organic compounds
2,4-Bis(4-ethoxyphenyl)-7-methyl-3-azabicyclo[3.3.1]nonan-9-one
aDepartment of Biomedicinal Chemistry, Inje University, Gimhae, Gyeongnam 621 749, Republic of Korea, and bDepartment of Chemistry, IIT Madras, Chennai 600 036, TamilNadu, India
*Correspondence e-mail: parthisivam@yahoo.co.in
The molecule of the title compound, C25H31NO3, exists in a twin-chair conformation with an equatorial orientation of the 4-ethoxyphenyl groups, as observed for its ortho isomer [Parthiban, Ramkumar, Park & Jeong (2011b), Acta Cryst. E67, o1475–o1476]. The methyl and 4-ethoxyphenyl groups are also equatorially oriented on the bicycle, as in the ortho analogue. In particular, although the cyclohexanone ring deviates from an ideal chair, the piperidone ring is closer to an ideal chair, whereas in the ortho isomer both rings are significantly puckered and deviate from ideal chairs. The 4-ethoxyphenyl groups on both sides of the secondary amine group are oriented at an angle of 26.11 (3)° with respect to each other, but the 2-ethoxyphenyl groups in the ortho isomer are oriented by less than half this [12.41 (4)°]. In contrast to the absence of any significant interactions in the crystal packing of the ortho isomer, the title compound features N—H⋯O interactions, linking the molecules along the b axis.
Related literature
For the synthesis and stereochemistry of 3-azabicyclo[3.3.1] nonan-9-ones, see: Park et al. (2011). For the biological activities of 3-azabicyclo[3.3.1]nonan-9-ones, see: Barker et al. (2005); Parthiban et al. (2009, 2010a,b,2011a). For a related structure, see: Parthiban et al. (2011b). For ring-puckering parameters, see: Cremer & Pople (1975); Nardelli (1983).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2004); cell APEX2 and SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus and XPREP (Bruker, 2004); 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.
Supporting information
10.1107/S1600536812006563/bq2338sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812006563/bq2338Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812006563/bq2338Isup3.cml
The 2,4-bis(4-ethoxyphenyl)-7-methyl-3-azabicyclo[3.3.1]nonan-9-one was synthesized by a modified and an optimized Mannich condensation in one-pot, using 4-ethoxybenzaldehyde (0.1 mol, 15.018 g/13.91 ml), cyclohexanone (0.05 mol, 5.61 g/6.14 ml) and ammonium acetate (0.075 mol, 5.78 g) in a 50 ml of absolute ethanol (Park et al., 2001). The mixture was gently warmed on a hot plate at 303–308 K (30–35° C) with moderate stirring till the complete consumption of the starting materials, which was monitored by TLC. At the end, the crude azabicyclic ketone was separated by filtration and gently washed with 1:5 cold ethanol–ether mixture. X-ray diffraction quality crystals of the title compound were obtained by slow evaporation from ethanol.
