organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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2,3,10,11-Tetra­meth­­oxy-6,7,14,15-tetra­hydro-6,14-methano­cyclo­octa­[1,2-b;5,6-b′]di­quinoline

aSchool of Chemistry, University of New South Wales, Sydney, Australia 2052
*Correspondence e-mail: r.bishop@unsw.edu.au

(Received 18 November 2007; accepted 20 November 2007; online 6 December 2007)

The racemic title compound, C27H26N2O4, crystallizes with its central carbon bridge on a twofold axis. It forms parallel chains of mol­ecules utilizing aryl offset face–face inter­actions with an interplanar distance of about 3.5 Å. These chains associate further by means of pairs of O—CH2—H⋯π (with H–ring distances ranging from 2.69 to 2.95 Å) and O—CH2—H⋯N motifs. The meth­oxy groups in this structure are coplanar with the aromatic rings to which they are attached. This is recognized as being common behaviour amongst aromatic meth­oxy compounds.

Related literature

Condensation of two equivalents of a 2-amino­benzaldehyde derivative with one of bicyclo­[3.3.1]nonane-2,6-dione provides a V-shaped diquinoline adduct by means of the Friedländer condensation (Cheng & Yan, 1982[Cheng, C.-C. & Yan, S.-J. (1982). Org. React. 28, 37-201.]). Substituted mol­ecules of this general structural type frequently act as lattice inclusion hosts (Bishop, 2006[Bishop, R. (2006). Crystal Engineering of Halogenated Heteroaromatic Clathrate Systems. In Frontiers in Crystal Engineering, ch. 5, pp. 91-116, edited by E. R. T. Tiekink & J. J. Vittal. Chichester: Wiley.]). For related literature, see: Allen (2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]); Desiraju & Gavezzotti (1989[Desiraju, G. R. & Gavezzotti, A. (1989). Acta Cryst. B45, 473-482.]); Marjo et al. (1997[Marjo, C. E., Scudder, M. L., Craig, D. C. & Bishop, R. (1997). J. Chem. Soc. Perkin Trans. 2, pp. 2099-2104.]); Pendrak et al. (1995[Pendrak, I., Wittrock, R. & Kingsbury, W. D. (1995). J. Org. Chem. 60, 2912-2915.]); Schaefer & Honig (1968[Schaefer, J. P. & Honig, L. M. (1968). J. Org. Chem. 33, 2655-2659.]).

[Scheme 1]

Experimental

Crystal data
  • C27H26N2O4

  • Mr = 442.5

  • Monoclinic, C 2/c

  • a = 14.137 (7) Å

  • b = 9.533 (6) Å

  • c = 16.551 (7) Å

  • β = 100.79 (3)°

  • V = 2191 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 294 K

  • 0.12 mm (radius)

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: none

  • 1999 measured reflections

  • 1926 independent reflections

  • 803 reflections with I > 2σ(I)

  • Rint = 0.062

  • 1 standard reflection frequency: 30 min intensity decay: none

Refinement
  • R[F2 > 2σ(F2)] = 0.050

  • wR(F2) = 0.053

  • S = 1.41

  • 803 reflections

  • 150 parameters

  • H-atom parameters not refined

  • Δρmax = 0.56 e Å−3

  • Δρmin = −0.48 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C14—H3C14⋯N1i 1.00 2.88 3.723 (5) 142
C14—H3C14⋯N1ii 1.00 2.96 3.348 (5) 104
Symmetry codes: (i) [-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]; (ii) [x-{\script{1\over 2}}, y-{\script{1\over 2}}, z].

Data collection: CAD-4 Software (Schagen et al., 1989[Schagen, J. D., Straver, L., van Meurs, F. & Williams, G. (1989). CAD-4 Software. Version 5.0. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: Local program; program(s) used to solve structure: SIR92 (Altomare et al., 1994[Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.]); program(s) used to refine structure: RAELS (Rae, 2000[Rae, A. D. (2000). RAELS. Australian National University, Canberra.]); molecular graphics: ORTEPII (Johnson, 1976[Johnson, C. K. (1976). ORTEPII, Oak Ridge National Laboratory, Tennessee, USA.]) and CrystalMaker (CrystalMaker, 2005[CrystalMaker (2005). CrystalMaker. CrystalMaker Software, Bicester, Oxfordshire, England. http://www.crystalmaker.co.uk.]); software used to prepare material for publication: Local programs.

Supporting information


Comment top

The asymmetric unit of the title compound, (1), contains half a molecule, with the central bridging carbon atom located on a twofold axis (Fig. 1).

