2-Meth­oxy-6-(6-methyl-1H-benzimid­azol-2-yl)phenol

Naser Eltaher Eltayeb; Siang Guan Teoh; Ching Kheng Quah; Hoong-Kun Fun; Rohana Adnan

doi:10.1107/S1600536809022478

. 2009 Jun 17;65(Pt 7):o1613–o1614. doi: 10.1107/S1600536809022478

2-Methoxy-6-(6-methyl-1H-benzimidazol-2-yl)phenol

Naser Eltaher Eltayeb ^a,^‡, Siang Guan Teoh ^a, Ching Kheng Quah ^b,^§, Hoong-Kun Fun ^b,^*,^¶, Rohana Adnan ^a

PMCID: PMC2969490 PMID: 21582885

Abstract

In the title molecule, C₁₅H₁₄N₂O₂, the substituted benzene ring forms a dihedral angle of 4.15 (1)° with the benzimidazole ring system. An intramolecular O—H⋯N hydrogen bond generates an S(6) ring motif. In the solid state, molecules are linked into chains along the [001] via intermolecular bifurcated N—H⋯(O,O) hydrogen bonds, which generate R ₁ ²(5) ring motifs. The crystal packing is also consolidated by C—H⋯π interactions, and π–π stacking interactions between the imidazole and substituted benzene rings [centroid–centroid distance = 3.5746 (13) Å]. The methyl group attached to the benzimidazole ring system is disordered over two positions with occupancies of 0.587 (6) and 0.413 (6), suggesting 180° rotational disorder for the benzimidazole group.

Related literature

For the biological activity of benzimidazole derivatives, see: Minoura et al. (2004 ▶); Pawar et al. (2004 ▶); Tomei et al. (2003 ▶); Rao et al. (2003 ▶); Demirayak et al. (2002 ▶). For related structures, see: Eltayeb et al. (2007a ▶,b ▶,c ▶); Yeap et al. (2009 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For bond-length data, see: Allen et al. (1987 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₅H₁₄N₂O₂
M _r = 254.28
Tetragonal,
a = 14.4118 (2) Å
c = 12.0995 (2) Å
V = 2513.07 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.35 × 0.27 × 0.24 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.969, T _max = 0.978
28200 measured reflections
2215 independent reflections
1725 reflections with I > 2σ(I)
R _int = 0.033

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.156
S = 1.08
2215 reflections
193 parameters
6 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.17 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/S1600536809022478/ci2825sup1.cif

e-65-o1613-sup1.cif^{(19.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809022478/ci2825Isup2.hkl

e-65-o1613-Isup2.hkl^{(109KB, 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
N1—H1N⋯O1ⁱ	0.92 (4)	2.03 (3)	2.919 (3)	164 (2)
N1—H1N⋯O2ⁱ	0.92 (4)	2.58 (3)	3.168 (3)	123 (2)
O1—H1O⋯N2	0.97 (3)	1.61 (3)	2.572 (3)	167 (3)
C14—H14B⋯Cg1ⁱⁱ	0.96	2.95	3.840 (3)	154

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Symmetry codes: (i) Inline graphic ; (ii) . Cg1 is the centroid of the C8–C13 benzene ring.

Acknowledgments

The authors thank the Malaysian Government, the Ministry of Science, Technology and Innovation (MOSTI) and Universiti Sains Malaysia (USM) for the E-Science Fund and RU research grants (Nos. PKIMIA/613308, PKIMIA/815002, and PKIMIA/811120). HKF and CKQ thank USM for a Research University Golden Goose grant (No. 1001/PFIZIK/811012). CKQ thanks USM for a research fellowship. The International University of Africa (Sudan) is acknowledged for providing study leave to NEE.

supplementary crystallographic information

Comment

The synthesis of benzimidazoles has received much attention owing to the varied biological activity such as antidiabetic (Minoura et al., 2004), antimicrobial, antifungal (Pawar et al., 2004), antiviral (Tomei et al., 2003), antiHIV (Rao et al., 2003), and anticancer (Demirayak et al., 2002) properties exhibited by a number of derivatives of these compounds. Previously we reported crystal structures of 4-allyl-2-[1-(5-allyl-2-hydroxy-3-methoxybenzyl)-1H-benzimidazol-2-yl]-6- methoxyphenol (Eltayeb et al., 2007a), 2-(2-methoxynaphthalen-1-yl)-1- [(2-methoxynaphthalen-1-yl)methyl]-1H-benzimidazole (Eltayeb et al., 2007b) and 2-(benzimidazol-2-yl)-6-methoxyphenol (Eltayeb et al., 2007c). Owing to the biological importance of the attached benzimidazole ring system, we report here the single-crystal X-ray diffraction study of 2-methoxy-6-(6-methyl-1H-benzimidazol-2-yl)phenol.

The bond lengths (Allen et al., 1987) and angles in the title molecule (Fig. 1) are normal and are comparable to those observed in a closely related structure (Yeap et al., 2009). The dihedral angle between the C8-C13 and N1/N2/C1-C7 rings is 4.15 (1)°. The molecular structure is stabilized by an intramolecular O1—H1O···N2 hydrogen bond which generates an S(6) ring motif (Bernstein et al., 1995).

In the solid state, the molecules are linked via intermolecular N1—H1N···O1 and N1—H1N···O2 bifurcated donor bonds into chains along the [001] (Fig. 2). These hydrogen bonds form an R₁²(5) ring motif. The crystal packing is consolidated by C—H···π (Table 1) interactions involving the C8-C13 benzene ring, and π–π stacking interactions between the C8—C13 (centroid Cg1) ring at (3/2-x, 1/2-y, z) and the N1/C1/C6/N2/C7 (centroid Cg2) ring at (x, y, z), with a Cg1···Cg2 distance of 3.5746 (13) Å.

Experimental

To a solution of 4-methyl-1,2-phenylenediamine (0.244 g, 2 mmol) in ethanol (30 ml) was added 3-methoxysalicylaldehyde (0.604 g, 4 mmol). The mixture was refluxed with stirring for half an hour. The resultant red solution was filtered. The red powder obtained was dissolved in dichloromethane. Crystals suitable for XRD were formed after several days of slow evaporation of solvent at room temperature.