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Acta Crystallogr Sect E Struct Rep Online. 2010 July 1; 66(Pt 7): o1742.
Published online 2010 June 23. doi:  10.1107/S1600536810021616
PMCID: PMC3006850

3,4-Dimeth­oxy­benzaldehyde [2,8-bis­(trifluoro­meth­yl)quinolin-4-yl]hydrazone

Abstract

In the title compound, C20H15F6N3O2, the quinoline ring system is almost coplanar with the benzene ring; the dihedral angle between the two planes is 2.31 (8)°. The crystal structure displays an inter­molecular C—H(...)F hydrogen bond. In addition, a weak π–π inter­action is observed between the unfused benzene ring and the benzene ring of quinoline, with a centroid–centroid distance of 3.586 (1) Å.

Related literature

For general background to quinolines, see: Mao et al. (2009 [triangle]); Bermudez et al.(2004 [triangle]); Jayaprakash et al. (2006 [triangle]); Andries et al. (2005 [triangle]). For related structures, see: Skörska et al. (2005 [triangle]).

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Object name is e-66-o1742-scheme1.jpg

Experimental

Crystal data

  • C20H15F6N3O2
  • M r = 443.35
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1742-efi1.jpg
  • a = 7.0359 (6) Å
  • b = 8.9617 (8) Å
  • c = 15.5315 (14) Å
  • α = 90.154 (1)°
  • β = 93.951 (1)°
  • γ = 96.449 (1)°
  • V = 970.75 (15) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.14 mm−1
  • T = 298 K
  • 0.22 × 0.15 × 0.12 mm

Data collection

  • Bruker SMART CCD area-detector diffractometer
  • Absorption correction: ψ scan (SADABS; Sheldrick, 2007 [triangle]) T min = 0.975, T max = 0.984
  • 9677 measured reflections
  • 3756 independent reflections
  • 2951 reflections with I > 2σ(I)
  • R int = 0.023

Refinement

  • R[F 2 > 2σ(F 2)] = 0.060
  • wR(F 2) = 0.175
  • S = 1.03
  • 3756 reflections
  • 281 parameters
  • H-atom parameters constrained
  • Δρmax = 0.51 e Å−3
  • Δρmin = −0.31 e Å−3

Data collection: SMART (Bruker, 2001 [triangle]); cell refinement: SAINT (Bruker, 2001 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 (Farrugia, 1997 [triangle]); software used to prepare material for publication: SHELXL97.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810021616/wn2391sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810021616/wn2391Isup2.hkl

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

Acknowledgments

We thank the DST, India, for funding under DST-FIST (Level II) for the X-ray diffraction facility at SSCU, IISc, Bangalore.

supplementary crystallographic information

Comment

2,8-Bis(trifluoromethyl)quinolin-4-yl]-(2-piperidyl)methanol (mefloquin) is a popular antimalarial drug. Further, studies have reported that it also possesses important structural features required for antimicrobial activity (Mao et al. 2009; Bermudez et al. 2004; Jayaprakash et al. 2006). Quinoline is the essential structural feature found in mefloquin and recently developed antimycobacterial drugs (Andries et al. 2005). Thus, quinoline derivatives are good lead molecules to further develop drug candidates against mycobacterium tuberculosis and as antibacterial agents. On the basis of these observations we have synthesized a quinoline derivative, in which a hydrazone group has been attached at the 4 position of the mefloquin structure, expecting that the newly designed molecule would exhibit some antibacterial activity. In this paper we report the crystal structure of 3,4-dimethoxybenzaldehyde [2,8-bis(trifluoromethyl)quinolin-4-yl]hydrazone.

The asymmetric unit of the title compound contains one molecule (Fig. 1). A very small dihedral angle [2.31 (8)°] between the quinoline system and the benzene ring indicates that these two systems are coplanar. In the crystal structure, intermolecular C12—H12···F1 hydrogen bonding (Table 1) involving the trifluoromethyl and methine groups results in the formation of a three-dimensional ladder-type network (Fig.2). In addition, a weak π-π interaction is observed between the benzene ring (C1-C6) and benzene ring (C13-C18) of quinoline, with a centroid-centroid distance of 3.586 (1) Å.

The crystal structures of the mefloquine base and its salt complexes have been reported (Skörska et al. 2005). However, these are only related to the quinoline portion of our structure.