Molecules of (1) form parallel chains along the ac diagonal (Fig. 2), associating by means of exo,exo-facial aryl offset face-face (OFF) interactions (Desiraju & Gavezzotti, 1989). The distance between the aromatic planes is about 3.5 Å. Complementary to the π···π interaction are a pair of associations between a methoxy group and a quinoline N atom (O—CH2—H···N; d = 2.88 Å), and a pair between an aliphatic methylene and a methoxy group (C—H···O—CH3, d = 2.84 Å). Adjacent chains interact in two ways: by means of a double centrosymmetric O—CH2—H···π interaction (utilizing the 3-methoxy group, with shortest C···C contacts of 3.57 and 3.82 Å) and an O—CH2—H···N interaction (utilizing the 10-methoxy group with C···N of 3.35 Å).

It is noteworthy that the methoxy groups in this structure are co-planar with the aromatic rings to which they are attached. The Cambridge Structural Database (Allen et al., 2002) reveals that this situation is commonplace amongst related compounds. The steric effects resulting from this co-planarity would be sufficient cause for the absence of centrosymmetric dimers utilizing the edge-edge aryl C—H···N supramolecular synthon which are found in the parent the non-methoxy diquinoline adduct (Marjo et al., 1997).

Related literature top

Condensation of two equivalents of a 2-aminobenzaldehyde derivative with one of bicyclo[3.3.1]nonane-2,6-dione provides a V-shaped diquinoline adduct by means of the Friedländer condensation (Cheng & Yan, 1982). Substituted molecules of this general structural type frequently act as lattice inclusion hosts (Bishop, 2006). For related literature, see: Allen (2002); Desiraju & Gavezzotti (1989); Marjo et al. (1997); Pendrak et al. (1995); Schaefer & Honig (1968).

Experimental top

2-Amino-4,5-dimethoxybenzaldehyde (Pendrak et al., 1995) (1.20 g, 6.62 mmol) and bicyclo[3.3.1]nonane-2,6-dione (Schaefer & Honig, 1968) (0.38 g, 2.50 mol) were dissolved in hot ethanol (20 ml) and a solution of sodium hydroxide (0.49 g, 12.25 mmol) in ethanol (10 ml) was added. The mixture was refluxed for 5 h, allowed to cool, then kept at 273 K for 5 h. Filtration gave the product 1 (0.51 g, 46%) of m.p. 548–549 K. 13C NMR (75.5 MHz, CDCl3) δ: 29.5 (CH2), 36.6 (CH), 38.2 (CH2), 56.2 (CH3), 56.4 (CH3), 104.6 (CH), 107.4 (CH), 123.3 (C), 126.8 (C), 134.7 (CH), 144.3 (C), 149.7 (C), 152.3 (C), 159.2 (C); 1H NMR (300 MHz, CDCl3) δ: 2.49 (br s, 2H), 3.25 & 3.32 (d, 2H, JAB 16.6 Hz), 3.42 & 3.49 (dd, 2H, JAB 16.6, JBX 5.3 Hz), 3.70 (d, 2H, J 2.6 Hz), 3.91 (s, 6H), 3.99 (s, 6H), 6.79 (s, 2H), 7.32 (s, 2H), 7.50 (s, 2H). X-ray quality crystals were obtained from ethyl acetate solution.

Refinement top

All hydrogen atoms were placed geometrically with C—H = 1.0 Å and Uiso(H) = Ueq(C).

Structure description top

The asymmetric unit of the title compound, (1), contains half a molecule, with the central bridging carbon atom located on a twofold axis (Fig. 1).

Molecules of (1) form parallel chains along the ac diagonal (Fig. 2), associating by means of exo,exo-facial aryl offset face-face (OFF) interactions (Desiraju & Gavezzotti, 1989). The distance between the aromatic planes is about 3.5 Å. Complementary to the π···π interaction are a pair of associations between a methoxy group and a quinoline N atom (O—CH2—H···N; d = 2.88 Å), and a pair between an aliphatic methylene and a methoxy group (C—H···O—CH3, d = 2.84 Å). Adjacent chains interact in two ways: by means of a double centrosymmetric O—CH2—H···π interaction (utilizing the 3-methoxy group, with shortest C···C contacts of 3.57 and 3.82 Å) and an O—CH2—H···N interaction (utilizing the 10-methoxy group with C···N of 3.35 Å).

It is noteworthy that the methoxy groups in this structure are co-planar with the aromatic rings to which they are attached. The Cambridge Structural Database (Allen et al., 2002) reveals that this situation is commonplace amongst related compounds. The steric effects resulting from this co-planarity would be sufficient cause for the absence of centrosymmetric dimers utilizing the edge-edge aryl C—H···N supramolecular synthon which are found in the parent the non-methoxy diquinoline adduct (Marjo et al., 1997).

