2-Meth­oxy­quinoline-3-carbaldehyde

K Chandraprakash; P Ramesh; K Ravichandran; P S Mohan; M N Ponnuswamy

doi:10.1107/S1600536810034744

. 2010 Sep 4;66(Pt 10):o2510. doi: 10.1107/S1600536810034744

2-Methoxyquinoline-3-carbaldehyde

K Chandraprakash ^a, P Ramesh ^b, K Ravichandran ^b, P S Mohan ^a, M N Ponnuswamy ^b,^*

PMCID: PMC2983248 PMID: 21587505

Abstract

In the title compound, C₁₁H₉NO₂, the quinoline ring system is essentially planar (r.m.s. deviation = 0.005 Å) and the methoxy and aldehyde groups are almost coplanar with it [N—C—O—C = 6.24 (19) and O—C—C—C = 0.3 (2)°]. In the crystal, molecules are linked by pairs of C—H⋯O hydrogen bonds, forming centrosymmetric R ₂ ²(10) dimers. The dimers are linked via π–π interactions involving the pyridine and benzene rings [centroid–centroid distance = 3.639 (1) Å].

Related literature

For general background to quinoline derivatives, see: Mali et al. (2010 ▶); Kuethe et al. (2003 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₁H₉NO₂
M _r = 187.19
Monoclinic,
a = 8.8206 (6) Å
b = 4.8446 (3) Å
c = 21.6828 (14) Å
β = 90.612 (4)°
V = 926.50 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.20 × 0.20 × 0.18 mm

Data collection

Bruker SMART APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.981, T _max = 0.983
8812 measured reflections
2305 independent reflections
1658 reflections with I > 2σ(I)
R _int = 0.030

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.130
S = 1.05
2305 reflections
128 parameters
H-atom parameters constrained
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); 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, 1997 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810034744/ci5162sup1.cif

e-66-o2510-sup1.cif^{(15.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810034744/ci5162Isup2.hkl

e-66-o2510-Isup2.hkl^{(111KB, hkl)}

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
C4—H4⋯O2ⁱ	0.93	2.56	3.4157 (16)	152

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank TBI consultancy, University of Madras, India, for the data collection

supplementary crystallographic information

Comment

Quinolines have gained importance in medicinal and natural product chemistry due to their interesting biological and pharmacological activities. They possess anti-malarial, anti-tuberculosis, anti-inflammatory and anti-cancer properties (Mali et al., 2010). Methoxy substituted quinolines are used as synthetic intermediates in the construction of novel class of KDR kinase inhibitors (Kuethe et al., 2003). Against this background and to ascertain the structure of title compound, the crystallographic studies have been carried out.

In the title molecule (Fig.1), the quinoline ring system (N1/C2–C10) is essentially planar with a maximum deviation of 0.007 (1) Å for atom C3. The methoxy and carbaldehyde groups are almost coplanar with the quinoline ring system, which is evidenced from torsion angles C3—C2—O1—C11 and C2—C3—C12—O2 of 173.6 (1)° and 178.5 (2)°, respectively.

The packing of the molecules in the crystal is stabilized by C—H···O, and π–π types of intermolecular interactions. The molecules at (x, y, z) and (1-x, 1-y, 1-z) are linked by a pair of intermolecular C4—H4···O2 hydrogen bonds to form a centrosymmetric dimer containing R₂²(10) ring motif (Fig. 2) (Bernstein et al., 1995). The π–π interaction between the pyridine ring (N1/C2-C10) of the quinoline ring system at (x, y, z) and the benzene ring (C5—C10) at (x, y-1, z) further stabilize the structure, with a centroid-centroid distance of 3.639 (1) Å.

Experimental

To a solution of 1 g (17.8 mmol) of KOH in 50 ml of MeOH was added 2.5 g (13.1 mmol) of 2-chloro-3-quinolinecarboxaldehyde. The mixture was heated at 373 K for 2.5 h and then cooled to room temperature, and poured into 200 g of crushed ice. The precipitate thus obtained was recuperated by filtration. The obtained product was a colourless solid. The product was purified by recrystallization from petroleum ether-ethyl acetate mixture.