Ethyl 2-methyl-4-phenyl­pyrido[1,2-a]benzimidazole-3-carboxyl­ate

Yan Qing Ge; Hai Yan Ge; Xiao Qun Cao

doi:10.1107/S1600536811039973

. 2011 Oct 5;67(Pt 11):o2846. doi: 10.1107/S1600536811039973

Ethyl 2-methyl-4-phenylpyrido[1,2-a]benzimidazole-3-carboxylate

Yan Qing Ge ^a, Hai Yan Ge ^a, Xiao Qun Cao ^a,^*

PMCID: PMC3247584 PMID: 22219889

Abstract

The title compound, C₂₁H₁₈N₂O₂, was synthesized using a novel tandem annulation reaction between (1H-benzimidazol-2-yl)(phenyl)methanone and (E)-ethyl 4-bromobut-2-enoate under mild conditions. The dihedral angles between the mean planes of the five-membered imidazole ring and the pyridine, benzene and phenyl rings are 0.45 (6), 1.69 (1) and 70.96 (8)°, respectively. In the crystal, molecules are linked through intermolecular C—H⋯N hydrogen bonds.

Related literature

For applications of nitrogen-containing heterocyclic compounds in the agrochemical and pharmaceutical fields, see: Ge et al. (2009 ▶). For the synthesis of the title compound, see: Ge et al. (2011 ▶). For the structure of 2,7,8-trimethyl-3-ethoxycarbonyl-4- phenylpyrido[1,2-a]benzimidazole, see: Ge et al.(2011 ▶). Some pyrido[1,2-a]benzimidazole derivatives are of interest for their biological activity, such as antineoplastic activity and central GABA-A receptor modulators for the treatment of anxiety, see: Badawey & Kappe (1999 ▶).

Experimental

Crystal data

C₂₁H₁₈N₂O₂
M _r = 330.37
Monoclinic,
a = 10.1176 (13) Å
b = 14.9136 (18) Å
c = 12.2648 (15) Å
β = 108.487 (2)°
V = 1755.1 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 298 K
0.26 × 0.22 × 0.19 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.979, T _max = 0.985
8867 measured reflections
3093 independent reflections
2515 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.096
S = 1.06
3093 reflections
227 parameters
H-atom parameters constrained
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Data collection: SMART (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811039973/fj2449sup1.cif

e-67-o2846-sup1.cif^{(20.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811039973/fj2449Isup2.hkl

e-67-o2846-Isup2.hkl^{(151.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811039973/fj2449Isup3.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
C17—H17⋯N2ⁱ	0.93	2.31	3.2092 (18)	164

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Symmetry code: (i) Inline graphic .

Acknowledgments

This study was supported by the Natural Science Foundation of Shandong Province (Y2007C135).

supplementary crystallographic information

Comment

Synthesis of nitrogen-containing heterocyclic compounds has been a subject of great interest due to the wide application in agrochemical and pharmaceutical fields (Ge et al.; 2011). Some pyrido[1,2-a]benzimidazole derivatives have been of interest for their biological activities, such as antineoplastic activity and central GABA-A receptor modulators for the treatment of anxiety (Badawey et al.; 1999). We report here the crystal structure of the title compound, (I) (Fig. 1)

Experimental

To a 50 ml round-bottomed flask were added (1H-benzo[d]imidazol-2-yl)(phenyl)methanone (1.00 mmol), (E)-ethyl 4-bromobut-2-enoate (2.00 mmol), potassium carbonate (0.28 g, 2.05 mmol) and dry DMF (10 ml). The mixture was stirred at room temperature for 6 h. The solvent was removed under reduced pressure and an product was isolated by column chromatography on silica gel (yield 74%). Crystals of (I) suitable for X-ray diffraction were obtained by allowing a refluxed solution of the product in ethyl acetate to cool slowly to room temperature (without temperature control) and allowing the solvent to evaporate for 3 d