The nitrogen H atom and C6 H atoms were located by difference Fourier map and refined isotropically. Other H atoms were fixed geometrically and allowed to ride on the parent C atoms with aromatic C—H = 0.93 Å, aliphatic C—H = 0.98 Å and methylene C—H = 0.97 Å. The displacement parameters were set for phenyl, methylene and aliphatic H atoms at Uiso(H) = 1.2Ueq(C) and for methyl H atoms at Uiso(H) = 1.5Ueq(C). Because of the meaningless of the
parameter, 400 Friedel-pairs were merged before final refinementData collection: APEX2 (Bruker, 2004); cell
APEX2 and SAINT (Bruker, 2004); data reduction: SAINT-Plus and XPREP (Bruker, 2004); 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 (Sheldrick, 2008).C25H31NO3 | F(000) = 424 |
Mr = 393.51 | Dx = 1.206 Mg m−3 |
Orthorhombic, Pmn21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac -2 | Cell parameters from 1281 reflections |
a = 19.329 (4) Å | θ = 2.5–22.3° |
b = 6.7967 (12) Å | µ = 0.08 mm−1 |
c = 8.2501 (16) Å | T = 298 K |
V = 1083.8 (4) Å3 | Block, colourless |
Z = 2 | 0.35 × 0.28 × 0.10 mm |
Bruker APEXII CCD area-detector diffractometer | 1165 independent reflections |
Radiation source: fine-focus sealed tube | 950 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.015 |
ϕ and ω scans | θmax = 26.0°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS; Bruker, 2004) | h = 0→23 |
Tmin = 0.973, Tmax = 0.992 | k = 0→8 |
1565 measured reflections | l = −7→10 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.037 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.094 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0502P)2 + 0.0596P] where P = (Fo2 + 2Fc2)/3 |
1165 reflections | (Δ/σ)max < 0.001 |
150 parameters | Δρmax = 0.12 e Å−3 |
4 restraints | Δρmin = −0.16 e Å−3 |
C25H31NO3 | V = 1083.8 (4) Å3 |
Mr = 393.51 | Z = 2 |
Orthorhombic, Pmn21 | Mo Kα radiation |
a = 19.329 (4) Å | µ = 0.08 mm−1 |
b = 6.7967 (12) Å | T = 298 K |
c = 8.2501 (16) Å | 0.35 × 0.28 × 0.10 mm |
Bruker APEXII CCD area-detector diffractometer | 1165 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2004) | 950 reflections with I > 2σ(I) |
Tmin = 0.973, Tmax = 0.992 | Rint = 0.015 |
1565 measured reflections |
R[F2 > 2σ(F2)] = 0.037 | 4 restraints |
wR(F2) = 0.094 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Δρmax = 0.12 e Å−3 |
1165 reflections | Δρmin = −0.16 e Å−3 |
150 parameters |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.06340 (12) | 0.4381 (3) | 0.8529 (3) | 0.0363 (6) | |
H1 | 0.0632 | 0.4085 | 0.7366 | 0.044* | |
C2 | 0.06391 (13) | 0.2389 (3) | 0.9456 (3) | 0.0389 (6) | |
H2 | 0.1044 | 0.1628 | 0.9112 | 0.047* | |
C3 | 0.0000 | 0.1332 (5) | 0.8932 (5) | 0.0415 (8) | |
C4 | 0.06491 (14) | 0.2575 (4) | 1.1304 (3) | 0.0477 (7) | |
H4A | 0.0714 | 0.1276 | 1.1767 | 0.057* | |
H4B | 0.1044 | 0.3370 | 1.1615 | 0.057* | |
C5 | 0.0000 | 0.3480 (6) | 1.2034 (4) | 0.0489 (10) | |
H5 | 0.0000 | 0.4887 | 1.1772 | 0.059* | |
C6 | 0.0000 | 0.3276 (10) | 1.3882 (6) | 0.0786 (15) | |
C7 | 0.12754 (11) | 0.5559 (3) | 0.8882 (3) | 0.0349 (6) | |
C8 | 0.12963 (12) | 0.7124 (4) | 0.9938 (3) | 0.0397 (6) | |
H8 | 0.0895 | 0.7477 | 1.0489 | 0.048* | |
C9 | 0.18980 (12) | 0.8191 (4) | 1.0205 (3) | 0.0434 (6) | |
H9 | 0.1898 | 0.9248 | 1.0921 | 0.052* | |
C10 | 0.24949 (12) | 0.7671 (4) | 0.9402 (3) | 0.0415 (6) | |
