1′-Methyl-4′-[4-(trifluoromethyl)phenyl]dispiro[indan-2,2′-pyrrolidine-3′,2′′-indan]-1,3,1′′-trione

In the title compound, C28H20F3NO3, the pyrrolidine ring adopts a half-chair conformation. The other five-membered rings adopt envelope conformations with the spiro and methylene C atoms as the flap atoms. In the crystal, molecules are connected via weak C—H⋯O hydrogen bonds, forming sheets parallel to the bc plane.

In the title compound, C 28 H 20 F 3 NO 3 , the pyrrolidine ring adopts a half-chair conformation. The other five-membered rings adopt envelope conformations with the spiro and methylene C atoms as the flap atoms. In the crystal, molecules are connected via weak C-HÁ Á ÁO hydrogen bonds, forming sheets parallel to the bc plane.

Comment
As part of our ongoing search for novel heterocyclic compounds with antitubercular activity (Wei et al., 2011), our group has synthesized the title compound as described below.
In the crystal (Fig. 2), the molecules are connected via weak intermolecular C-H···O (Table 1) hydrogen bonds, forming two-dimensional networks parallel to the bc-plane.

Refinement
All hydrogen atoms were positioned geometrically [ C-H = 0.95-1.00 Å] and were refined using a riding model, with U iso (H) = 1.2 or 1.5 U eq (C). A rotating group model was applied to the methyl groups.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.