Ethyl 4-(4-nitro­phen­yl)-2-(trifluoro­meth­yl)pyrimido[1,2-a]benzimidazole-3-carboxyl­ate

Feng-Ling Yang; Gong-Chun Li; Chang-Sheng Yao

doi:10.1107/S160053680803941X

. 2008 Nov 29;64(Pt 12):o2469. doi: 10.1107/S160053680803941X

Ethyl 4-(4-nitrophenyl)-2-(trifluoromethyl)pyrimido[1,2-a]benzimidazole-3-carboxylate

Feng-Ling Yang ^a,^*, Gong-Chun Li ^a, Chang-Sheng Yao ^b

PMCID: PMC2960121 PMID: 21581436

Abstract

In the title compound, C₂₀H₁₃F₃N₄O₄, the fused pyrimido[1,2-a]benzimidazole ring system is nearly planar, with a maximum deviation from the mean plane of 0.126 (1) Å. Molecules are linked by C—H⋯N and C—H⋯O hydrogen bonds and by π–π interactions with interplanar distances of 3.2661 (6) and 3.2775 (6) Å.

Related literature

For the bioactivity of benzo[4,5] imidazo[1,2-a]-pyrimidine derivatives, see: Abdel-Hafez (2007 ▶); Cheung et al. (2002 ▶); Nunes, Zhu, Amouzegh et al. (2005 ▶); Nunes, Zhu, Ermann et al. (2005 ▶ ▶). For the bioactivity of organofluorine compounds, see: Hermann et al. (2003 ▶); Ulrich (2004 ▶).

Experimental

Crystal data

C₂₀H₁₃F₃N₄O₄
M _r = 430.34
Monoclinic,
a = 8.4075 (5) Å
b = 26.6904 (14) Å
c = 9.0559 (5) Å
β = 111.027 (2)°
V = 1896.82 (18) Å³
Z = 4
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 113 (2) K
0.32 × 0.30 × 0.26 mm

Data collection

Rigaku Saturn diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2002 ▶) T _min = 0.961, T _max = 0.968
18499 measured reflections
4492 independent reflections
3911 reflections with I > 2σ(I)
R _int = 0.039

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.116
S = 1.11
4492 reflections
282 parameters
H-atom parameters constrained
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2002 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680803941X/fj2169sup1.cif

e-64-o2469-sup1.cif^{(21.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680803941X/fj2169Isup2.hkl

e-64-o2469-Isup2.hkl^{(220.1KB, 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
C12—H12⋯N3ⁱ	0.95	2.41	3.2987 (18)	156
C16—H16⋯O3ⁱⁱ	0.95	2.55	3.2096 (18)	127

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

Acknowledgments

The authors thank the Natural Science Foundation of Henan Province, China (grant No. 082300420110) and the Natural Science Foundation of Henan Province Eduation Department, China (grant No. 2007150036) for financial support.

supplementary crystallographic information

Comment

Among the derivatives of the dihydropyrimidine, the derivatives of pyrimido[1,2-a]benzimidazole have been reported to have a variety of biological activities, such as antineoplastic activity (Abdel-Hafez, 2007), protein kinase inhibitor (Nunes, Zhu, Amouzegh et al., 2005), T cell activation (Nunes, Zhu, Ermann et al., 2005), TIE-2 and/or VEGFR2 inhibitory activities (Cheung et al, 2002). Besides, compounds that contain fluorine have special bioactivity, for example, flumioxazin is a widely used herbicide (Hermann et al., 2003; Ulrich,2004). This led us to pay much attention to the synthesis and bioactivity of these important fused perfluoroalkylated heterocyclic compounds. To further study the relationship between the structure and bioactivity, we synthesised series of derivatives of benzo[4,5] pyrimido[1,2-a]benzimidazole. Here we report the crystal structure of the title compound, (I).

In the title molecule (Fig.1), the fused ring are near planar, for the dihedral angle between the phenyl ring/imidazole ring/pyrimidine ring are 3.68 (9) and 3.65 (8)°, respectively. The conformation of the attachment of the phenyl ring to the fused ring is described by the torsion angle of N2-C2-C11-C16 of 123.17 (14)°.

The crystal packing is stabilized by C—H···N and C—H···O intermolecular hydrogen bond (Table 1, Fig. 2). In addition, there are the intermolecular π–π stacking interacions between the two neighbouring parallel imidazole rings(symmetry code: 1-x,1-y,1-z; centroid-to-centroid distance: 3.3386 (9)Å, plane-plane distance: 3.2661 (6)Å, displacement distance: 0.692Å) and phenyl rings (C5-C10, symmetry code: -x,1-y,1-z; centroid-to-centroid distance: 3.9822 (9)Å, plane-plane distance: 3.2775 (6)Å, displacement distance: 2.262Å) in the title compound.

Experimental

The title compound was synthesized by the reaction of 4-nitrobenzaldehyde (1 mmol), ethyl 4,4,4-trifluoro-3-oxobutanoate (1 mmol) and 1H-benzo[d]imidazol-2-amine (1 mmol) in 3-butyl-1-methyl-1H- imidazol-3-ium chloride (1.5 mL) at 363 K for a certain time (monitered by TLC). After cooling, the reaction mixture was washed with water and recrystallized from ethanol, to obtain single crystals suitable for X-ray diffraction.