C11 | 0.24911 (14) | 0.6067 (4) | 0.8392 (4) | 0.0517 (8) | |
H11 | 0.2898 | 0.5676 | 0.7885 | 0.062* | |
C12 | 0.18887 (13) | 0.5027 (4) | 0.8122 (4) | 0.0463 (6) | |
H12 | 0.1893 | 0.3956 | 0.7421 | 0.056* | |
C13 | 0.31170 (14) | 1.0533 (4) | 1.0305 (4) | 0.0610 (8) | |
H13A | 0.3057 | 1.0357 | 1.1463 | 0.073* | |
H13B | 0.2741 | 1.1343 | 0.9905 | 0.073* | |
C14 | 0.37939 (15) | 1.1511 (5) | 0.9972 (5) | 0.0731 (10) | |
H14A | 0.4162 | 1.0730 | 1.0414 | 0.110* | |
H14B | 0.3798 | 1.2790 | 1.0466 | 0.110* | |
H14C | 0.3856 | 1.1643 | 0.8823 | 0.110* | |
N1 | 0.0000 | 0.5455 (4) | 0.8897 (4) | 0.0361 (7) | |
O1 | 0.0000 | −0.0133 (4) | 0.8084 (4) | 0.0603 (8) | |
O2 | 0.31106 (9) | 0.8665 (3) | 0.9511 (3) | 0.0599 (6) | |
H1A | 0.0000 | 0.656 (3) | 0.840 (4) | 0.033 (10)* | |
H6A | −0.0436 (13) | 0.385 (5) | 1.427 (5) | 0.091 (12)* | |
H6B | 0.0000 | 0.189 (4) | 1.421 (7) | 0.089 (18)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0373 (14) | 0.0399 (13) | 0.0318 (12) | 0.0017 (10) | 0.0031 (10) | 0.0015 (11) |
C2 | 0.0344 (13) | 0.0350 (12) | 0.0471 (13) | 0.0070 (10) | 0.0024 (12) | 0.0050 (13) |
C3 | 0.050 (2) | 0.0315 (18) | 0.0426 (18) | 0.000 | 0.000 | 0.0048 (19) |
C4 | 0.0452 (17) | 0.0520 (15) | 0.0459 (14) | −0.0029 (12) | −0.0086 (12) | 0.0147 (14) |
C5 | 0.057 (3) | 0.053 (2) | 0.0369 (18) | 0.000 | 0.000 | 0.005 (2) |
C6 | 0.095 (4) | 0.103 (4) | 0.038 (2) | 0.000 | 0.000 | 0.008 (3) |
C7 | 0.0319 (13) | 0.0376 (13) | 0.0353 (12) | 0.0030 (10) | 0.0060 (10) | 0.0055 (12) |
C8 | 0.0310 (12) | 0.0453 (13) | 0.0428 (13) | 0.0050 (10) | 0.0055 (10) | −0.0038 (13) |
C9 | 0.0406 (14) | 0.0435 (13) | 0.0461 (13) | 0.0031 (11) | 0.0023 (12) | −0.0054 (14) |
C10 | 0.0334 (13) | 0.0414 (13) | 0.0498 (13) | −0.0003 (11) | 0.0052 (12) | −0.0004 (13) |
C11 | 0.0369 (15) | 0.0466 (15) | 0.0717 (19) | 0.0010 (12) | 0.0197 (14) | −0.0083 (16) |
C12 | 0.0442 (16) | 0.0390 (13) | 0.0556 (14) | 0.0017 (12) | 0.0131 (12) | −0.0078 (14) |
C13 | 0.0543 (18) | 0.0615 (18) | 0.0672 (19) | −0.0074 (13) | 0.0053 (15) | −0.0171 (18) |
C14 | 0.065 (2) | 0.076 (2) | 0.079 (2) | −0.0226 (17) | 0.0056 (18) | −0.021 (2) |
N1 | 0.0317 (16) | 0.0324 (16) | 0.0441 (16) | 0.000 | 0.000 | 0.0075 (14) |
O1 | 0.073 (2) | 0.0366 (14) | 0.0713 (18) | 0.000 | 0.000 | −0.0071 (16) |
O2 | 0.0388 (10) | 0.0547 (11) | 0.0862 (14) | −0.0084 (9) | 0.0101 (10) | −0.0158 (13) |
C1—N1 | 1.458 (3) | C8—C9 | 1.388 (3) |
C1—C7 | 1.504 (3) | C8—H8 | 0.9300 |
C1—C2 | 1.555 (3) | C9—C10 | 1.376 (3) |
C1—H1 | 0.9800 | C9—H9 | 0.9300 |
C2—C3 | 1.493 (3) | C10—O2 | 1.371 (3) |
C2—C4 | 1.530 (4) | C10—C11 | 1.373 (4) |
C2—H2 | 0.9800 | C11—C12 | 1.380 (3) |
C3—O1 | 1.216 (4) | C11—H11 | 0.9300 |
C3—C2i | 1.493 (3) | C12—H12 | 0.9300 |
C4—C5 | 1.521 (4) | C13—O2 | 1.429 (3) |
C4—H4A | 0.9700 | C13—C14 | 1.493 (4) |
C4—H4B | 0.9700 | C13—H13A | 0.9700 |
C5—C4i | 1.521 (4) | C13—H13B | 0.9700 |
C5—C6 | 1.531 (6) | C14—H14A | 0.9600 |
C5—H5 | 0.9800 | C14—H14B | 0.9600 |
C6—H6A | 0.980 (18) | C14—H14C | 0.9600 |
C6—H6B | 0.98 (2) | N1—C1i | 1.458 (3) |