Experimental

A mixture of [2,8-bis(trifluoromethyl)quinolin-4-yl]hydrazine (10 mmol) and 3,4 trimethoxy benzaldehyde (10 mmol) in glacial acetic acid (50 ml) was heated at reflux for 3 h. The reaction mixture was concentrated under reduced pressure, cooled, and the resulting solid hydrazone was filtered, washed with water and cold ethanol. The crude product was purified by column chromatography. Crystals suitable for X-ray analysis were obtained by dissolving the pure compound in hot methanol and slow evaporation of the solvent at room temperature. Yield: 72%, Mp. 487 K.

Refinement

All H atoms were placed at calculated positions; N—H = 0.86 Å, C—H = 0.93 Å for aromatic H, 0.96 Å for methyl H and refined using a riding model with Uiso(H) = 1.5Ueq(C) for methyl H and Uiso(H) = 1.2Ueq(C,N) for the imine H and all other carbon-bound H atoms.

Figures

Fig. 1.
The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen atoms are shown as spheres of arbitrary radius.
Fig. 2.
Packing of the molecules showing hydrogen bonds as dashed lines.

Crystal data

C20H15F6N3O2Z = 2
Mr = 443.35F(000) = 452
Triclinic, P1Dx = 1.517 Mg m3
Hall symbol: -P 1Melting point: 487 K
a = 7.0359 (6) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.9617 (8) ÅCell parameters from 3756 reflections
c = 15.5315 (14) Åθ = 2.3–25.9°
α = 90.154 (1)°µ = 0.14 mm1
β = 93.951 (1)°T = 298 K
γ = 96.449 (1)°Plate, colourless
V = 970.75 (15) Å30.22 × 0.15 × 0.12 mm

Data collection

Bruker SMART CCD area-detector diffractometer3756 independent reflections
Radiation source: fine-focus sealed tube2951 reflections with I > 2σ(I)
graphiteRint = 0.023
ω and [var phi] scansθmax = 25.9°, θmin = 2.3°
Absorption correction: ψ scan (SADABS; Sheldrick, 2007)h = −8→8
Tmin = 0.975, Tmax = 0.984k = −11→11
9677 measured reflectionsl = −19→19

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.060H-atom parameters constrained
wR(F2) = 0.175w = 1/[σ2(Fo2) + (0.0861P)2 + 0.4197P] where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
3756 reflectionsΔρmax = 0.51 e Å3
281 parametersΔρmin = −0.31 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.013 (3)

