Ethyl 4-oxo-8-trifluoro­methyl-1,4-dihydro­quinoline-3-carboxyl­ate

B Garudachari; Arun M Islor; M N Satyanarayan; Thomas Gerber; Eric Hosten; Richard Betz

doi:10.1107/S1600536812045321

. 2012 Nov 10;68(Pt 12):o3304–o3305. doi: 10.1107/S1600536812045321

Ethyl 4-oxo-8-trifluoromethyl-1,4-dihydroquinoline-3-carboxylate

B Garudachari ^a, Arun M Islor ^a, M N Satyanarayan ^b, Thomas Gerber ^c, Eric Hosten ^c, Richard Betz ^c,^*

PMCID: PMC3588845 PMID: 23468810

Abstract

The asymmetric unit of the title compound, C₁₃H₁₀F₃NO₃, contains two independent molecules with similar conformations. In the crystal, N—H⋯O hydrogen bonds link alternating independent molecules into chains in [-110]. In the chain, the quinoline planes of the independent molecules are almost perpendicular to each other, forming a dihedral angle of 89.8 (1)°. π–π interactions between the aromatic rings of quinoline bicycles related by inversion centres [for two independent centrosymmetric dimers, the shortest centroid–centroid distances are 3.495 (1) and 3.603 (1) Å] link the hydrogen-bonded chains into layers parallel to (110). Weak C—H⋯F and C—H⋯O interactions further consolidate the crystal packing.

Related literature

For background information about the pharmacological properties of quinoline derivatives, see: Holla et al. (2006 ▶); Bekhit et al. (2004 ▶); Kaur et al. (2010 ▶); Isloor et al. (2009 ▶); Vijesh et al. (2011 ▶). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990 ▶); Bernstein et al. (1995 ▶). For the synthesis of the title compound, see: Thomas et al. (2011 ▶).

Experimental

Crystal data

C₁₃H₁₀F₃NO₃
M _r = 285.22
Triclinic,
a = 9.8248 (3) Å
b = 11.0222 (3) Å
c = 12.3450 (4) Å
α = 72.934 (1)°
β = 74.167 (1)°
γ = 74.059 (1)°
V = 1201.67 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.14 mm⁻¹
T = 200 K
0.53 × 0.38 × 0.32 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.928, T _max = 0.956
21419 measured reflections
5963 independent reflections
5051 reflections with I > 2σ(I)
R _int = 0.016

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.116
S = 1.04
5963 reflections
371 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.39 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2010 ▶); cell refinement: SAINT (Bruker, 2010 ▶); 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, 2012 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(32.7KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812045321/cv5354sup1.cif

e-68-o3304-sup1.cif^{(32.7KB, cif)}

Click here for additional data file.^{(2.3KB, cdx)}

Supplementary material file. DOI: 10.1107/S1600536812045321/cv5354Isup2.cdx

Click here for additional data file.^{(291.9KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812045321/cv5354Isup3.hkl

e-68-o3304-Isup3.hkl^{(291.9KB, hkl)}

Click here for additional data file.^{(5KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536812045321/cv5354Isup4.cml

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—H1⋯O21ⁱ	0.892 (19)	1.875 (19)	2.6588 (13)	145.5 (16)
N2—H2⋯O11ⁱⁱ	0.851 (18)	2.011 (17)	2.7178 (13)	139.9 (16)
N2—H2⋯O12ⁱⁱ	0.851 (18)	2.487 (17)	3.0380 (15)	123.2 (14)
C212—H21B⋯F22ⁱⁱⁱ	0.99	2.46	3.0909 (18)	121
C204—H204⋯O13^iv	0.95	2.60	3.4691 (18)	153

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

Acknowledgments

AMI thanks the Board for Research in Nuclear Sciences, Department of Atomic Energy, Government of India, for the Young Scientist award.

supplementary crystallographic information

Comment

Quinoline derivatives constitute an important class of compounds that are widely found in plants. A number of synthetic analogues have been developed over the years. Some of them exhibit remarkable effects such as antimicrobial, anti-inflammatory and antimalarial (Holla et al., 2006; Bekhit et al., 2004; Kaur et al., 2010). This follows a broader trend that shows nitrogen-containing heterocycles to be among pharmaceutically active and interesting compounds (Isloor et al., 2009; Vijesh et al., 2011) which justifies our continuing efforts in designing novel heterocyclic molecules of biological importance and study their respective molecular and crystal structure.

The title compound is a derivative of 1,4-dihydroquinoline and does not adopt its aromatic tautomeric form as a quinoline derivative. There are two independent molecules in the asymmetric unit (Fig. 1).

In the crystal, classical N—H···O hydrogen bonds (Table 1) link the alternating independent molecules into chains in [-110] (Fig. 2). In the chain, the quinoline planes of independent molecules are almost perpendicular to each other forming a dihedral angle of 89.8 (1)°. The π–π interactions between the aromatic rings of the quinoline bicycles related by inversion centres [for two independent centrosymmetric dimers the shortest intercentroid distances are 3.495 (1) and 3.603 (1) Å, respectively] link hydrogen-bonded chains into layers parallel to the (110) plane. Weak intermolecular C–H···F contacts are observed next to intermolecular C–H···O contacts (Table 1). In every case, the range of these contacts falls by more than 0.1 Å below the sum of van-der-Waals radii of the atoms participating in them. While the C–H···O contacts stem from one of the hydrogen atoms on the phenyl moiety bearing the trifluoromethyl substituent and apply the ethereal oxygen atom as acceptor, the classical hydrogen bonds invariably have double bonded oxygen atoms as acceptors. These hydrogen bonds intermittently connect the two different molecules present in the asymmetric unit into chains along [-110] and show bifurcation between the two double bonded oxygen atoms in one case. In total, these contacts connect the molecules to planes parallel to ab. In terms of graph-set analysis (Etter et al., 1990; Bernstein et al., 1995), the descriptor for the classical hydrogen bonds is DDD on the unary level (taking into account the bifurcation). The descriptor for the C–H···O contacts is D while a C¹₁(11) descriptor is found for the C–H···F contacts on the same level.

Experimental

Diethyl({[3-(trifluoromethyl)phenyl]amino}methylene)malonate (10.0 g, 0.030 mol) and Dowtherm (100 ml) were heated to 250 °C for 5 h. The reaction mixture was then cooled to 25 °C and stirred in n-hexane (150 ml) for 10 min. The solid product obtained was filtered, dried and recrystallized from ethanol, yield: 8.0 g (93.0%) (Thomas et al., 2011).