C7—C8 | 1.375 (3) | N1—H1A | 0.855 (18) |
C7—C12 | 1.389 (3) | ||
N1—C1—C7 | 112.68 (19) | C12—C7—C1 | 118.5 (2) |
N1—C1—C2 | 109.8 (2) | C7—C8—C9 | 122.0 (2) |
C7—C1—C2 | 111.28 (19) | C7—C8—H8 | 119.0 |
N1—C1—H1 | 107.6 | C9—C8—H8 | 119.0 |
C7—C1—H1 | 107.6 | C10—C9—C8 | 119.4 (2) |
C2—C1—H1 | 107.6 | C10—C9—H9 | 120.3 |
C3—C2—C4 | 109.8 (2) | C8—C9—H9 | 120.3 |
C3—C2—C1 | 105.8 (2) | O2—C10—C11 | 115.8 (2) |
C4—C2—C1 | 114.7 (2) | O2—C10—C9 | 124.7 (2) |
C3—C2—H2 | 108.8 | C11—C10—C9 | 119.5 (2) |
C4—C2—H2 | 108.8 | C10—C11—C12 | 120.6 (2) |
C1—C2—H2 | 108.8 | C10—C11—H11 | 119.7 |
O1—C3—C2 | 124.08 (16) | C12—C11—H11 | 119.7 |
O1—C3—C2i | 124.08 (16) | C11—C12—C7 | 120.9 (3) |
C2—C3—C2i | 111.6 (3) | C11—C12—H12 | 119.5 |
C5—C4—C2 | 114.6 (2) | C7—C12—H12 | 119.5 |
C5—C4—H4A | 108.6 | O2—C13—C14 | 108.6 (2) |
C2—C4—H4A | 108.6 | O2—C13—H13A | 110.0 |
C5—C4—H4B | 108.6 | C14—C13—H13A | 110.0 |
C2—C4—H4B | 108.6 | O2—C13—H13B | 110.0 |
H4A—C4—H4B | 107.6 | C14—C13—H13B | 110.0 |
C4i—C5—C4 | 111.1 (3) | H13A—C13—H13B | 108.3 |
C4i—C5—C6 | 110.9 (2) | C13—C14—H14A | 109.5 |
C4—C5—C6 | 110.9 (2) | C13—C14—H14B | 109.5 |
C4i—C5—H5 | 107.9 | H14A—C14—H14B | 109.5 |
C4—C5—H5 | 107.9 | C13—C14—H14C | 109.5 |
C6—C5—H5 | 107.9 | H14A—C14—H14C | 109.5 |
C5—C6—H6A | 107 (3) | H14B—C14—H14C | 109.5 |
C5—C6—H6B | 111 (4) | C1i—N1—C1 | 114.3 (3) |
H6A—C6—H6B | 107 (3) | C1i—N1—H1A | 109.9 (10) |
C8—C7—C12 | 117.5 (2) | C1—N1—H1A | 109.9 (10) |
C8—C7—C1 | 124.0 (2) | C10—O2—C13 | 118.37 (19) |
N1—C1—C2—C3 | 57.5 (3) | C12—C7—C8—C9 | 2.2 (4) |
C7—C1—C2—C3 | −177.0 (2) | C1—C7—C8—C9 | −178.9 (2) |
N1—C1—C2—C4 | −63.6 (3) | C7—C8—C9—C10 | −0.4 (4) |
C7—C1—C2—C4 | 61.9 (3) | C8—C9—C10—O2 | 176.9 (2) |
C4—C2—C3—O1 | −125.3 (4) | C8—C9—C10—C11 | −2.1 (4) |
C1—C2—C3—O1 | 110.4 (4) | O2—C10—C11—C12 | −176.3 (3) |
C4—C2—C3—C2i | 59.6 (4) | C9—C10—C11—C12 | 2.8 (4) |
C1—C2—C3—C2i | −64.7 (3) | C10—C11—C12—C7 | −1.0 (4) |
C3—C2—C4—C5 | −53.1 (3) | C8—C7—C12—C11 | −1.5 (4) |
C1—C2—C4—C5 | 65.9 (3) | C1—C7—C12—C11 | 179.5 (2) |
C2—C4—C5—C4i | 46.1 (4) | C7—C1—N1—C1i | 178.43 (16) |
C2—C4—C5—C6 | 170.0 (3) | C2—C1—N1—C1i | −56.9 (3) |
N1—C1—C7—C8 | 22.0 (3) | C11—C10—O2—C13 | 169.0 (3) |
C2—C1—C7—C8 | −101.9 (3) | C9—C10—O2—C13 | −10.0 (4) |
N1—C1—C7—C12 | −159.1 (2) | C14—C13—O2—C10 | −168.2 (3) |
C2—C1—C7—C12 | 77.1 (3) |
Symmetry code: (i) −x, y, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O1ii | 0.86 (2) | 2.26 (2) | 3.073 (4) | 158 (3) |
Symmetry code: (ii) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | C25H31NO3 |
Mr | 393.51 |
Crystal system, space group | Orthorhombic, Pmn21 |
Temperature (K) | 298 |
a, b, c (Å) | 19.329 (4), 6.7967 (12), 8.2501 (16) |
V (Å3) | 1083.8 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.35 × 0.28 × 0.10 |
Data collection | |
Diffractometer | Bruker APEXII CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2004) |
Tmin, Tmax | 0.973, 0.992 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1565, 1165, 950 |
Rint | 0.015 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.094, 1.05 |
