1,3,3-Trimethyl-1,2,3,4-tetra­hydro­pyrido[1,2-a]benzimidazol-1-ol

Sayed Hasan Mehdi; Rokiah Hashim; Raza Murad Ghalib; Chin Sing Yeap; Hoong-Kun Fun

doi:10.1107/S1600536810024487

. 2010 Jun 26;66(Pt 7):o1832. doi: 10.1107/S1600536810024487

1,3,3-Trimethyl-1,2,3,4-tetrahydropyrido[1,2-a]benzimidazol-1-ol

Sayed Hasan Mehdi ^a, Rokiah Hashim ^a, Raza Murad Ghalib ^a, Chin Sing Yeap ^b,^‡, Hoong-Kun Fun ^b,^*,^§

PMCID: PMC3006987 PMID: 21588036

Abstract

In the title compound, C₁₄H₁₈N₂O, the benzimidazole grouping is close to planar, with a maximum deviation of 0.042 Å; the six-membered non-aromatic ring adopts an envelope conformation. In the crystal structure, molecules are linked into infinite sheets lying parallel to the bc plane by O—H⋯N and C—H⋯O hydrogen bonds.

Related literature

For applications of benzimidazole derivatives, see: Horton et al. (2003 ▶); Insuasty et al. (2008a ▶,b ▶). For the preparation of the title compound, see: Grech et al. (1994 ▶). For ring conformations, see Cremer & Pople (1975 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₄H₁₈N₂O
M _r = 230.30
Monoclinic,
a = 9.615 (5) Å
b = 8.194 (4) Å
c = 15.965 (8) Å
β = 99.601 (12)°
V = 1240.2 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 100 K
0.38 × 0.12 × 0.07 mm

Data collection

Bruker APEXII DUO CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.971, T _max = 0.995
13460 measured reflections
3597 independent reflections
2612 reflections with I > 2σ(I)
R _int = 0.052

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.117
S = 1.02
3597 reflections
226 parameters
All H-atom parameters refined
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.25 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/S1600536810024487/hb5508sup1.cif

e-66-o1832-sup1.cif^{(19.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810024487/hb5508Isup2.hkl

e-66-o1832-Isup2.hkl^{(176.4KB, 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
O1—H1O1⋯N1ⁱ	0.97 (2)	1.84 (2)	2.803 (2)	174 (2)
C5—H5A⋯O1ⁱⁱ	0.962 (15)	2.499 (15)	3.216 (2)	131.3 (11)

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

Acknowledgments

SHM and RMG thank Universiti Sains Malaysia (USM) for the University Grant (1001/PTEKIND/8140152). HKF and CSY thank USM for the Research University Golden Goose Grant (1001/PFIZIK/811012). CSY also thanks USM for the award of a USM Fellowship.

supplementary crystallographic information

Comment

Benzimidazole derivatives are an important class of bioactive molecules and are well known due to their wide range of pharmacological activities as an anti-ulcers, anti-hypertensive, anti-viral, anti-fungal, anti-cancer, and anti-histaminic (Horton et al., 2003; Insuasty et al., 2008a, b) agents. Here we report the synthesis and the crystal structure of title compound.

In the title compound (Fig. 1), the benzimidazole group is essentially coplanar (N1/C1–C6/N2/C11) with the maximum deviation of 0.042 Å at atom C6. The N2/C7–C11 ring adopts an envelope conformation with Q=0.4933 (14) Å, θ=52.81 (15)° and φ=182.3 (2)° (Cremer & Pople, 1975).

In the crystal structure, the molecules are linked into infinite two-dimensional planes parallel to bc plane by the intermolecular O1—H1O1···N1 and C5—H5A···O1 hydrogen bonds (Fig. 2, Table 1).

Experimental

A mixture of o-phenylenediamine (0.108 g m) and dimedone (0.140 g m) in molar ratio 1:1 was refluxed in a mixture of acetic acid-ethanol (1:1 v/v) for 3 h (Grech et al., 1994). The reaction mixture was dried on rotavapor at low pressure and further fractionated successively with diethyl ether, chloroform and ethanol. The ethanol fraction was dried on rotavapor and the dry mass so obtained was crystallized in methanol:chloroform (1:1) mixture to give yellow needles of (I) (55%, m.p. 451 K).