2,4-Bis(3-bromo­phen­yl)-3-aza­bicyclo­[3.3.1]nonan-9-one

Abstract

The complete mol­ecule of the title compound, C₂₀H₁₉Br₂NO, is generated by crystallographic mirror symmetry, with two C, one O and one N atom lying on the mirror plane. The compound exists in a twin-chair conformation with equatorial dispositions of the 3-bromo­phenyl groups [dihedral angle between rings = 27.37 (3)°]. The packing is stabilized by weak N—H⋯O and C—H⋯O inter­actions.

Related literature

For background, see: Barker et al. (2005 ▶); Jeyaraman & Avila (1981 ▶); Padegimas & Kovacic (1972 ▶); Smith-Verdier et al. (1983 ▶). For a similiar structure, see: Parthiban et al. (2008 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶); Web & Becker (1967 ▶).

Experimental

Crystal data

• C₂₀H₁₉Br₂NO

• M _r = 449.18

• Orthorhombic,

• a = 7.1595 (6) Å

• b = 24.5891 (19) Å

• c = 10.2598 (6) Å

• V = 1806.2 (2) ų

• Z = 4

• Mo Kα radiation

• μ = 4.49 mm⁻¹

• T = 298 (2) K

• 0.34 × 0.25 × 0.18 mm

Data collection

• Bruker SMART CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 1999 ▶) T _min = 0.310, T _max = 0.498 (expected range = 0.277–0.445)

• 12758 measured reflections

• 2286 independent reflections

• 1554 reflections with I > 2σ(I)

• R _int = 0.035

Refinement

• R[F ² > 2σ(F ²)] = 0.042

• wR(F ²) = 0.103

• S = 1.05

• 2286 reflections

• 118 parameters

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.84 e Å⁻³

• Δρ_min = −0.71 e Å⁻³

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT (Bruker, 1999 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

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
N1—H1A⋯O1i	0.87 (5)	2.41 (5)	3.168 (5)	145 (4)
C1—H1⋯O1ii	0.98	2.54	3.361 (4)	142

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

Azabicyclic ketones are an important class of heterocycles due to their broad-spectrum biological activities (Jeyaraman & Avila, 1981; Barker et al., 2005). Owing to the diverse possibilities in conformations, viz., chair-chair (Parthiban et al., 2008), chair-boat (Smith-Verdier et al., 1983) and boat-boat (Padegimas & Kovacic, 1972) for the azabicycle, the present crystal study was undertaken to explore the conformation, stereochemistry and bondings in the title compound, (I).

The piperidine ring in (I) adopts an ideal chair conformation with the deviation of ring atoms C3 and N1 from the C1/C2/C2ⁱ/C1ⁱ (i = x, 3/2-y, z) plane being 0.686 (3) and -0.702 (3) Å, respectively. The q2 and q3 values are 0.010 (3) and -0.617 (3)Å and the total puckering amplitude, Q_T = 0.617 (3)Å and θ = 180.0 (3)° (Cremer & Pople, 1975; Web & Becker, 1967).

The cyclohexane ring deviate from the ideal chair conformation by the deviation of ring atoms C3 and C5 from the C2/C4/C4ⁱ/C2ⁱ plane by -0.725 (4) and 0.525 (3)Å, respectively. For the cyclohexane, the q2 and q3 parameters are 0.150 (4) and 0.543 (4)Å respectively. The total puckering amplitude, Q_T = 0.563 (3)Å and θ =15.6 (4)°. Hence, the title compound, exists in a twin-chair conformation with equatorial orientations of the 3-bromophenyl groups on the heterocycle, which are orientated at an angle of 27.37 (3)° to each other. The torsion angles of C3—C2—C1—C6 and its mirror plane C3—C2ⁱ—C1ⁱ—C6ⁱ is 174.45 (4)°. The packing is stabilized by weak N—H···O and C—H···O bonds (Table 1).

Experimental

0.1 mol of meta Bromobenzaldehyde and 0.05 mol of cyclohexanone were simultaneously added to a warm solution of 0.075 mol ammonium acetate in 50 ml of absolute ethanol. The mixture was gently warmed on a hot plate till the yellow colour formed during the mixing of the reactants and cooled to room temperature. Then 50 ml of ether was added and allowed to stir over night at warm condition (303–305 K). At the end, the crude azabicyclic ketone was separated by filtration and washed with 1:5 v/v ethanol-ether mixture until the solid become colourless. Colourless blocks of (I) were recrystallised from acetone.

Refinement

The nitrogen-bound H atom was located in a difference map and refined isotropically. The other hydrogen atoms were fixed geometrically (C—H = 0.93–0.98Å) and refined as riding with U_iso(H) = 1.2U_eq(C).

Figures

Fig. 1.

The molecular structure of (I) with non-hydrogen atoms represented as 30% probability ellipsoids.

Fig. 2.

Packing diagram with N—H···O (blue) and C—H···O (red) interactions.