Special details

Experimental. 1H NMR (300 MHz, CD3 OD): δ, 3.886 (s, 3H, OCH3), 3.930 (s, 3H, OCH3) 7.047-7.019 (d, IH, 3,4-dimethoxyphenyl, J = 8.1Hz) 7.297-7.269 (t, 1H, trifluoromethylquinoline, J = 8.4Hz), 7.46 (s, IH, trifluoromethylquinoline), 7.667-7.640 (d, 1H, 3,4-dimethoxyphenyl, J=8.1Hz), 8.138-8.114 (d, 1H, trifluoromethylquinoline, J=7.2Hz), 8.26 (s, 1H, =CH), 8.263 (s, IH, 3,4-dimethoxyphenyl), 8.527-8.498 (d, IH, trifluoromethylquinoline, J=8.7Hz), 8.52 (s, 1H, N-H).
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 taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used 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 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
F10.2412 (5)0.4438 (2)1.01640 (13)0.1566 (13)
F20.1191 (7)0.3559 (3)1.1239 (2)0.211 (2)
F30.4056 (6)0.3784 (3)1.1201 (2)0.1887 (16)
F40.1562 (3)0.5209 (2)1.39246 (11)0.0901 (5)
F50.3417 (3)0.6419 (2)1.48883 (9)0.0978 (6)
F60.4605 (3)0.5329 (2)1.38655 (10)0.0913 (6)
O10.1621 (3)1.07781 (19)0.57898 (9)0.0638 (5)
O20.1874 (3)0.83177 (18)0.65840 (10)0.0688 (5)
N10.2843 (3)0.6043 (2)1.22381 (12)0.0578 (5)
N20.2663 (3)0.98738 (19)1.07163 (10)0.0507 (5)
H20.27331.07501.09510.061*
N30.2477 (3)0.97088 (19)0.98344 (10)0.0482 (4)
C10.3304 (3)1.0213 (3)1.34583 (14)0.0580 (6)
H10.34291.11381.37420.070*
C20.3326 (3)0.8892 (3)1.39354 (14)0.0582 (6)
H2A0.34490.89431.45350.070*
C30.3169 (3)0.7533 (3)1.35271 (13)0.0525 (5)
C40.2979 (3)0.7427 (2)1.26103 (13)0.0470 (5)
C50.2936 (3)0.8770 (2)1.21338 (12)0.0436 (5)
C60.3100 (3)1.0148 (2)1.25823 (13)0.0518 (5)
H60.30691.10341.22730.062*
C70.3190 (4)0.6124 (3)1.40417 (15)0.0689 (7)
C80.2689 (4)0.6011 (2)1.13901 (14)0.0591 (6)
C90.2625 (3)0.7229 (2)1.08485 (13)0.0538 (5)
H90.25090.70991.02520.065*
C100.2736 (3)0.8634 (2)1.12140 (12)0.0444 (5)
C110.2571 (6)0.4467 (3)1.09982 (19)0.0922 (11)
C120.2377 (3)1.0891 (2)0.94007 (13)0.0506 (5)
H120.24271.18040.96920.061*
C130.2186 (3)1.0878 (2)0.84631 (12)0.0450 (5)
C140.2105 (3)0.9538 (2)0.79899 (13)0.0478 (5)
H140.21670.86360.82790.057*
C150.1934 (3)0.9543 (2)0.71040 (13)0.0492 (5)
C160.1818 (3)1.0908 (2)0.66624 (12)0.0478 (5)
C170.1917 (3)1.2227 (2)0.71299 (13)0.0521 (5)
H170.18631.31340.68450.063*
C180.2096 (3)1.2204 (2)0.80233 (13)0.0514 (5)
H180.21561.31010.83320.062*
C190.2110 (5)0.6924 (3)0.69794 (18)0.0804 (8)
H19A0.20420.61540.65440.121*
