(3E,5E)-3,5-Bis(4-methylbenzylidene)-1-[3-(piperidin-1-yl)propanoyl]piperidin-4-one

In the title compound, C29H34N2O2, the central piperidine ring adopts a half-chair conformation, whereas the terminal one adopts a chair conformation. The mean plane of the central piperidine ring [maximum deviation = 0.384 (2) Å] makes dihedral angles of 64.82 (13) and 17.55 (13)° with the benzene rings. In the crystal, molecules are linked into a tape along the b axis via C—H⋯O interactions, generating R 2 2(20) and R 2 1(6) graph-set motifs. C—H⋯π interactions are observed between the tapes.

In the title compound, C 29 H 34 N 2 O 2 , the central piperidine ring adopts a half-chair conformation, whereas the terminal one adopts a chair conformation. The mean plane of the central piperidine ring [maximum deviation = 0.384 (2) Å ] makes dihedral angles of 64.82 (13) and 17.55 (13) with the benzene rings. In the crystal, molecules are linked into a tape along the b axis via C-HÁ Á ÁO interactions, generating R 2 2 (20) and R 2 1 (6) graph-set motifs. C-HÁ Á Á interactions are observed between the tapes.
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009). Due to these reasons, the crystal structure determination of the title compound was carried out and the results are presented in this paper.
Experimental 1-Acryloyl-3,5-dibenzylidenepiperidin-4-one was synthesized as reported in the literature (Dimmock et al., 2001). The title compound was prepared by refluxing 1-acryloyl-3,5-dibenzylidenepiperidin-4-one (0.6 mmol) with piperidine (0.6 mmol) in ethanol. After completion of the reaction as evident from TLC, the mixture was poured into ice. The precipitated solid was filtered and washed with water. The pure solid was then recrystallized from ethanol to afford the title compound as yellow crystals.

Refinement
All H atoms were positioned geometrically (C-H = 0.95-0.99 Å) and refined using a riding model with U iso (H) = 1.2 or 1.5U eq (C). A rotating group model was applied to the methyl groups.

Figure 1
The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme.

Figure 2
The crystal packing of the title compound. The H atoms not involved in the intermolecular interactions (dashed lines) have been omitted for clarity.   (Cosier & Glazer, 1986) operating at 100.0 (1) K. 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. Symmetry codes: (i) −x, y+1/2, −z+1/2; (ii) −x, y−1/2, −z+1/2; (iii) x+1, y, z; (iv) −x+1, y−1/2, −z+1/2.