Methyl 1-ethyl-3′-[hydroxy(naphthalen-1-yl)methyl]-1′-methyl-2-oxospiro[indoline-3,2′-pyrrolidine]-3′-carboxylate

In the title compound, C27H28N2O4, the pyrrolidine ring adopts a twist conformation. The plane of the indole ring is almost perpendicular to that of the pyrrolidine ring, making a dihedral angle of 88.50 (6)°. The planes of the naphthyl ring system and the pyrrolidine ring are tilted by an angle of 55.86 (5)°. The molecular conformation is stabilized by intramolecular O—H⋯O and O—H⋯N hydrogen bonds.

In the title compound, C 27 H 28 N 2 O 4 , the pyrrolidine ring adopts a twist conformation. The plane of the indole ring is almost perpendicular to that of the pyrrolidine ring, making a dihedral angle of 88.50 (6) . The planes of the naphthyl ring system and the pyrrolidine ring are tilted by an angle of 55.86 (5) . The molecular conformation is stabilized by intramolecular O-HÁ Á ÁO and O-HÁ Á ÁN hydrogen bonds.

Related literature
For general background to spiro compounds and their biological activity, see: Pradhan et al. (2006); For uses of pyrrolidine derivative, see: Amal Raj et al. (2003); For conformation studies, see: Nardelli (1983 Table 1 Hydrogen-bond geometry (Å , ). Supporting information for this paper is available from the IUCr electronic archives (Reference: BT6950).

Comment
Spiro compounds have received considerable interest due to their biological properties (Pradhan et al., 2006). In addition, pyrrolidine derivatives are found to have anticonvulsant, antimicrobial and antifungal activities against various pathogens (Amal Raj et al., 2003). In view of their importance, the crystal structure determination of the title compound was carried out and the results are presented herein. In the title molecule (  Table 1).

Experimental
A mixture of methyl 2-(hydroxy(naphthalen-1-yl)methyl)acrylate (1 mmol), N-ethyl isatin (1.1 mmol) and sarcosine (1.1 mmol) was refluxed in methanol until completion of the reaction was evidenced by TLC analysis. After completion of the reaction the solvent was evaporated under reduced pressure. The reaction mixture was dissolved in ethyl acetate and washed with water followed by brine solution. The organic layer was separated and evaporated under reduced pressure.
The crude mixture was purified by column chromatography using ethyl acetate and hexane as eluent (3: 7). The product was dissolved in ethyl acetate and heated for two minutes. The resulting solution was subjected to crystallization by slow evaporation of the solvent for 48 h resulting in the formation of single crystals

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.