H19B0.11130.66810.73650.121*
H19C0.33350.69890.72980.121*
C200.1384 (4)1.2097 (3)0.53018 (14)0.0654 (7)
H20A0.12621.18470.46980.098*
H20B0.24801.28250.54210.098*
H20C0.02511.25060.54580.098*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
F10.342 (4)0.0590 (11)0.0692 (12)0.0322 (16)0.0014 (16)−0.0190 (9)
F20.345 (5)0.0832 (16)0.196 (3)−0.085 (2)0.128 (3)−0.0574 (17)
F30.282 (4)0.1017 (18)0.190 (3)0.103 (2)−0.062 (3)−0.0563 (18)
F40.0978 (12)0.0869 (12)0.0843 (11)0.0028 (9)0.0072 (9)0.0326 (9)
F50.1344 (16)0.1228 (15)0.0411 (8)0.0407 (12)−0.0016 (8)0.0207 (8)
F60.1058 (13)0.1033 (13)0.0741 (10)0.0536 (10)0.0027 (9)0.0238 (9)
O10.0832 (11)0.0717 (11)0.0365 (8)0.0125 (8)−0.0023 (7)0.0003 (7)
O20.1029 (13)0.0560 (9)0.0466 (9)0.0126 (9)−0.0081 (8)−0.0122 (7)
N10.0775 (13)0.0495 (10)0.0471 (10)0.0120 (9)0.0014 (9)0.0041 (8)
N20.0750 (12)0.0433 (9)0.0338 (9)0.0082 (8)0.0023 (8)−0.0030 (7)
N30.0617 (11)0.0477 (9)0.0352 (9)0.0071 (8)0.0016 (7)−0.0013 (7)
C10.0635 (14)0.0646 (14)0.0457 (12)0.0051 (11)0.0053 (10)−0.0152 (10)
C20.0559 (13)0.0826 (16)0.0356 (10)0.0082 (11)−0.0001 (9)−0.0064 (10)
C30.0480 (11)0.0712 (14)0.0388 (11)0.0114 (10)−0.0001 (8)0.0043 (10)
C40.0475 (11)0.0536 (12)0.0403 (10)0.0092 (9)−0.0003 (8)0.0019 (8)
C50.0433 (10)0.0494 (11)0.0381 (10)0.0061 (8)0.0015 (8)−0.0027 (8)
C60.0580 (12)0.0523 (12)0.0450 (11)0.0053 (9)0.0053 (9)−0.0043 (9)
C70.0754 (17)0.0861 (18)0.0475 (13)0.0230 (15)−0.0017 (11)0.0141 (12)
C80.0836 (16)0.0457 (12)0.0479 (12)0.0085 (11)0.0013 (11)−0.0017 (9)
C90.0763 (15)0.0484 (12)0.0363 (10)0.0077 (10)−0.0004 (9)−0.0035 (8)
C100.0492 (11)0.0457 (11)0.0382 (10)0.0059 (8)0.0003 (8)0.0009 (8)
C110.172 (4)0.0439 (14)0.0622 (17)0.0193 (18)0.0067 (18)0.0032 (12)
C120.0666 (13)0.0453 (11)0.0404 (11)0.0091 (9)0.0034 (9)−0.0034 (9)
C130.0497 (11)0.0479 (11)0.0376 (10)0.0065 (8)0.0027 (8)−0.0005 (8)
C140.0542 (12)0.0468 (11)0.0419 (11)0.0063 (9)−0.0002 (9)0.0019 (8)
C150.0518 (11)0.0524 (12)0.0426 (11)0.0054 (9)−0.0032 (9)−0.0067 (9)
C160.0485 (11)0.0588 (12)0.0361 (10)0.0078 (9)0.0006 (8)−0.0006 (9)
C170.0624 (13)0.0510 (12)0.0438 (11)0.0101 (10)0.0037 (9)0.0079 (9)
C180.0664 (13)0.0465 (11)0.0422 (11)0.0096 (9)0.0049 (9)−0.0031 (9)
C190.125 (3)0.0507 (14)0.0645 (16)0.0107 (14)0.0008 (15)−0.0115 (11)
C200.0732 (15)0.0844 (17)0.0398 (11)0.0141 (13)0.0027 (10)0.0113 (11)