Crystal data

C20H19Br2NO	F000 = 896
Mr = 449.18	Dx = 1.652 Mg m−3
Orthorhombic, Pnma	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 3647 reflections
a = 7.1595 (6) Å	θ = 3.2–23.5º
b = 24.5891 (19) Å	µ = 4.49 mm−1
c = 10.2598 (6) Å	T = 298 (2) K
V = 1806.2 (2) Å3	Block, colourless
Z = 4	0.34 × 0.25 × 0.18 mm

Data collection

Bruker SMART CCD diffractometer	2286 independent reflections
Radiation source: fine-focus sealed tube	1554 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.035
T = 298(2) K	θmax = 28.9º
ω scans	θmin = 2.2º
Absorption correction: Multi-scan(SADABS; Bruker, 1999)	h = −9→9
Tmin = 0.310, Tmax = 0.498	k = −33→33
12758 measured reflections	l = −13→9

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.042	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.103	w = 1/[σ2(Fo2) + (0.0338P)2 + 2.5194P] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max < 0.001
2286 reflections	Δρmax = 0.84 e Å−3
118 parameters	Δρmin = −0.71 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

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 takeninto account individually in the estimation of e.s.d.'s in distances, anglesand torsion angles; correlations between e.s.d.'s in cell parameters are onlyused 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 F2 against ALL reflections. The weighted R-factor wR andgoodness of fit S are based on F2, conventional R-factors R are basedon F, with F set to zero for negative F2. The threshold expression ofF2 > σ(F2) is used only for calculating R-factors(gt) etc. and isnot relevant to the choice of reflections for refinement. R-factors basedon F2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Br1	0.06375 (6)	0.580496 (16)	0.86233 (5)	0.07173 (19)
C1	0.5903 (4)	0.70119 (11)	1.1050 (3)	0.0328 (6)
H1	0.6284	0.7040	1.1965	0.039*
C2	0.7711 (4)	0.69950 (12)	1.0210 (3)	0.0353 (6)
H2	0.8451	0.6677	1.0462	0.042*
C3	0.8806 (6)	0.7500	1.0506 (4)	0.0332 (9)
C4	0.7389 (4)	0.69827 (13)	0.8727 (3)	0.0401 (7)
H4A	0.8577	0.6919	0.8298	0.048*
H4B	0.6577	0.6679	0.8521	0.048*
C5	0.6529 (6)	0.7500	0.8173 (4)	0.0418 (10)
H5A	0.6685	0.7500	0.7234	0.050*
H5B	0.5200	0.7500	0.8356	0.050*
C6	0.4822 (4)	0.64879 (11)	1.0899 (3)	0.0350 (6)
C7	0.3394 (4)	0.64162 (11)	1.0003 (3)	0.0376 (7)
H7	0.2983	0.6707	0.9498	0.045*
C8	0.2582 (4)	0.59064 (12)	0.9868 (3)	0.0431 (8)
C9	0.3157 (5)	0.54686 (12)	1.0597 (4)	0.0541 (9)
H9	0.2610	0.5129	1.0488	0.065*
C10	0.4556 (6)	0.55456 (15)	1.1489 (4)	0.0621 (11)
H10	0.4955	0.5254	1.1996	0.074*
C11	0.5382 (5)	0.60472 (14)	1.1647 (4)	0.0511 (9)
H11	0.6324	0.6091	1.2262	0.061*
N1	0.4821 (5)	0.7500	1.0736 (3)	0.0303 (7)
O1	1.0403 (4)	0.7500	1.0910 (3)	0.0493 (8)
H1A	0.376 (6)	0.7500	1.115 (4)	0.033 (12)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.0813 (3)	0.0450 (2)	0.0889 (4)	−0.01841 (19)	−0.0190 (2)	−0.0091 (2)
C1	0.0371 (15)	0.0305 (14)	0.0308 (16)	0.0038 (12)	0.0021 (12)	0.0031 (12)
C2	0.0324 (15)	0.0331 (14)	0.0404 (16)	0.0064 (12)	0.0004 (12)	0.0023 (13)
C3	0.030 (2)	0.045 (2)	0.025 (2)	0.000	0.0024 (16)	0.000
C4	0.0390 (16)	0.0432 (17)	0.0382 (17)	−0.0025 (13)	0.0047 (13)	−0.0087 (14)
C5	0.039 (2)	0.058 (3)	0.028 (2)	0.000	0.0000 (19)	0.000
C6	0.0401 (16)	0.0260 (13)	0.0387 (16)	0.0037 (12)	0.0105 (13)	0.0017 (12)
C7	0.0434 (17)	0.0247 (14)	0.0447 (18)	0.0012 (12)	0.0046 (14)	0.0023 (13)
C8	0.0480 (18)	0.0284 (15)	0.0531 (19)	−0.0031 (13)	0.0108 (16)	−0.0070 (14)
C9	0.066 (2)	0.0213 (14)	0.075 (3)	−0.0032 (15)	0.016 (2)	0.0009 (16)
C10	0.071 (3)	0.0344 (18)	0.081 (3)	0.0068 (17)	−0.001 (2)	0.0204 (19)
C11	0.054 (2)	0.0394 (18)	0.060 (2)	0.0025 (15)	−0.0034 (17)	0.0154 (16)
N1	0.0286 (17)	0.0237 (16)	0.0385 (19)	0.000	0.0056 (15)	0.000
O1	0.0322 (17)	0.064 (2)	0.0520 (19)	0.000	−0.0072 (14)	0.000

