Ethyl 1-tert-butyl-2-(4-hydr­oxy-3-methoxy­phen­yl)-1H-benzimidazole-5-carboxyl­ate

Natarajan Arumugam; Aisyah Saad Abdul Rahim; Hasnah Osman; Mohd Mustaqim Rosli; Hoong-Kun Fun

doi:10.1107/S1600536810011918

. 2010 Apr 10;66(Pt 5):o1051–o1052. doi: 10.1107/S1600536810011918

Ethyl 1-tert-butyl-2-(4-hydroxy-3-methoxyphenyl)-1H-benzimidazole-5-carboxylate

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

PMCID: PMC2979157 PMID: 21579111

Abstract

In the title compound, C₂₁H₂₄N₂O₄, the benzimidazole ring system is almost planar, with a maximum deviation of 0.047 (1) Å and makes a dihedral angle of 88.44 (5)° with the attached benzene ring. In the crystal, molecules form infinite chains along the b axis by way of intermolecular O—H⋯N and C—H⋯O interactions. Weak C—H⋯π also contribute to the stabilization of the crystal structure.

Related literature

For the biological properties of benzimidazole-based heterocyclic compounds, see: Townsend et al. (1970 ▶); Blythin et al. (1986 ▶); Lemura et al. (1986 ▶); Zhang et al. (2008 ▶); Bonfanti et al. (2008 ▶); Ozden et al. (2008 ▶). For related structures, see Arumugam, Abd Hamid et al. (2010 ▶); Arumugam, Abdul Rahim, Abd Hamid et al. (2010 ▶); Arumugam, Abdul Rahim, Osman et al. (2010 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₂₁H₂₄N₂O₄
M _r = 368.42
Monoclinic,
a = 9.2610 (6) Å
b = 13.6096 (9) Å
c = 16.3200 (9) Å
β = 113.560 (3)°
V = 1885.5 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.38 × 0.23 × 0.15 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.967, T _max = 0.986
21041 measured reflections
5484 independent reflections
4104 reflections with I > 2σ(I)
R _int = 0.039

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.134
S = 1.07
5484 reflections
253 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); 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/S1600536810011918/wn2380sup1.cif

e-66-o1051-sup1.cif^{(22.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810011918/wn2380Isup2.hkl

e-66-o1051-Isup2.hkl^{(268.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 is the centroid of the C8–C13 benzene ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1O1⋯N1ⁱ	0.85 (2)	1.97 (2)	2.7475 (17)	151.7 (19)
C2—H2A⋯O2ⁱⁱ	0.93	2.58	3.3648 (17)	142
C13—H13A⋯O3ⁱⁱⁱ	0.93	2.56	3.4223 (17)	154
C18—H18B⋯O4ⁱⁱⁱ	0.96	2.60	3.514 (2)	160
C18—H18C⋯O1^iv	0.96	2.54	3.4753 (17)	163
C18—H18A⋯Cg1^v	0.96	2.89	3.5798 (16)	129
C20—H20B⋯Cg1	0.96	2.81	3.4764 (17)	127

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

Acknowledgments

NA, ASAR and HO gratefully acknowledge Universiti Sains Malaysia (USM) for funding the synthetic chemistry work under the USM Research University Grant (1001/PFARMASI/815026). NA thanks Universiti Sains Malaysia for the award of a postdoctoral fellowship. HKF and MMR thank Universiti Sains Malaysia for the Research University Golden Goose grant (No. 1001/PFIZIK/811012).

supplementary crystallographic information

Comment

Benzimidazole-based heterocycles are known to exhibit antihistamine (Lemura et al., 1986), immunosuppressive (Zhang et al., 2008), anti-inflammatory (Blythin et al., 1986), antiviral (Bonfanti et al., 2008) and antibacterial (Ozden et al., 2008) activities. In particular, substituted benzimidazole derivatives act as potential anticancer agents (Townsend et al., 1970). In view of their importance, the crystal structure determination of the title compound was carried out and the results are presented here.

All molecular geometric parameters in the title compound are within normal ranges and are comparable with those in related crystal structures (Arumugam, Abd Hamid et al. (2010); Arumugam, Abdul Rahim, Abd Hamid et al. (2010); Arumugam, Abdul Rahim, Osman et al. (2010)). The benzimidazole ring system (N1/N2/C1-C7) is planar with a maximum deviation of 0.047 (1) Å for atom C1. The dihedral angle between the benzimidazole ring system (N1/N2/C1-C7) and the attached benzene ring (C8-C13) is 88.44 (5)°.

In the crystal structure, molecules are connected by intermolecluar O1—H1O1···N1ⁱ, C2—H2A···O2ⁱⁱ, C13—H13A···O3ⁱⁱⁱ, C18—H18B···O4ⁱⁱⁱ and C18—H18C···O1^iv interactions (Table 1). These interactions link the molecules to form infinite one-dimensional chains along the b-axis (Fig. 2). The crystal structure is further stabilized by C—H···π interactions (Table 1), involving the C8-C13 (centroid Cg1) rings.

Experimental

The title compound was synthesised according to the previous procedure described by us (Arumugam, Abd Hamid et al. (2010); Arumugam, Abdul Rahim, Abd Hamid et al. (2010); Arumugam, Abdul Rahim, Osman et al. (2010)). The product was recrystallised from EtOAc to afford the title compound as colourless crystals.