2-(5,6-Dihydro­benzimidazo[1,2-c]quinazolin-6-yl)-5-meth­oxy­phenol

Naser Eltaher Eltayeb; Siang Guan Teoh; Suchada Chantrapromma; Hoong-Kun Fun

doi:10.1107/S1600536811034027

. 2011 Aug 27;67(Pt 9):o2410–o2411. doi: 10.1107/S1600536811034027

2-(5,6-Dihydrobenzimidazo[1,2-c]quinazolin-6-yl)-5-methoxyphenol

Naser Eltaher Eltayeb ^a,^b, Siang Guan Teoh ^a, Suchada Chantrapromma ^c,^‡, Hoong-Kun Fun ^d,^*,^§

PMCID: PMC3200720 PMID: 22058999

Abstract

In the title quinazoline derivative, C₂₁H₁₇N₃O₂, the benzimidazole unit makes dihedral angles of 8.29 (5) and 81.79 (5)° with the benzene rings of the quinazoline and methoxyphenol units, respectively. The nitrogen-containing six-membered ring adopts a half-chair conformation. In the crystal, the molecules are linked through O—H⋯N hydrogen bonds into screw chains along the b axis; adjacent chains are further connected by N—H⋯O hydrogen bonds, thereby forming a two-dimensional network lying parallel to the bc plane. Weak C—H⋯π and π⋯π interactions with centroid–centroid distances of 3.5258 (8) and 3.7184 (7) Å are present and N⋯O [2.6816 (15) and 3.0519 (15) Å] short contacts also occur.

Related literature

For background to benzoheterocyclic derivatives and their applications, see: Arienzo et al. (2007 ▶); Chassaing et al. (2008 ▶); Galarcei et al. (2008 ▶); Kumar & Rajput (2009 ▶); Kung et al. (2009 ▶); Podunavac-Kuzmanovic & Cvetkovic (2010 ▶); Via et al. (2001 ▶); Xue et al. (2011 ▶); Zhang et al. (2009 ▶). For related structures, see: Eltayeb et al. (2007 ▶, 2009 ▶, 2011a ▶,b ▶). For reference bond-length data, see: Allen et al. (1987 ▶). For ring conformations, see: Cremer & Pople (1975 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₂₁H₁₇N₃O₂
M _r = 343.38
Monoclinic,
a = 9.5408 (1) Å
b = 15.6503 (2) Å
c = 11.7609 (1) Å
β = 110.408 (1)°
V = 1645.87 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.28 × 0.25 × 0.22 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.974, T _max = 0.980
31713 measured reflections
6610 independent reflections
4637 reflections with I > 2σ(I)
R _int = 0.039

Refinement

R[F ² > 2σ(F ²)] = 0.059
wR(F ²) = 0.139
S = 1.05
6610 reflections
244 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.43 e Å⁻³
Δρ_min = −0.30 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 datablock(s) global, I. DOI: 10.1107/S1600536811034027/hb6371sup1.cif

e-67-o2410-sup1.cif^{(21.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811034027/hb6371Isup2.hkl

e-67-o2410-Isup2.hkl^{(323.5KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811034027/hb6371Isup3.cml

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

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

Cg4 is the centroid of the C15–C20 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H1N3⋯O2ⁱ	0.907 (19)	2.211 (19)	3.0519 (15)	153.8 (17)
O1—H1O1⋯N2ⁱⁱ	0.98 (2)	1.72 (2)	2.6816 (15)	168 (2)
C2—H2A⋯Cg4	0.95	2.85	3.6277 (16)	140

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank the Malaysian Government and Universiti Sains Malaysia for the RU research grant No. 1001/PKIMIA/815067. NEE thanks Universiti Sains Malaysia for a post-doctoral fellowship and the International University of Africa (Sudan) for providing study leave. The authors also thank the Universiti Sains Malaysia for the Research University grant No. 1001/PFIZIK/811160.

supplementary crystallographic information

Comment

Benzoheterocyclic derivatives have been used widely in the pharmaceutical industry and medicine due to their diverse pharmaceutical activities (Arienzo et al., 2007; Chassaing et al., 2008; Kumar et al., 2009; Kung et al., 2009; Podunavac-Kuzmanovic & Cvetkovic, 2010; Zhang et al., 2009) including inhibition against enteroviruses (Xue et al., 2011) and potent antitumor activity (Galarcei et al., 2008; Via et al., 2001). Due to their interesting activities, the benzimidazole and quinazoline scaffolds were selected for our ongoing structural studies (Eltayeb et al., 2007; 2009; 2011a; 2011b).

In the title compound (I) (Fig. 1), the benzimidazole ring system (C1–C7/N1–N2) is planar with the r.m.s. of 0.0086 (1) Å with the most deviation for atom C1 of 0.0183 (1) Å. The benzimidazole makes the dihedral angle of 8.29 (5)° with the C8–C13 benzene ring of the quinazoline moiety (C7–C14/N1/N3). The nitrogen six-membered ring adopts a half-chair conformation with the puckering parameter Q = 0.3941 (13) Å, θ = 59.34 (19)° and φ = 277.7 (2)° (Cremer & Pople, 1975). The orientation of the 5-methoxyphenol can be indicated by the dihedral angle between the phenol ring and benzimidazole of 81.79 (5)°. The methoxy substituted is slightly twisted from its attached benzene ring with the torsion angle C21–O2–C18–C19 = 8.93 (17)°. The bond lengths agree with the literature values (Allen et al., 1987).

In the crystal structure of (I) as shown Fig. 2, the molecules are linked through O—H···N hydrogen bonds (Table 1) into screw chains along the b axis. The adjacent screw chains are further connected by N—H···O hydrogen bonds (Table 1) forming the two-dimensional network parallel to the bc plane. The crystal is further stabilized by C—H···π weak interactions (Table 1). π···π interactions were also observed with centroid···centroid distances: Cg₁···Cg₃ⁱⁱⁱ = 3.7184 (7) Å and Cg₂···Cg₂^iv = 3.5258 (8) Å; Cg₁, Cg₂ and Cg₃ are the centroids of C1/C6/C7/N1–N2, C1–C6 and C8–C13 rings, respectively (symmetry codes: (iii) = -x, 1-y, -z and (iv) = -x, 1-y 1-z). N···O[2.6816 (15) and 3.0519 (15) Å] short contacts were also observed.

Experimental

The title compound was synthesized by adding 2-hydroxy-4-methoxybenzaldehyde (0.304 g, 2.0 mmol) to a solution of 2-(2-aminophenyl)-1H-benzimidazole (0.418 g, 2.0 mmol) in ethanol (30 mL). The mixture was refluxed with stirring for 2 hrs. The color of the resulting solution was pale-yellow. Pale-yellow blocks were formed after three weeks of slow evaporation of ethanol at room temperature.