Geometric parameters (Å, °)

Br1—C8	1.905 (3)	C5—H5A	0.9700
C1—N1	1.464 (3)	C5—H5B	0.9700
C1—C6	1.511 (4)	C6—C7	1.386 (4)
C1—C2	1.555 (4)	C6—C11	1.387 (4)
C1—H1	0.9800	C7—C8	1.389 (4)
C2—C3	1.500 (4)	C7—H7	0.9300
C2—C4	1.540 (4)	C8—C9	1.374 (5)
C2—H2	0.9800	C9—C10	1.369 (5)
C3—O1	1.216 (5)	C9—H9	0.9300
C3—C2i	1.500 (4)	C10—C11	1.377 (5)
C4—C5	1.523 (4)	C10—H10	0.9300
C4—H4A	0.9700	C11—H11	0.9300
C4—H4B	0.9700	N1—C1i	1.464 (3)
C5—C4i	1.523 (4)	N1—H1A	0.87 (5)
N1—C1—C6	113.9 (2)	C4i—C5—H5B	108.9
N1—C1—C2	109.9 (2)	C4—C5—H5B	108.9
C6—C1—C2	110.3 (2)	H5A—C5—H5B	107.7
N1—C1—H1	107.5	C7—C6—C11	118.8 (3)
C6—C1—H1	107.5	C7—C6—C1	123.7 (3)
C2—C1—H1	107.5	C11—C6—C1	117.4 (3)
C3—C2—C4	107.1 (3)	C6—C7—C8	119.3 (3)
C3—C2—C1	107.5 (2)	C6—C7—H7	120.3
C4—C2—C1	115.1 (2)	C8—C7—H7	120.3
C3—C2—H2	109.0	C9—C8—C7	121.8 (3)
C4—C2—H2	109.0	C9—C8—Br1	118.8 (2)
C1—C2—H2	109.0	C7—C8—Br1	119.4 (2)
O1—C3—C2	124.10 (16)	C10—C9—C8	118.3 (3)
O1—C3—C2i	124.10 (17)	C10—C9—H9	120.8
C2—C3—C2i	111.8 (3)	C8—C9—H9	120.8
C5—C4—C2	114.4 (3)	C9—C10—C11	121.1 (3)
C5—C4—H4A	108.7	C9—C10—H10	119.5
C2—C4—H4A	108.7	C11—C10—H10	119.4
C5—C4—H4B	108.7	C10—C11—C6	120.7 (3)
C2—C4—H4B	108.7	C10—C11—H11	119.7
H4A—C4—H4B	107.6	C6—C11—H11	119.7
C4i—C5—C4	113.3 (4)	C1i—N1—C1	110.1 (3)
C4i—C5—H5A	108.9	C1i—N1—H1A	110.7 (13)
C4—C5—H5A	108.9	C1—N1—H1A	110.7 (14)
N1—C1—C2—C3	59.2 (3)	C2—C1—C6—C11	82.1 (3)
C6—C1—C2—C3	−174.5 (2)	C11—C6—C7—C8	−0.8 (4)
N1—C1—C2—C4	−60.1 (3)	C1—C6—C7—C8	175.0 (3)
C6—C1—C2—C4	66.3 (3)	C6—C7—C8—C9	−0.1 (5)
C4—C2—C3—O1	−113.3 (4)	C6—C7—C8—Br1	−179.3 (2)
C1—C2—C3—O1	122.5 (4)	C7—C8—C9—C10	0.8 (5)
C4—C2—C3—C2i	65.3 (4)	Br1—C8—C9—C10	180.0 (3)
C1—C2—C3—C2i	−58.9 (4)	C8—C9—C10—C11	−0.5 (6)
C3—C2—C4—C5	−52.8 (3)	C9—C10—C11—C6	−0.4 (6)
C1—C2—C4—C5	66.7 (4)	C7—C6—C11—C10	1.1 (5)
C2—C4—C5—C4i	43.3 (5)	C1—C6—C11—C10	−175.0 (3)
N1—C1—C6—C7	30.3 (4)	C6—C1—N1—C1i	173.61 (18)
C2—C1—C6—C7	−93.7 (3)	C2—C1—N1—C1i	−62.1 (4)
N1—C1—C6—C11	−153.8 (3)

Symmetry codes: (i) x, −y+3/2, z.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1ii	0.87 (5)	2.41 (5)	3.168 (5)	145 (4)
C1—H1···O1iii	0.98	2.54	3.361 (4)	142

Symmetry codes: (ii) x−1, y, z; (iii) x−1/2, −y+3/2, −z+5/2.