16-[(E)-Benzylidene]-2-hydroxy-12,13-diphenyl-1,11-diazapentacyclo[12.3.1.02,10.03,8.010,14]octadeca-3(8),4,6-triene-9,15-dione

In the title compound, C35H28N2O3, an intramolecular O—H⋯N hydrogen bonds generates a five-membered ring, producing an S(5) ring motif. The piperidone ring adopts a half-chair conformation and the two pyrrolidine rings adopt an envelope conformation. The dihedral angles formed between adjacent benzene rings are 74.39 (5) and 37.70 (6)°. In the crystal crystal, intermolecular C—H⋯O hydrogen bonds link molecules into dimers, which are further interconnected into two-dimensional networks parallel to the ac plane by intermolecular C—H⋯O hydrogen bonds. The crystal structure is consolidated by weak C—H⋯π interactions.

In the title compound, C 35 H 28 N 2 O 3 , an intramolecular O-HÁ Á ÁN hydrogen bonds generates a five-membered ring, producing an S(5) ring motif. The piperidone ring adopts a half-chair conformation and the two pyrrolidine rings adopt an envelope conformation. The dihedral angles formed between adjacent benzene rings are 74.39 (5) and 37.70 (6) . In the crystal crystal, intermolecular C-HÁ Á ÁO hydrogen bonds link molecules into dimers, which are further interconnected into two-dimensional networks parallel to the ac plane by intermolecular C-HÁ Á ÁO hydrogen bonds. The crystal structure is consolidated by weak C-HÁ Á Á interactions.

Comment
The 1,3-dipolar cycloaddition of azomethine ylides with olefinic dipolarophiles offers an excellent route for the construction of pyrrolidines (Tsuge & Kanemasa, 1989;Padwa, 1984). The chemistry of azomethine ylides has gained significance in recent years as it serves as an important route for the construction of nitrogen containing five-membered heterocycles, which are often central ring systems of numerous natural products (Daly et al., 1986;Waldmann, 1995). The pyrrolidine moiety is one of the significant core structures among the most extensively studied natural and synthetic heterocyclic compounds with remarkable medicinal activities (Monlineux & Pelletier, 1987).

Experimental
A mixture of 3,5-bis[(E)-phenylmethylidene]tetrahydro-4(1H)-pyridinone (0.100 g, 0.363 mmol), ninhydrin (0.065 g, 0.363 mmol) and phenylglycine (0.055 g, 0.363 mmol) were dissolved in methanol (10 ml) and refluxed for 1 h. After completion of the reaction as evident from TLC, the mixture was poured into water (50 ml). The solid precipitated was filtered and washed with water to afford the product which was recrystallized from ethyl acetate to reveal the title compound as colourless crystals.

Refinement
Atoms H1N1 and H1O1 were located from a difference Fourier map [N1-H1N1 = 0.904 (15) Å and O1-H1O1 = 0.863 (18) 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 U eq (C). Fig. 1. The molecular structure of the title compound, showing 30 % probability displacement ellipsoids for non-H atoms and the atom-numbering scheme. An intramolecular hydrogen bond is shown as dashed line.

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.