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

Natarajan Arumugam; Nurziana Ngah; Shafida Abd Hamid; Aisyah Saad Abdul Rahim

doi:10.1107/S1600536811048999

. 2011 Nov 30;67(Pt 12):o3453. doi: 10.1107/S1600536811048999

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

Natarajan Arumugam ^a, Nurziana Ngah ^b, Shafida Abd Hamid ^b, Aisyah Saad Abdul Rahim ^a,^*

PMCID: PMC3239083 PMID: 22199931

Abstract

In the title compound, C₂₀H₂₁BrN₂O₂, the bromophenyl ring is twisted by 40.13 (8)° from the benzimidazole mean plane and the Br atom deviates by 0.753 (1) Å from that plane. The sec-butyl group is disordered over two conformations in a 0.898 (5):0.102 (5) ratio. In the crystal, molecules related by translation along [ Inline graphic 10] are linked into chains via weak C—H⋯Br hydrogen bonds.

Related literature

For the synthesis and closely related structures, see: Arumugam et al. (2010 ▶, 2011 ▶); Navarrete-Vazquez et al. (2006 ▶). For therapeutic properties of benzimidazole derivatives, see: Vitale et al. (2008 ▶, 2009 ▶); Arienti et al. (2005 ▶). For standard bond lengths, see: Allen et al. (1987 ▶). For the low-temperature device used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₂₀H₂₁BrN₂O₂
M _r = 401.30
Monoclinic,
a = 10.5187 (2) Å
b = 12.7525 (2) Å
c = 13.7444 (2) Å
β = 98.101 (1)°
V = 1825.27 (5) Å³
Z = 4
Mo Kα radiation
μ = 2.27 mm⁻¹
T = 100 K
0.39 × 0.39 × 0.20 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.471, T _max = 0.666
24453 measured reflections
3221 independent reflections
3073 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.022
wR(F ²) = 0.056
S = 1.08
3221 reflections
248 parameters
12 restraints
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.24 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 datablock(s) global, I. DOI: 10.1107/S1600536811048999/cv5201sup1.cif

e-67-o3453-sup1.cif^{(23.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811048999/cv5201Isup2.hkl

e-67-o3453-Isup2.hkl^{(158KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811048999/cv5201Isup3.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
C16—H16A⋯Br1ⁱ	0.98	2.79	3.533 (2)	133

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Symmetry code: (i) Inline graphic .

Acknowledgments

NA, SAH and ASAR acknowledge the Malaysia Ministry of Science, Technology and Innovations (MOSTI) for funding the synthetic chemistry work under the R&D initiative grant No. 09-05-lfn-meb-004 and 304/PFARMASI/650544. NA thanks Universiti Sains Malaysia for the award of a postdoctoral fellowship.

supplementary crystallographic information

Comment

Accelerated condensation of substituted phenylenediamines with adducts of aldehydes under microwave conditions provides access into 2-arylbenzimidazoles (Navarrete-Vazquez et al., 2006; Arumugam et al., 2010; 2011). These 2-substituted benzimidazoles have recently gained attention due to their antiviral and antiproliferative activities (Vitale et al., 2008; 2009). Not only that, a series of novel 2-arylbenzimidazoles was found to exhibit highly selective inhibition on chk2 kinase, which helps to control DNA damage and could prove useful as an adjuvant to radiotherapy (Arienti et al., 2005). In continuation with our work in 2-arylbenzimidazoles (Arumugam et al., 2010; 2011), we present herein the X-ray crystal structure determination of the title compound.

The title compound, (Fig. 1), is similar to those previously reported, ethyl 1-sec-butyl-2-(4-chlorophenyl)-1H-benzimidazole-5- carboxylate (Arumugam et al., 2010) and ethyl 1-sec-butyl-2- (4-fluorophenyl)-1H-benzimidazole-5-carboxylate (Arumugam et al., 2011), except the bromine atom is attached at the para position of benzene ring.The bond lengths and angles are in normal ranges (Allen et al., 1987) and in agreement with those reported by Arumugam et al. (2010) and Arumugam et al. (2011). The sec-butyl group (C17/C18/C19/C20) is disordered over two conformations in a ratio 0.898 (5):0.102 (5). The bromophenyl ring (C1—C6/Br1) is twisted at 40.13 (8)° from the benzimidazole mean plane (C8/C9/C10/C11/C12/C13/N1/N2/C7) and Br atom deviates at 0.753 (1)Å from that plane.

In the crystal structure (Fig. 2), the molecules related by translation along [-110] are linked into chains via weak intermolecular C16—H16A···Br1 hydrogen bonds (Table 1).

Experimental

Preparation of the title compound was performed using the previous procedure described by Arumugam et al. (2010) and Arumugam et al. (2011). Recrystallization of the crude product from ethyl acetate furnished colourless crystals suitable for X-ray analysis.