3-Nitroso-2,4,6,8-tetra­phenyl-3,7-diaza­bicyclo­[3.3.1]nonan-9-one

Sampath Natarajan; Rita Mathews

doi:10.1107/S1600536811022203

. 2011 Jun 18;67(Pt 7):o1686. doi: 10.1107/S1600536811022203

3-Nitroso-2,4,6,8-tetraphenyl-3,7-diazabicyclo[3.3.1]nonan-9-one

Sampath Natarajan ^a,^*, Rita Mathews ^a

PMCID: PMC3152129 PMID: 21837083

Abstract

In the title compound, C₃₁H₂₇N₃O₂, the two piperidine rings fused to each other each adopt a slightly distorted chair conformation. The phenyl rings on the N-unsubstituted piperidine ring occupy an equatorial position, while those on the N-nitroso-substituted piperidine ring are in axial positions. The NO group is approximately coplanar with the piperidine ring with a maximum deviation of 0.048 (4) Å. The dihedral angles between the mean planes of the axially and equatorially oriented phenyl rings are 27.7 (1) and 31.9 (1)°, respectively. Molecular packing is stabilized by weak intermolecular C—H⋯O and C—H⋯π interactions.

Related literature

For piperidine ring conformations, see: Hofer (1976 ▶); Ramalingam et al. (1979 ▶); Mulekar & Berlin (1989 ▶); Pandiarajan et al. (1991 ▶); Rogers & Woodbrey (1962 ▶). For related structures, see: Hemalatha & Nagarajan (2010 ▶); Sampath et al. (2005 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶). For the synthesis of the title compound, see: Noller & Baliah (1948 ▶).

Experimental

Crystal data

C₃₁H₂₇N₃O₂
M _r = 473.56
Monoclinic,
a = 18.723 (4) Å
b = 8.8319 (17) Å
c = 15.806 (3) Å
β = 104.728 (3)°
V = 2527.8 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 293 K
0.26 × 0.23 × 0.21 mm

Data collection

Bruker SMART APEX CCD diffractometer
19483 measured reflections
5385 independent reflections
3235 reflections with I > 2σ(I)
R _int = 0.056

Refinement

R[F ² > 2σ(F ²)] = 0.081
wR(F ²) = 0.187
S = 1.06
5385 reflections
334 parameters
H-atom parameters constrained
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.29 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: PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811022203/jj2089sup1.cif

e-67-o1686-sup1.cif^{(25.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811022203/jj2089Isup2.hkl

e-67-o1686-Isup2.hkl^{(258.4KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811022203/jj2089Isup3.cml

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

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

Cg1 is the centroid of the C31–C36 benzene ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C18—H18⋯O3	0.93	2.94	3.607 (1)	130
C20—H20⋯O1	0.93	2.79	3.622 (4)	150
C24—H24⋯O2	0.93	2.64	3.276 (5)	126
C36—H36⋯O3	0.93	2.80	3.415 (9)	125
C17—H17⋯O1ⁱ	0.93	2.66	3.311 (4)	128
C22—H22⋯O1ⁱⁱ	0.93	2.74	3.579 (5)	150
C32—H32⋯O2ⁱⁱⁱ	0.93	2.43	3.127 (6)	132
C34—H34⋯O3^iv	0.93	2.24	2.878 (1)	125
C29—H29⋯Cg1^v	0.93	2.87	3.677	146

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) .

supplementary crystallographic information

Comment

The piperidine ring system offers a wide variety of conformational flexibility such as chair, boat and twisted boat conformations (Hofer, 1976). However, both the chair and slightly distorted chair conformations are found to be the most favored (Ramalingam et al., 1979; Mulekar & Berlin, 1989). N-nitroso piperidine compounds have been shown to occupy both axial and equatorial positions with the mean plane of the N—NO₂ group being coplanar to the mean plane of the piperidine ring (Hemalatha & Nagarajan, 2010; Sampath et al., 2005). The phenyl rings tend to occupy equatorial positions when the N—NO₂ group orients itself perpendicular to the piperidine ring to avoid steric hindrance. π-electron delocalization on the N—N—O group, which restricts the free rotation of N—N bond, results in orientations that are planar (syn; Pandiarajan et al., 1991) or perpendicular (anti; Rogers & Woodbrey, 1962) with respect to the piperidine ring. In 2,6-diphenyl-3-methyl-N-nitrosopiperidin- 4-one (Hemalatha & Nagarajan, 2010) the nitroso group shows both syn and anti conformations while the piperidine ring displays a boat conformation which may influence the phenyl rings to occupy axial and equitorial positions with respect to the piperidine ring.

In the title compound both piperidine rings adopt a slightly distorted chair conformation (Cremer & Pople, 1975) with puckering parameters parameters Q, θ and φ of 0.538 (3) Å, 18.0 (3)°, 142.8 (1)° [N-substituted piperidine ring (N1/C2/C8/C9/C7/C6)] and 0.657 (2) Å, 173.2 (3)° and 51.0 (2)° [N-free piperidine ring (N4/C5/C7/C9/C8/C3)], respectively (Fig. 1). For an ideal chair θ has a value of 0 or 180°. In the N-substituted piperidine ring (N1/C2/C8/C9/C7/C6) the N atom displays sp² hybridization, as evidenced by sum of angles around the N1 atom being nearly equal to 360° [C2/N1/C6 = 122.0 (2)°, C2/N1/N2 = 123.2 (3)° and C6/N1/N2 = 114.8 (3)°]}.

Phenyl rings C13–C18 and C19–C24 are substituted axially in the N—NO₂ piperidine ring. Torsion angles for phenyl ring C13–C18 {C6/N1/C2/C13 = 79.7 (3)°; C9/C8/C2/C13 = -69.2 (3)°} and for phenyl ring C19–C24 [C2/N1/C6/C19 = -88.8 (3)°; C9/C7/C6/C19 = 84.1 (3)°}] support this observation. The dihedral angle between these phenyl rings is 27.7 (1)°. Phenyl rings C25–C30 and C31–C36 are oriented equatorially to the piperidine ring. Torsion angles for phenyl ring C25–C30 [C3/N4/C5/C25 = 172.9 (2)°, C9/C7/C5/C25 = -171.7 (2)°] and C31–C36 [C9/C8/C3/C31 = 178.8 (2)°, C5/N4/C3/C31 = -176.2 (2)°] support this observation. The dihedral angle between these phenyl rings is 31.9 (1)°. Molecular packing is stabilized by weak C—H···O intra and intermolecular interactions and weak C—H···π intermolecular interactions (Table 1, Fig. 2).

Experimental

Noller & Baliah (1948) developed a novel method to synthesize piperidin-4-one derivatives by the Mannich condensation reaction using respective aldehydes and ketones with ammonium acetate in the ratio of [2:1:1], respectively. The title compound was synthesized using benzaldehyde (0.2 M), acetone (0.1) and ammonium acetate (0.1M) added to pure ethanol and heated on a hot plate up to the boiling range. The resulting product of diazabicyclic[3.3.1]nonan-9-one was separated out and treated with an equimolar (1:1) quantity of NaNO₂/HCl/80% ethanol and kept at 80° C for 4 h with vigorous stirring. The resuling title compound was separated out and crystals were grown using acetonitrile as the solvent.