal. Changes in illuminated volume were kept to a minimum, and were taken into account (Görbitz, 1999) by the multi-scan inter-frame scaling [DENZO/SCALEPACK (Otwinowski & Minor, 1997)]. The H atoms were all located in a difference map, but those attached to carbon atoms were repositioned geometrically and initially refined with soft restraints on the bond lengths and angles to regularise their geometry (C-H in the range 0.93-0.98, N-H in the range 0.86-0.89, N-H to 0.86 and O-H = 0.82 Å) and U> iso (H) (in the range 1.2-1.5 times U eq of the parent atom), after which the positions were refined with riding constraints (Cooper et al., 2010).
Also present in the molecule is an intramolecular C38-H···π interaction with the ring centroid (Cg) of the fivemembered C28-N30 ring.

Figure 1
The title compound with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radius.