c-3,t-3-Dimethyl-4-oxo-r-2,c-6-diphenyl­piperidine-1-carboxamide

M Thenmozhi; T Kavitha; S Ponnuswamy; M Jamesh; M N Ponnuswamy

doi:10.1107/S1600536809041579

. 2009 Oct 23;65(Pt 11):o2808. doi: 10.1107/S1600536809041579

c-3,t-3-Dimethyl-4-oxo-r-2,c-6-diphenylpiperidine-1-carboxamide

M Thenmozhi ^a, T Kavitha ^a, S Ponnuswamy ^b, M Jamesh ^b, M N Ponnuswamy ^a,^*

PMCID: PMC2971303 PMID: 21578400

Abstract

In the title compound, C₂₆H₂₆N₂O₂, the piperidinone ring adopts a distorted boat conformation. The two phenyl rings substituted at positions 2 and 6 of the piperidinone ring occupy axial and equatorial orientations, which are approximately perpendicular to each other [89.14 (8)°]. The phenylcarbamoyl group adopts an extended conformation. The crystal structure is stabilized by intermolecular C—H⋯O interactions.

Related literature

For general background to the pharmaceutical activity of piperidine derivatives, see: Mobio et al. (1989 ▶); Palani et al. (2002 ▶). For hybridization, see: Beddoes et al. (1986 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For ring conformational analysis, see: Cremer & Pople (1975 ▶); Nardelli (1983 ▶).

Experimental

Crystal data

C₂₆H₂₆N₂O₂
M _r = 398.49
Triclinic,
a = 9.6648 (2) Å
b = 10.7938 (3) Å
c = 11.4233 (3) Å
α = 101.303 (2)°
β = 90.158 (1)°
γ = 113.191 (1)°
V = 1069.91 (5) Å³
Z = 2
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 293 K
0.12 × 0.12 × 0.10 mm

Data collection

Bruker Kappa APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2001 ▶) T _min = 0.991, T _max = 0.992
26776 measured reflections
6362 independent reflections
4483 reflections with I > 2σ(I)
R _int = 0.027

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.129
S = 1.03
6362 reflections
278 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809041579/bt5059sup1.cif

e-65-o2808-sup1.cif^{(23.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809041579/bt5059Isup2.hkl

e-65-o2808-Isup2.hkl^{(305.1KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C18—H18⋯O2ⁱ	0.93	2.56	3.4488 (17)	161
C20—H20B⋯O1ⁱⁱ	0.96	2.52	3.4520 (17)	162

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

MT thanks Dr Babu Varghese, SAIF, IIT-Madras, Chennai, India, for his help with the data collection. SP thanks the UGC, India, for financial support.

supplementary crystallographic information

Comment

Several 2,6-disubstituted piperidine derivatives have fungicidal, herbicidal and bactericidal properties. Both the natural and synthetic piperidine derivatives exhibit high pharmaceutical values (Mobio et al., 1989). Piperidines have a favourable pharmacokinetic profile in rodents and primates, excellent oral bioavailability, and potent antiviral activity against a wide range of primary HIV-1 isolates and considered as promising new candidate for the treatment of HIV-1 infection (Palani et al., 2002).

The ORTEP plot of the molecule is shown in Fig. 1. The piperidine ring adopts distorted boat conformation, with the puckering amplitudes q2 = 0.5877 (13)°, q3 =-0.1100 (13)°, φ = 258.06 (12)° (Cremer & Pople, 1975) and asymmetry parameters Δ_s(C2)=Δ_s(C5) = 18.55 (12)° (Nardelli, 1983). The planar phenyl rings substituted at positions 2 and 6 occupy axial [70.71 (13)°] and equatorial [-162.73 (11)°] orientations and are approximately perpendicular to each other [89.14 (8)°]. One of the methyl groups attached at position 3 of the piperidine ring occupy equatorial [N1-C2-C3-C20 = 177.95 (10)°] orientation and other one is in axial [N1-C2-C3-C21 = 58.31 (12)°] orientation. The sum of the bond angles around N1[358.2 (3)°] indicates sp² hybridization (Beddoes et al., 1986).

The phenylcarbamoyl group attached to the N1 atom adopts an extended conformation which is evidenced from the torsion angle [N1-C7-N2-C8=]169.19 (11)°. The crystal structure is stabilized by C-H···O type of intermolecular interactions in addition to van der Waals forces. The C20-H20B···O1 interaction between the molecules lead to the dimer arrangement along the bc plane. These dimers are interconnected by C18-H18···O2 hydrogen bonds, which form a one dimensional chain running along a - axis (Fig. 2).

Experimental

A mixture of c-3,t-3-dimethyl-r-2,c-6-diphenylpiperidin-4-one (1.4g), phenylisocyanate (1.1ml) and triethylamine (2ml) in anhydrous benzene (20ml) was stirred at room temperature for 7 hours. The precipitated ammonium salt was washed with water (40ml). The resulting pasty mass was purified by crystallization from benzene and pet-ether (60-80°C) in the ratio of 95 : 5.