Methyl 3′-(2,5-dimethylbenzyl)-1′-methyl-2-oxo-4′-phenylspiro[indoline-3,2′-pyrrolidine]-3′-carboxylate chloroform monosolvate

In the title solvate, C29H30N2O3·CHCl3, the dihedral angle between the indole ring system (r.m.s. deviation = 0.050 Å) and the 4-methylpyrrolidine ring is 88.88 (8)°. The latter ring adopts an envelope conformation with the N atom as the flap. Its mean plane makes dihedral angles of 86.94 (11) and 42.08 (9)° with the phenyl and dimethylbenzene rings, respectively. The molecular conformation is stabilized by intramolecular C—H⋯O hydrogen bonds, which generate S(6) and S(9) ring motifs. The chloroform solvent molecule is linked to the organic molecule by a C—H⋯O hydrogen bond involving the carbonyl O atom of the carboxylate group. In the crystal, molecules are linked via bifurcated N—H⋯(N,O) and C—H⋯O hydrogen bonds, forming chains propagating along [001].

In the title solvate, C 29 H 30 N 2 O 3 ÁCHCl 3 , the dihedral angle between the indole ring system (r.m.s. deviation = 0.050 Å ) and the 4-methylpyrrolidine ring is 88.88 (8) . The latter ring adopts an envelope conformation with the N atom as the flap. Its mean plane makes dihedral angles of 86.94 (11) and 42.08 (9) with the phenyl and dimethylbenzene rings, respectively. The molecular conformation is stabilized by intramolecular C-HÁ Á ÁO hydrogen bonds, which generate S(6) and S(9) ring motifs. The chloroform solvent molecule is linked to the organic molecule by a C-HÁ Á ÁO hydrogen bond involving the carbonyl O atom of the carboxylate group. In the crystal, molecules are linked via bifurcated N-HÁ Á Á(N,O) and C-HÁ Á ÁO hydrogen bonds, forming chains propagating along [001].

Comment
Synthesis of spiro compounds has drawn considerable attention from chemists, in view of their very good antimycobacterial activity (Chande et al., 2005). Oxindole derivatives are known to be potent inhibitors of monoamine oxidase (MAO) in human urine and rat tissues (Glover et al., 1998) and potent antagonists of in vitro receptor binding by atrial natriuretic peptide besides possessing a wide range of central nervous system activities (Bhattacharya et al., 1982).
The molecular structure of the title compound is illustrated in Fig 1. In the molecule, there is C-H···O hydrogen bond, forming an S(6) and S(9) ring motif (Bernstein et al., 1995). The indole ring system is essentially planar with a maximum deviation of 0.0782 (17) Å for the atom C10. The mean plane of the indole ring system forms dihedral angle of 88.88 (8)° with central mean plane of pyrrolidine five membered ring. The latter forms a dihedral angle of 42.08 (10)° with the benzyl ring. Atom O1 significantly deviates from the mean plane of the indole ring system by 0.1965 (12) Å. The molecular dimensions in the title compound are in excellent agreement with the those reported for a related compound (Karthikeyan et al., 2014).

Refinement
The H atoms could all be located in difference electron-density maps. In the final cycles of refinement they were treated as riding atoms and their distances were geometrically constrained: C-H = 0.93 and 0.96 Å for CH and CH 3 H atoms, respectively, with U iso (H) = 1.5 U eq (C-methyl) and = 1.2U eq (C) for other H atoms.

Figure 1
The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level.   Table 1 for details).

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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.