Crystal structure of 2-(4-meth­oxy­phen­yl)-6-nitro­imidazo[1,2-a]pyridine-3-carbaldehyde

Mohamed Koudad; Abdelmalik Elaatiaoui; Noureddine Benchat; Mohamed Saadi; Lahcen El Ammari

doi:10.1107/S2056989015021957

. 2015 Nov 21;71(Pt 12):o979–o980. doi: 10.1107/S2056989015021957

Crystal structure of 2-(4-methoxyphenyl)-6-nitroimidazo[1,2-a]pyridine-3-carbaldehyde

Mohamed Koudad ^a,^b, Abdelmalik Elaatiaoui ^a,^b,^*, Noureddine Benchat ^a, Mohamed Saadi ^c, Lahcen El Ammari ^c

PMCID: PMC4719933 PMID: 26870561

Abstract

In the title compound, C₁₅H₁₁N₃O₄, the imidazo[1,2-a] pyridine ring system is almost planar [r.m.s. deviation = 0.028 (2) Å]. Its mean plane makes dihedral angles of 33.92 (7) and 34.56 (6)° with the methoxyphenyl ring and the nitro group, respectively. The cohesion of the crystal structure is ensured by C—H⋯N and C—H⋯O hydrogen bonds, forming layers almost parallel to the ac plane.

Keywords: crystal structure; imidazo[1,2-a]pyridine; carbaldehyde; hydrogen bonding

Related literature

For biological activities of derivatives of the title compound, see: Rupert et al. (2003 ▸); Hranjec et al. (2007 ▸); Hamdouchi et al. (1999 ▸); Rival et al. (1992 ▸); Scribner et al. (2008 ▸); Bode et al. (2011 ▸). For the synthesis of similar compounds, see: Sumalatha et al. (2009 ▸); Elaatiaoui et al. (2014 ▸, 2015 ▸).

Experimental

Crystal data

C₁₅H₁₁N₃O₄
M _r = 297.27
Monoclinic,
a = 10.8516 (6) Å
b = 12.0710 (6) Å
c = 10.2631 (5) Å
β = 93.200 (2)°
V = 1342.26 (12) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 296 K
0.42 × 0.31 × 0.26 mm

Data collection

Bruker X8 APEX diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▸) T _min = 0.673, T _max = 0.746
25892 measured reflections
3472 independent reflections
2139 reflections with I > 2σ(I)
R _int = 0.060

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.120
S = 1.02
3472 reflections
200 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▸); cell refinement: SAINT (Bruker, 2009 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸); software used to prepare material for publication: PLATON (Spek, 2009 ▸) and publCIF (Westrip, 2010 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989015021957/su5244sup1.cif

e-71-0o979-sup1.cif^{(940KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015021957/su5244Isup2.hkl

e-71-0o979-Isup2.hkl^{(277.2KB, hkl)}

Click here for additional data file.^{(5.5KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015021957/su5244Isup3.cml

Click here for additional data file.^{(1.1MB, tif)}

. DOI: 10.1107/S2056989015021957/su5244fig1.tif

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

Click here for additional data file.^{(1.4MB, tif)}

. DOI: 10.1107/S2056989015021957/su5244fig2.tif

A partial view of the crystal packing of the title compound, showing molecules linked by hydrogen bonds (dashed lines; Table 1), forming layers parallel to (101).

CCDC reference: 1437519

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
C4—H4⋯N3ⁱ	0.93	2.53	3.412 (2)	158
C15—H15A⋯O3ⁱⁱ	0.96	2.52	3.423 (2)	158
C14—H14⋯O1ⁱⁱⁱ	0.93	2.50	3.425 (2)	177

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

Acknowledgments

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

supplementary crystallographic information

S1. Structural commentary

Imidazo[1,2-a]pyridines are a very interesting class of heterocyclic compounds because of their wide use in medicinal chemistry for the production of various pharmacologically active agents. In addition, various derivatives of imidazo[1,2-a]pyridine show a wide range of biological activities such as anti-inflammatory (Rupert et al., 2003), antitumor (Hranjec et al., 2007), antiviral (Hamdouchi et al., 1999), antibacterial (Rival et al., 1992), antiparasitic (Scribner et al., 2008) and anti-HIV (Bode et al., 2011). The access to the imidazo[1,2-a]pyridine scaffold is generally made by condensation of 2-aminopyridine with a specifically chosen α-halo ketone (Sumalatha et al., 2009). The present paper is a continuation of our research devoted to the development of imidazo[1,2-a]pyridines derivatives with potential pharmacological activities (Elaatiaoui et al., 2014;2015).

In the title compound, Fig. 1, the fused five- and six-membered rings of the imidazo[1,2-a]pyridine moiety are virtually coplanar, with a maximum deviation of 0.028 (2) Å for atom C3. Its mean plane makes dihedral angles of 33.92 (7) and 34.56 (6)° with the methoxyphenyl ring and the nitro group, respectively.

In the crystal, molecules are linked by C4–H4···N3, C15–H15A···O3 and C14–H14···O1 hydrogen bonds (Table 1), building layers parallel to (101), as shown in Fig. 2.

S2. Synthesis and crystallization

Phosphorus oxychloride (3.06 g, 0.02 mol) was added to a solution of 2-(4-methoxyphenyl)-5-nitroimidazo[1,2-a]pyridine (2.69 g, 0.01 mol) in DMF (25 ml) at room temperature under stirring. The mixture was heated to 353 K for 5 h. The resulting solution was evaporated to dryness in vacuo, and the residue was treated with cold water, filtered, and crystallized from methanol to give pure product (yield 74%, Rf = 0.45 (silica, CH₂Cl₂/MeOH, 9/1).

Spectral data: ¹H NMR (300 MHz, DMSO, δ(p.p.m.)): 10.40 (s, 1H, C₅H); 10.09 (s, 1H, CH=O); 8.36 (dd, 1H, C₇H, J=2.4 Hz); 7.96 (m, 3H,C₈H, CphH, CphH, J= 28.2 Hz); 7.10 (d, 2H, CphH, CphH, J=9 Hz); 3.83 (s, 3H, OCH₃). ¹³C NMR (75 MHz, DMSO) δ(p.p.m.): 180.84; 161.64; 158.81; 147.76; 138.75; 131.75; 128.32; 125.06; 124.05; 121.11; 117.04; 115.02; 55.87. m/z (M+1): 298.09.

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. H atoms were located in a difference Fourier map and treated as riding: C–H = 0.93-0.96 Å with U_iso(H) = 1.5 U_eq for methyl H atoms and 1.2 U_eq for other H atoms. The reflection (100) affected by the beam-stop was removed during refinement.