Condensation of two equivalents of a 2-aminobenzaldehyde derivative with one of bicyclo[3.3.1]nonane-2,6-dione provides a V-shaped diquinoline adduct by means of the Friedländer condensation (Cheng & Yan, 1982). Substituted molecules of this general structural type frequently act as lattice inclusion hosts (Bishop, 2006). For related literature, see: Allen (2002); Desiraju & Gavezzotti (1989); Marjo et al. (1997); Pendrak et al. (1995); Schaefer & Honig (1968).

Computing details top

Data collection: CAD-4 Software (Schagen et al., 1989); cell refinement: CAD-4 Software (Schagen et al., 1989); data reduction: Local program; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: RAELS (Rae, 2000); molecular graphics: ORTEPII (Johnson, 1976) and CrystalMaker (CrystalMaker, 2005); software used to prepare material for publication: Local programs.

Figures top
[Figure 1] Fig. 1. Molecular structure of (1), with ellipsoids drawn at 30% probability level. Symmetry code: (i) 1 - x, y, 3/2 - z.
[Figure 2] Fig. 2. The chain of molecules of (1) with centrosymmetric OFF interactions between exo-surfaces of the aromatic wings. Adjacent molecules are of the opposite chirality.
[Figure 3] Fig. 3. The chain (top) interacts with adjacent chains in two ways: a double CH3···π interaction (pair of arrows at the bottom of the figure) and a CH3···N interaction (at the left of the figure).
2,3,10,11-Tetramethoxy-6,7,14,15-tetrahydro-6,14- methanocycloocta[1,2 - b;5,6-b']diquinoline top
Crystal data top
C27H26N2O4F(000) = 936.0
Mr = 442.5Dx = 1.34 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
a = 14.137 (7) ÅCell parameters from 11 reflections
b = 9.533 (6) Åθ = 10–11°
c = 16.551 (7) ŵ = 0.09 mm1
β = 100.79 (3)°T = 294 K
V = 2191 (2) Å3Irregular, colourless
Z = 40.12 mm (radius)
Data collection top
Enraf–Nonius CAD-4
diffractometer
θmax = 25°
ω–2θ scansh = 1616
1999 measured reflectionsk = 011
1926 independent reflectionsl = 019
803 reflections with I > 2σ(I)1 standard reflections every 30 min
Rint = 0.062 intensity decay: none
Refinement top
Refinement on F0 restraints
R[F2 > 2σ(F2)] = 0.050H-atom parameters not refined
wR(F2) = 0.053 w = 1/[σ2(F) + 0.0004F2]
S = 1.41(Δ/σ)max = 0.001
803 reflectionsΔρmax = 0.56 e Å3
150 parametersΔρmin = 0.48 e Å3
Crystal data top
C27H26N2O4V = 2191 (2) Å3
Mr = 442.5Z = 4
Monoclinic, C2/cMo Kα radiation
a = 14.137 (7) ŵ = 0.09 mm1
b = 9.533 (6) ÅT = 294 K
c = 16.551 (7) Å0.12 mm (radius)
β = 100.79 (3)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
Rint = 0.062
1999 measured reflections1 standard reflections every 30 min
1926 independent reflections intensity decay: none
803 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0500 restraints
wR(F2) = 0.053H-atom parameters not refined
S = 1.41Δρmax = 0.56 e Å3
803 reflectionsΔρmin = 0.48 e Å3
150 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
O10.3447 (2)0.0160 (3)0.3564 (2)0.059 (1)
O20.2109 (2)0.1040 (3)0.4273 (2)0.0559 (9)
N10.4643 (2)0.2977 (4)0.5789 (2)0.047 (1)
C10.5320 (4)0.4581 (5)0.6853 (3)0.055 (1)
C20.4554 (3)0.3525 (4)0.6509 (3)0.043 (1)
C30.3824 (3)0.3145 (5)0.6937 (3)0.045 (1)
C40.3736 (3)0.3841 (5)0.7746 (3)0.054 (1)
C50.50000.5529 (7)0.75000.062 (2)
C60.3986 (3)0.1982 (4)0.5451 (3)0.041 (1)
C70.4076 (3)0.1425 (5)0.4682 (2)0.042 (1)
C80.3440 (3)0.0430 (5)0.4314 (3)0.043 (1)
C90.2697 (3)0.0039 (5)0.4705 (3)0.042 (1)
C100.2596 (3)0.0469 (4)0.5446 (3)0.044 (1)
