Crystal structure of cis-1-(2-methyl-1,2,3,4-tetra­hydro­quinolin-4-yl)azepan-2-one

P S Pradeep; S Naveen; M N Kumara; K M Mahadevan; N K Lokanath

doi:10.1107/S1600536814017826

. 2014 Aug 9;70(Pt 9):o981–o982. doi: 10.1107/S1600536814017826

Crystal structure of cis-1-(2-methyl-1,2,3,4-tetrahydroquinolin-4-yl)azepan-2-one

P S Pradeep ^a, S Naveen ^b, M N Kumara ^c, K M Mahadevan ^a, N K Lokanath ^d,^*

PMCID: PMC4186183 PMID: 25309292

Abstract

In the title compound, C₁₆H₂₂N₂O, the azepan-2-one ring adopts a chair conformation, while the 1,2,3,4-tetrahydropyridine ring adopts a half-chair conformation. In the crystal, molecules are linked by N—H⋯O hydrogen bonds, forming supramolecular chains propagated along [10-1], with weak C—H⋯O interactions occurring between the chains.

Keywords: crystal structure, tetrahydroquinolines, azepan-2-one, hydrogen bonding

Related literature

For applications of tetrahydroquinolines, see: Konishi et al. (1990 ▶).

Experimental

Crystal data

C₁₆H₂₂N₂O
M _r = 258.36
Monoclinic,
a = 9.1640 (17) Å
b = 13.1687 (18) Å
c = 11.988 (2) Å
β = 96.825 (11)°
V = 1436.4 (4) Å³
Z = 4
Cu Kα radiation
μ = 0.59 mm⁻¹
T = 296 K
0.23 × 0.22 × 0.21 mm

Data collection

Bruker X8 Proteum diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2013 ▶) T _min = 0.874, T _max = 0.884
7903 measured reflections
2343 independent reflections
2106 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.139
S = 1.06
2343 reflections
173 parameters
H-atom parameters constrained
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.36 e Å⁻³

Data collection: APEX2 (Bruker, 2013 ▶); cell refinement: SAINT (Bruker, 2013 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: Mercury.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536814017826/xu5808sup1.cif

e-70-0o981-sup1.cif^{(25.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814017826/xu5808Isup2.hkl

e-70-0o981-Isup2.hkl^{(115.2KB, hkl)}

Click here for additional data file.^{(5.9KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814017826/xu5808Isup3.cml

Click here for additional data file.^{(3.1MB, tif)}

. DOI: 10.1107/S1600536814017826/xu5808fig1.tif

A view of the title molecule, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

Click here for additional data file.^{(2.3MB, tif)}

a . DOI: 10.1107/S1600536814017826/xu5808fig2.tif

A viewed along the a axis of the crystal packing of the title compound.

CCDC reference: 1017682

Additional supporting information: 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⋯O19ⁱ	0.86	2.40	2.988 (2)	126
C14—H14A⋯O19ⁱⁱ	0.97	2.57	3.320 (2)	134

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

Acknowledgments

The authors are thankful to IOE, Vijnana Bhavana, University of Mysore, Mysore, for providing the single-crystal X-ray diffractometer facility.

supplementary crystallographic information

S1. Comment

Tetrahydroquinolines are an important family of heterocyclic compounds having wide range of biological activities which includes antimalarial, antitumoral, antioxidant, etc. In particular 2-Methyl-1,2,3,4-tetrahydroquinoline is present in human brain and a natural antitumor antibiotic, has a complex structure built on the tetrahydroquinoline system (Konishi et al., 1990). Hence, in continuation of our effort to identify new quinoline based therapeutic agents, the title compound has been synthesized and herein we report its crystal structure.

The ORTEP of the molecule is shown in figure 1. The title compound is chiral. In the arbitrarily chosen asymmetric molecule, C2 has S configuration whereas C4 has R configuration. The azepan ring lies in the equatorial plane of the fused rings as indicated by the dihedral angle value of 66.28 (8)°. A study of torsion angles, asymmetric parameters and least squares plane calculations reveals that the quinoline ring in the structure adopts a half chair conformation with the atom C3 deviating by 0.3278 (18) Å from the least-squares plane defined by the atoms N1/C2/C3/C4/C5/C10. This is confirmed by the puckering amplitude Q = 0.4857 (18) Å. The structure exhibits weak intermolecular hydrogen bonds of the type C—H···O and N—H···O. The packing of the molecules when viewed along the a axis indicate that they are stacked in pairs.

S2. Experimental

A catalytic amount of SbF₃ (10 mol %) was added to the mixture of aniline(1 equivalent) and N-vinyl caprolactam(2–3 equivalent) in acetonitrile (5–10 ml). The reaction mixture was stirred at ambient temperature (~25 °C) for 20–70 min. The reaction was monitored by TLC by using ethyl acetate/hexane as eluent. After the completion of the reaction, the solvent was removed under vacuo. The crude product was then quenched with water and the catalyst was decomposed by addition of appropriate amount of sodium bicarbonate solution, extracted with ethyl acetate (10 ml × 5 times), dried and was purified by column chromatography using ethyl acetate/hexane as eluent (pet ether/ethyl acetate 80:20 v/v). The white solid crystals were obtained by slow evaporation method by using petroleum ether: ethyl acetate, 8:2 v/v as solvents. M.P. = 155–160 °C. Yield: 93%.