1-(2-Chlorobenzyl)-3-methyl-2,6-diphenylpiperidine

In the title compound, C25H26ClN, the piperidine ring has a chair conformation with all ring substituents in equatorial positions. The dihedral angle formed between the chlorobenzene ring and the flanking phenyl rings are 74.91 (18) and 47.86 (17)°. The chloro substituent is anti to the piperidine N atom. In the crystal, centrosymmetrically related molecules aggregate via π–π interactions occurring between chlorobenzene rings [centroid–centroid distance = 3.778 (2) Å] and these are linked into linear supramolecular chains along the a axis by C—H⋯π interactions occurring between the phenyl rings.

In the title compound, C 25 H 26 ClN, the piperidine ring has a chair conformation with all ring substituents in equatorial positions. The dihedral angle formed between the chlorobenzene ring and the flanking phenyl rings are 74.91 (18) and 47.86 (17) . The chloro substituent is anti to the piperidine N atom. In the crystal, centrosymmetrically related molecules aggregate viainteractions occurring between chlorobenzene rings [centroid-centroid distance = 3.778 (2) Å ] and these are linked into linear supramolecular chains along the a axis by C-HÁ Á Á interactions occurring between the phenyl rings.

Experimental
Cg1 is the centroid of the C20-C25 ring.

Comment
Piperidine derivatives are an important class of heterocyclic compounds with potential applications in medicinal chemistry as these can be frequently recognized in the structures of various synthetic targets as well as naturally occurring alkaloids (Ramalingan et al., 2004;Ramachandran et al., 2011). The title compound, (I), was designed and synthesized to evaluate its biological properties. The crystal structure determination was undertaken in order to establish conformational details.
In (I), Fig. 1, the piperidine ring has a chair conformation and all ring-substituents occupy equatorial positions. The dihedral angle formed between the C1-C6 benzene ring and the flanking C14-C19 and C20-C25 phenyl rings are 74.91 (18) and 47.86 (17)°, respectively; the dihedral angle between the phenyl rings is 58.93 (18)°. In a comparable molecule, having an extra C-bound methyl group (Ramalingan et al., 2012), these substituents were found to occupy the same positions. The chloro substituent is anti to the piperidine-N atom.
In the crystal packing, centrosymmetrically related molecules aggregate via π-π interactions occurring between chlorobenzene rings [inter-centroid distance = 3.778 (2) Å for symmetry operation 2 -x, 1 -y, 1 -z]. These are linked into linear supramolecular chains along the a axis by C-H···π interactions whereby a phenyl-H17 atom associates with the C20-C25 ring, Fig. 2 and Table 1. Chains aggregate into layers in the ab plane without specific intermolecular interactions between them, Fig. 3.
Extraction with diethyl ether followed by column chromatography separation using n-hexane/ethyl acetate (100:4) as an eluent eventually provided the pure title compound as a white solid. Re-crystallization was performed by slow evaporation of its ethanolic solution which afforded colourless plates. M.pt: 352-353 K. Yield: 83%.

Refinement
Carbon-bound H-atoms were placed in calculated positions [C-H = 0.95-1.00 Å, U iso (H) = 1.2-1.5U eq (C)] and were included in the refinement in the riding model approximation. The anisotropic displacement parameters for the C3 and C4 atoms were constrained to be nearly isotropic.

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.