Geometric parameters (Å, °)

F1—C111.293 (3)C5—C61.406 (3)
F2—C111.272 (5)C5—C101.429 (3)
F3—C111.291 (5)C6—H60.9300
F4—C71.333 (3)C8—C91.383 (3)
F5—C71.336 (3)C8—C111.502 (3)
F6—C71.330 (3)C9—C101.372 (3)
O1—C161.356 (2)C9—H90.9300
O1—C201.425 (3)C12—C131.453 (3)
O2—C151.357 (3)C12—H120.9300
O2—C191.415 (3)C13—C181.378 (3)
N1—C81.314 (3)C13—C141.399 (3)
N1—C41.358 (3)C14—C151.373 (3)
N2—C101.359 (3)C14—H140.9300
N2—N31.373 (2)C15—C161.412 (3)
N2—H20.8600C16—C171.378 (3)
N3—C121.263 (3)C17—C181.385 (3)
C1—C61.359 (3)C17—H170.9300
C1—C21.399 (3)C18—H180.9300
C1—H10.9300C19—H19A0.9600
C2—C31.362 (3)C19—H19B0.9600
C2—H2A0.9300C19—H19C0.9600
C3—C41.423 (3)C20—H20A0.9600
C3—C71.497 (3)C20—H20B0.9600
C4—C51.417 (3)C20—H20C0.9600
C16—O1—C20118.09 (18)F2—C11—F3103.2 (3)
C15—O2—C19117.76 (18)F2—C11—F1106.1 (3)
C8—N1—C4115.71 (18)F3—C11—F1104.6 (3)
C10—N2—N3119.15 (16)F2—C11—C8114.2 (3)
C10—N2—H2120.4F3—C11—C8113.4 (3)
N3—N2—H2120.4F1—C11—C8114.3 (2)
C12—N3—N2116.75 (17)N3—C12—C13122.43 (19)
C6—C1—C2120.2 (2)N3—C12—H12118.8
C6—C1—H1119.9C13—C12—H12118.8
C2—C1—H1119.9C18—C13—C14118.76 (18)
C3—C2—C1120.41 (19)C18—C13—C12119.92 (18)
C3—C2—H2A119.8C14—C13—C12121.32 (18)
C1—C2—H2A119.8C15—C14—C13120.70 (19)
C2—C3—C4120.8 (2)C15—C14—H14119.7
C2—C3—C7120.1 (2)C13—C14—H14119.7
C4—C3—C7119.0 (2)O2—C15—C14125.5 (2)
N1—C4—C5123.44 (18)O2—C15—C16114.57 (18)
N1—C4—C3118.27 (19)C14—C15—C16119.92 (19)
C5—C4—C3118.29 (19)O1—C16—C17125.84 (19)
C6—C5—C4118.94 (18)O1—C16—C15114.91 (18)
C6—C5—C10123.79 (19)C17—C16—C15119.25 (18)
C4—C5—C10117.27 (18)C16—C17—C18120.15 (19)
C1—C6—C5121.3 (2)C16—C17—H17119.9
C1—C6—H6119.3C18—C17—H17119.9
C5—C6—H6119.3C13—C18—C17121.22 (19)
F6—C7—F4107.0 (2)C13—C18—H18119.4
F6—C7—F5106.04 (19)C17—C18—H18119.4
F4—C7—F5105.7 (2)O2—C19—H19A109.5
F6—C7—C3113.2 (2)O2—C19—H19B109.5
F4—C7—C3112.9 (2)H19A—C19—H19B109.5
F5—C7—C3111.5 (2)O2—C19—H19C109.5
N1—C8—C9126.8 (2)H19A—C19—H19C109.5
N1—C8—C11114.4 (2)H19B—C19—H19C109.5
C9—C8—C11118.8 (2)O1—C20—H20A109.5
C10—C9—C8118.24 (19)O1—C20—H20B109.5
C10—C9—H9120.9H20A—C20—H20B109.5
C8—C9—H9120.9O1—C20—H20C109.5
N2—C10—C9121.02 (18)H20A—C20—H20C109.5
N2—C10—C5120.47 (18)H20B—C20—H20C109.5
C9—C10—C5118.52 (18)
C10—N2—N3—C12178.62 (19)C6—C5—C10—N2−1.1 (3)
C6—C1—C2—C30.9 (3)C4—C5—C10—N2179.28 (18)
C1—C2—C3—C40.0 (3)C6—C5—C10—C9178.8 (2)
C1—C2—C3—C7−179.9 (2)C4—C5—C10—C9−0.8 (3)
C8—N1—C4—C50.8 (3)N1—C8—C11—F257.4 (5)
C8—N1—C4—C3−179.4 (2)C9—C8—C11—F2−122.5 (4)
C2—C3—C4—N1179.5 (2)N1—C8—C11—F3−60.4 (4)
C7—C3—C4—N1−0.7 (3)C9—C8—C11—F3119.7 (3)
C2—C3—C4—C5−0.7 (3)N1—C8—C11—F1179.8 (3)
C7—C3—C4—C5179.15 (19)C9—C8—C11—F1−0.1 (5)
N1—C4—C5—C6−179.6 (2)N2—N3—C12—C13179.74 (19)
C3—C4—C5—C60.6 (3)N3—C12—C13—C18−179.6 (2)
N1—C4—C5—C100.1 (3)N3—C12—C13—C14−0.1 (3)
C3—C4—C5—C10−179.77 (18)C18—C13—C14—C15−0.2 (3)
C2—C1—C6—C5−0.9 (3)C12—C13—C14—C15−179.7 (2)
C4—C5—C6—C10.2 (3)C19—O2—C15—C14−3.6 (4)
C10—C5—C6—C1−179.4 (2)C19—O2—C15—C16175.9 (2)
C2—C3—C7—F6−120.9 (2)C13—C14—C15—O2178.9 (2)
C4—C3—C7—F659.2 (3)C13—C14—C15—C16−0.6 (3)
C2—C3—C7—F4117.4 (3)C20—O1—C16—C17−3.8 (3)
C4—C3—C7—F4−62.4 (3)C20—O1—C16—C15176.45 (19)
C2—C3—C7—F5−1.5 (3)O2—C15—C16—O11.5 (3)
C4—C3—C7—F5178.7 (2)C14—C15—C16—O1−178.97 (19)
C4—N1—C8—C9−1.0 (4)O2—C15—C16—C17−178.3 (2)
C4—N1—C8—C11179.1 (3)C14—C15—C16—C171.2 (3)
N1—C8—C9—C100.2 (4)O1—C16—C17—C18179.2 (2)
C11—C8—C9—C10−179.9 (3)C15—C16—C17—C18−1.0 (3)
N3—N2—C10—C9−0.1 (3)C14—C13—C18—C170.4 (3)
N3—N2—C10—C5179.80 (17)C12—C13—C18—C17179.9 (2)
C8—C9—C10—N2−179.4 (2)C16—C17—C18—C130.2 (3)
C8—C9—C10—C50.8 (3)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C12—H12···F1i0.932.473.387 (3)168

Symmetry codes: (i) x, y+1, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WN2391).

References

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