C110.3242 (3)0.1518 (5)0.5843 (2)0.042 (1)
C120.3174 (3)0.2147 (5)0.6597 (3)0.045 (1)
C130.4183 (4)0.0306 (6)0.3148 (3)0.076 (2)
C140.1350 (3)0.1571 (5)0.4654 (3)0.061 (1)
HC10.54530.51820.63920.055
H1C40.35770.31100.81320.054
H2C40.32070.45520.76400.054
H1C50.44510.61350.72350.0620.5
H2C50.55490.61350.77650.0620.5
HC70.46050.17550.44040.042
HC100.20680.01100.57170.044
HC120.26460.18630.68890.045
H1C130.41200.01910.26090.076
H2C130.41180.13400.30510.076
H3C130.48270.00980.34920.076
H1C140.09720.22870.42870.061
H2C140.16340.20140.51930.061
H3C140.09170.07830.47480.061
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.058 (2)0.066 (2)0.055 (2)0.016 (2)0.018 (2)0.021 (2)
O20.050 (2)0.057 (2)0.060 (2)0.014 (2)0.007 (2)0.003 (2)
N10.049 (2)0.050 (3)0.040 (2)0.007 (2)0.000 (2)0.002 (2)
C10.067 (3)0.050 (3)0.044 (3)0.007 (3)0.000 (3)0.004 (3)
C20.049 (3)0.039 (3)0.040 (3)0.005 (2)0.001 (2)0.004 (3)
C30.046 (3)0.047 (3)0.039 (3)0.009 (2)0.001 (2)0.007 (2)
C40.060 (3)0.060 (3)0.039 (3)0.020 (3)0.001 (2)0.006 (3)
C50.089 (6)0.045 (5)0.048 (4)0.00000.002 (4)0.0000
C60.039 (3)0.044 (3)0.038 (3)0.006 (2)0.002 (2)0.007 (2)
C70.036 (3)0.054 (3)0.039 (3)0.006 (2)0.010 (2)0.003 (3)
C80.042 (3)0.045 (3)0.040 (3)0.006 (2)0.007 (2)0.002 (3)
C90.036 (3)0.041 (3)0.047 (3)0.006 (2)0.001 (2)0.001 (3)
C100.038 (3)0.043 (3)0.051 (3)0.003 (2)0.006 (2)0.006 (2)
C110.042 (3)0.044 (3)0.040 (3)0.006 (3)0.007 (2)0.013 (3)
C120.043 (3)0.054 (3)0.038 (3)0.006 (3)0.007 (2)0.012 (2)
C130.074 (4)0.106 (5)0.056 (3)0.032 (3)0.029 (3)0.029 (3)
C140.050 (3)0.060 (3)0.072 (3)0.017 (3)0.004 (3)0.008 (3)
Geometric parameters (Å, º) top
O1—C81.365 (4)C6—C71.406 (5)
O1—C131.421 (5)C6—C111.407 (5)
O2—C91.375 (5)C7—C81.369 (5)
O2—C141.434 (4)C7—HC71.000
N1—C21.328 (5)C8—C91.406 (5)
N1—C61.371 (5)C9—C101.352 (5)
C1—C21.510 (6)C10—C111.428 (5)
C1—C4i1.545 (6)C10—HC101.000
C1—C51.532 (5)C11—C121.405 (5)
C1—HC11.000C12—HC121.000
C2—C31.405 (5)C13—H1C131.000
C3—C41.520 (5)C13—H2C131.000
C3—C121.368 (5)C13—H3C131.000
C4—H1C41.000C14—H1C141.000
C4—H2C41.000C14—H2C141.000
C5—H1C51.000C14—H3C141.000
C5—H2C51.000
C8—O1—C13116.3 (4)C6—C7—C8120.1 (4)
C9—O2—C14116.5 (3)C6—C7—HC7119.9
C2—N1—C6117.9 (4)C8—C7—HC7119.9
C2—C1—C4i111.0 (4)O1—C8—C7125.1 (4)
C2—C1—C5111.9 (4)O1—C8—C9114.9 (4)
C2—C1—HC1108.6C7—C8—C9120.0 (4)
C4i—C1—C5108.3 (3)O2—C9—C8114.4 (4)
C4i—C1—HC1108.6O2—C9—C10124.3 (4)
C5—C1—HC1108.6C8—C9—C10121.3 (4)
N1—C2—C1114.8 (4)C9—C10—C11120.0 (4)
N1—C2—C3123.6 (4)C9—C10—HC10120.0
C1—C2—C3121.6 (4)C11—C10—HC10120.0
C2—C3—C4121.3 (4)C6—C11—C10118.5 (4)
C2—C3—C12118.2 (4)C6—C11—C12117.2 (4)
C4—C3—C12120.5 (4)C10—C11—C12124.3 (4)
C1i—C4—C3111.8 (4)C3—C12—C11120.7 (4)
C1i—C4—H1C4108.9C3—C12—HC12119.7
C1i—C4—H2C4108.9C11—C12—HC12119.7
C3—C4—H1C4108.9O1—C13—H1C13109.5
C3—C4—H2C4108.9O1—C13—H2C13109.5
H1C4—C4—H2C4109.5O1—C13—H3C13109.5
C1—C5—C1i107.7 (5)H1C13—C13—H2C13109.5
C1—C5—H1C5109.9H1C13—C13—H3C13109.5
C1—C5—H2C5109.9H2C13—C13—H3C13109.5
C1i—C5—H1C5109.9O2—C14—H1C14109.5
C1i—C5—H2C5109.9O2—C14—H2C14109.5
H1C5—C5—H2C5109.5O2—C14—H3C14109.5
N1—C6—C7117.5 (4)H1C14—C14—H2C14109.5
N1—C6—C11122.5 (4)H1C14—C14—H3C14109.5
C7—C6—C11120.0 (4)H2C14—C14—H3C14109.5
Symmetry code: (i) x+1, y, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C14—H3C14···N1ii1.002.8823.723 (5)142
C14—H3C14···N1iii1.002.9583.348 (5)104
Symmetry codes: (ii) x+1/2, y+1/2, z+1; (iii) x1/2, y1/2, z.

