16-[(E)-4-Bromobenzylidene]-13-(4-bromophenyl)-2-hydroxy-11-methyl-1,11-diazapentacyclo[12.3.1.02,10.03,8.010,14]octadeca-3(8),4,6-triene-9,15-dione

In the title pyrrolidine compound, C30H24Br2N2O3, the two fused pyrrolidine rings adopt envelope and twisted conformations, whereas the piperidine ring adopts an envelope conformation. The essentially planar 2,3-dihydroindanone unit [maximum deviation = −0.0163 (19) Å] is inclined at interplanar angles of 14.29 (9) and 61.07 (9)° to the two benzene rings. In the crystal, adjacent molecules are linked into dimers by intermolecular O—H⋯N and C—H⋯O hydrogen bonds. Short intermolecular Br⋯Br interactions [3.5140 (6) Å] further interconnect these dimers into double dimeric columns along the b axis.


Comment
Highly functionalized pyrrolidines have gained much interest in the past few years as they constitute the main structural element of many natural and synthetic pharmacologically active compounds (Waldmann, 1995). Optically active pyrrolidines have been used as intermediates, chiral ligands or auxiliaries in controlled asymmetric synthesis (Suzuki et al., 1994;Huryn et al., 1991). In view of this importance, the crystal structure of the title compound has been carried out and the results are presented here.

Experimental
The title compound was synthesized according to a previously described procedure (Kumar et al., 2010a,b,c), and was recrystallized from ethyl acetate to afford pale yellow single crystals.

Refinement
Atom H1O3 was located from a difference Fourier map [O3-H1O3 = 0.82 (3) Å] and allowed to refine freely. The remaining H atoms were placed in their calculated positions, with C-H = 0.93 -0.97 Å, and refined using a riding model, with U iso = 1.2 or 1.5 U eq (C). A rotating group model was applied to the methyl group. Fig. 1. The molecular structure of the title compound, showing 30 % probability displacement ellipsoids for non-H atoms and the atom-numbering scheme.

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.