Ethyl 1-sec-butyl-2-(4-methoxy­phen­yl)-1H-benzimidazole-5-carboxyl­ate

Natarajan Arumugam; Aisyah Saad Abdul Rahim; Hasnah Osman; Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536810007634

. 2010 Mar 17;66(Pt 4):o845. doi: 10.1107/S1600536810007634

Ethyl 1-sec-butyl-2-(4-methoxyphenyl)-1H-benzimidazole-5-carboxylate

Natarajan Arumugam ^a, Aisyah Saad Abdul Rahim ^a,^‡, Hasnah Osman ^b, Madhukar Hemamalini ^c, Hoong-Kun Fun ^c,^*,^§

PMCID: PMC2983837 PMID: 21580670

Abstract

In the title molecule, C₂₁H₂₄N₂O₃, the dihedral angle between the benzene and imidazole rings is 66.33 (13)°. The imidazole ring is essentially planar, with a maximum deviation of 0.004 (2) Å. In the crystal structure, molecules are connected by weak C—H⋯O hydrogen bonds, forming chains along the b axis

Related literature

For the benzimidazole nucleus as a key building block for compounds showing biologically activity, see: Tanious et al. (2004 ▶). For the therapeutic properties of benzimidazole derivatives, see: Kohara et al. (1996 ▶); Mader et al. (2008 ▶). For 2-substituted-phenylbenzimidazoles with biological activity, see: Coburn et al. (1987 ▶); Roth et al. (1997 ▶).

Experimental

Crystal data

C₂₁H₂₄N₂O₃
M _r = 352.42
Monoclinic,
a = 10.5815 (3) Å
b = 12.1079 (3) Å
c = 15.1050 (3) Å
β = 93.678 (2)°
V = 1931.26 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 296 K
0.40 × 0.31 × 0.07 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.968, T _max = 0.994
19216 measured reflections
4437 independent reflections
2266 reflections with I > 2s(I)
R _int = 0.065

Refinement

R[F ² > 2σ(F ²)] = 0.066
wR(F ²) = 0.150
S = 1.04
4437 reflections
235 parameters
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810007634/tk2635sup1.cif

e-66-0o845-sup1.cif^{(21.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810007634/tk2635Isup2.hkl

e-66-0o845-Isup2.hkl^{(217.4KB, 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
C21—H21C⋯O1ⁱ	0.96	2.47	3.389 (4)	161

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Symmetry code: (i) Inline graphic .

Acknowledgments

NA, ASAR and HO are grateful to Universiti Sains Malaysia (USM) for funding the synthetic chemistry research under the USM Research University grant (1001/PFARMASI/815026). NA thanks USM for the award of postdoctoral fellowship. HKF and MH thank the Malaysian Government and USM for the Research University Golden Goose grant No. 1001/PFIZIK/811012. MH also thanks USM for a post-doctoral research fellowship.

supplementary crystallographic information

Comment

The benzimidazole nucleus is the key building block for a variety of compounds that play crucial roles in the function of a number of biologically important molecules (Tanious et al., 2004). Benzimidazole derivatives have shown different therapeutic properties such as antihypertensive (Kohara et al., 1996) and anti-inflammatory (Mader et al., 2008) activities. 2-(substitutedphenyl)benzimidazoles with various types of biological activities, such as antibacterial (Coburn et al., 1987) and antiviral (Roth et al., 1997), have been reported. Due to their importance, the crystal structure determination of the title compound was carried out and the results are presented here.

In the title molecule (Fig. 1), the imidazole ring is essentially planar with a maximum deviation of 0.004 (2) Å for atom C13. The dihedral angle between the imidazole ring (N1/N2/C13/C7–C8) and the benzene ring (C1–C6) is 66.33 (13)° . In the crystal structure (Fig. 2), the molecules are connected by weak C21—H21C···O1 (Table 1) hydrogen bonds, forming one-dimensional chains along the b axis.

Experimental

Ethyl-3-amino-4-(sec-butylamino)benzoate (200 mg, 0.84 mmol) and the sodium metabisulfite adduct of 4-methoxy benzaldehyde (406 mg, 1.68 mmol) were dissolved in DMF. The reaction mixture was irradiated under microwave conditions at 403 K for 2 minutes. After completion of the reaction, the reaction mixture was diluted in EtOAc (20 ml) and washed with H₂O (20 ml). The organic layer was collected, dried over Na₂SO₄ and then evaporated in vacuo to yield the crude product. The product was recrystallized from hot EtOAc to afford the title compound as colorless crystals.