No. of reflections | 1165 |
No. of parameters | 150 |
No. of restraints | 4 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.12, −0.16 |
Computer programs: APEX2 (Bruker, 2004), APEX2 and SAINT (Bruker, 2004), SAINT-Plus and XPREP (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O1i | 0.855 (18) | 2.26 (2) | 3.073 (4) | 158 (3) |
Symmetry code: (i) x, y+1, z. |
Acknowledgements
This research was supported by the International Research Foundation of Korea. The authors acknowledge the Department of Chemistry, IIT Madras, for the X-ray data collection.
References
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The 3-azabicyclononane nucleus is an important class of pharmacophore due to its broad-spectrum of biological actions ranging from antibacterial to anticancer (Barker et al., 2005; Parthiban et al., 2009, 2010a,b, 2011a). Owing to their broad-spectrum of biological actions, synthesis as well as isolaton of new molecules from the natural products, and their stereochemical analysis are considered as important in the field of medicinal chemistry. Hence, we synthesized the title compound by a modified and an optimized successive double Mannich condensation. Thus the obtained crystal was undertaken for this study to explore its stereochemistry in the solid-state.
The crystallographic parameters viz. torsion angles, asymmetry parameters and ring puckering parameters calculated for the title compound show that the piperidone ring adopts a near ideal chair conformation, according to Cremer & Pople and Nardelli (Fig. 1). The total puckering amplitude, QT is 0.607 (6) Å, the phase angle θ is 7.7 (6)° and ϕ is 180.0° (Cremer & Pople, 1975). The smallest displacement asymmetry parameters q2 and q3 are 0.081 (6) Å and 0.601 (6) Å, respectively (Nardelli, 1983). On the other hand, the cyclohexane ring deviates from the ideal chair conformation by QT = 0.536 (6), θ = 170.2 (7)° and ϕ = 240.0° (Cremer & Pople, 1975) as well as Nardelli by q2 = 0.092 (7) and q3 = 0.528 (6)° (Nardelli, 1983). In its ortho isomer, that is, 2,4-bis(2-ethoxyphenyl)-7-methyl-3-azabicyclo[3.3.1]nonan-9-one (Parthiban et al., 2011b), both the piperidone and cyclohexanone rings deviated the ideal chair as follows (QT = 0.5889 (18), θ = 7.19 (18)° and QT = 0.554 (2), θ = 12.2 (2)°, respectively).
The aryl groups are orientated at an angle of 26.11 (3)° to each other. The center of symmetry passes through C6 C5 C3 N1 and O1. The torsion angle of C3—C2—C1—C7 and its mirror image is -176.7 (5)°. The angle with C&P plane normal of bonds C1—C7 as well as C1a—C7a and C5—C6 are 73.27 and 65.36 (2), respectively, conforms the equatorial disposition of the aryl and alkyl groups on the bicycle. Hence, the title compound C25H31NO3, exists in a double-chair conformation with an equatorial orientation of the 4-ethoxyphenyl groups on both sides of the secondary amino group on the heterocycle and exocyclic orientation of the methyl on the cyclohexane ring.
The crystal packing is stabilized by an intermolecular N—H···O interaction of 2.26 (2) Å (Table 1 and Fig. 2).