Experimental details

Crystal data
Chemical formulaC27H26N2O4
Mr442.5
Crystal system, space groupMonoclinic, C2/c
Temperature (K)294
a, b, c (Å)14.137 (7), 9.533 (6), 16.551 (7)
β (°) 100.79 (3)
V3)2191 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.12 (radius)
Data collection
DiffractometerEnraf–Nonius CAD-4
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
1999, 1926, 803
Rint0.062
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.053, 1.41
No. of reflections803
No. of parameters150
H-atom treatmentH-atom parameters not refined
Δρmax, Δρmin (e Å3)0.56, 0.48

Computer programs: CAD-4 Software (Schagen et al., 1989), SIR92 (Altomare et al., 1994), RAELS (Rae, 2000), ORTEPII (Johnson, 1976) and CrystalMaker (CrystalMaker, 2005), Local programs.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C14—H3C14···N1i1.002.8823.723 (5)142
C14—H3C14···N1ii1.002.9583.348 (5)104
Symmetry codes: (i) x+1/2, y+1/2, z+1; (ii) x1/2, y1/2, z.
 

Acknowledgements

This research was supported by the UNSW Faculty Research Grants Program.

References

First citationAllen, F. H. (2002). Acta Cryst. B58, 380–388.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationAltomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.  CrossRef Web of Science IUCr Journals Google Scholar
First citationBishop, R. (2006). Crystal Engineering of Halogenated Heteroaromatic Clathrate Systems. In Frontiers in Crystal Engineering, ch. 5, pp. 91–116, edited by E. R. T. Tiekink & J. J. Vittal. Chichester: Wiley.  Google Scholar
First citationCheng, C.-C. & Yan, S.-J. (1982). Org. React. 28, 37–201.  CAS Google Scholar
First citationCrystalMaker (2005). CrystalMaker. CrystalMaker Software, Bicester, Oxfordshire, England. http://www.crystalmaker.co.ukGoogle Scholar
First citationDesiraju, G. R. & Gavezzotti, A. (1989). Acta Cryst. B45, 473–482.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationJohnson, C. K. (1976). ORTEPII, Oak Ridge National Laboratory, Tennessee, USA.  Google Scholar
First citationMarjo, C. E., Scudder, M. L., Craig, D. C. & Bishop, R. (1997). J. Chem. Soc. Perkin Trans. 2, pp. 2099–2104.  CrossRef Google Scholar
First citationPendrak, I., Wittrock, R. & Kingsbury, W. D. (1995). J. Org. Chem. 60, 2912–2915.  CrossRef CAS Web of Science Google Scholar
First citationRae, A. D. (2000). RAELS. Australian National University, Canberra.  Google Scholar
First citationSchaefer, J. P. & Honig, L. M. (1968). J. Org. Chem. 33, 2655–2659.  CrossRef CAS Web of Science Google Scholar
First citationSchagen, J. D., Straver, L., van Meurs, F. & Williams, G. (1989). CAD-4 Software. Version 5.0. Enraf–Nonius, Delft, The Netherlands.  Google Scholar

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