1-Benzyl-1H-benzimidazol-2(3H)-one

The fused five- and six-membered rings in the title compound, C₁₄H₁₂N₂O, are essentially planar, the largest deviation from the mean plane being 0.023 (2) Å. The dihedral angle between the benzimidazole mean plane and the phenyl ring is 68.50 (6)°. In the crystal, each mol­ecule is linked to its symmetry equivalent created by a crystallographic inversion center by pairs of N—H⋯O hydrogen bonds, forming inversion dimers.

Related literature

For the biological activity of benzimidazole derivatives, see: Gravatt et al. (1994); Horton et al. (2003); Kim et al. (1996); Roth et al. (1997). For related structures, see: Ouzidan et al. (2011a,b).

Experimental

Crystal data

• C₁₄H₁₂N₂O

• M_r = 224.26

• Monoclinic, P 2₁ /n

• a = 13.8652 (7) Å

• b = 5.7975 (3) Å

• c = 14.9337 (7) Å

• β = 109.5346 (12)°

• V = 1131.33 (10) ų

• Z = 4

• Mo Kα radiation

• μ = 0.09 mm⁻¹

• T = 298 K

• 0.50 × 0.44 × 0.28 mm

Data collection

• Bruker CCD three-circle diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996) T_min = 0.959, T_max = 0.977

• 9007 measured reflections

• 3392 independent reflections

• 2514 reflections with I > 2σ(I)

• R_int = 0.020

Refinement

• R[F² > 2σ(F²)] = 0.045

• wR(F²) = 0.126

• S = 1.05

• 3392 reflections

• 166 parameters

• H-atom parameters constrained

• Δρ_max = 0.21 e Å⁻³

• Δρ_min = −0.19 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1^i	0.86	2.03	2.845 (1)	158
Symmetry code: (i) -x+1, -y+2, -z+1.

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP (Sheldrick, 2008); software used to prepare material for publication: WinGX (Farrugia, 1999).

Supporting information

S1. Comment

Benzimidazoles are very useful intermediates/subunits for the development of molecules of pharmaceutical or biological interest and its derivatives are an important class of bioactive molecules in the field of drugs and pharmaceuticals. Benzimidazole derivatives have found applications in diverse therapeutic areas including anti-ulcers, anti-hypertensives, anti-virals, anti-fungals, anti-cancers, (Gravatt et al. 1994; Horton et al. 2003; Kim et al. 1996; Roth et al. 1997).

As a continuation of our research work devoted to the development of substituted benzimidazol-2-one derivatives (Ouzidan et al., 2011a, 2011b), we report in this paper the synthesis of a new benzimidazol-2-one derivative by action of benzyl chloride with 1H-benzimidazol-2-one in the presence of a catalytic quantity of tetra-n-butylammonium bromide under mild conditions to furnish the title compound (Scheme 1).

The two fused five and six-membered rings are almost planar with the maximum deviation of 0.023 (2) Å from C2. The dihedral angle between the benzimidazole system and the phenyl ring is 68.50 (6)° (Fig.1). In the crystal structure each molecule is linked to its symmetry equivalent created by the crystallographic inversion center by N–H···O hydrogen bonds to form pseudo-dimers as shown in Fg.2.

Related literature

For the biological activity of benzimidazole derivatives, see: Gravatt et al. (1994); Horton et al. (2003); Kim et al. (1996); Roth et al. (1997). For related structures, see: Ouzidan et al. (2011a,b).

S2. Experimental

To 1H-benzimidazol-2-one (0.2 g, 1.5 mmol), potassium carbonate (0.41 g, 3 mmol) and tetra-n-butylammonium bromide (0.05 g, 0.15 mmol) in DMF (15 ml) was added benzyl chloride (0.34 ml, 3 mmol). Stirring was continued at room temperature for 6 h. The salt was removed by filtration and the filtrate concentrated under reduced pressure. The residue was separated by chromatography on a column of silica gel with ethyl acetate/hexane (1/2) as eluent. The compound was recrystallized from ethanol to give colorless crystals (yield: 12%).

S3. Refinement

H atoms were located in a difference map and treated as riding with C—H = 0.93 Å, and 0.97 Å for aromatic and methylene H atoms, respectively, and with U_iso(H) = 1.2 U_eq(C).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP (Sheldrick, 2008); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. : Molecular view of the title compound. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small circles of arbitrary radii.
	Fig. 2. : Formation of pseudo-dimers between two molecules by N–H···O hydrogen bonds (dashed lines).

1-Benzyl-1H-benzimidazol-2(3H)-one

Crystal data

C14H12N2O	F(000) = 472
Mr = 224.26	Dx = 1.317 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 3392 reflections
a = 13.8652 (7) Å	θ = 1.7–30.5°
b = 5.7975 (3) Å	µ = 0.09 mm^−1
c = 14.9337 (7) Å	T = 298 K
β = 109.5346 (12)°	Prism, colourless
V = 1131.33 (10) Å^3	0.50 × 0.44 × 0.28 mm
Z = 4

Data collection

Bruker CCD three-circle diffractometer	3392 independent reflections
Radiation source: fine-focus sealed tube	2514 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.020
ω scans	θmax = 30.5°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −18→19
Tmin = 0.959, Tmax = 0.977	k = −8→8
9007 measured reflections	l = −16→21

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.126	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0584P)^2 + 0.1866P] where P = (Fo^2 + 2Fc^2)/3
3392 reflections	(Δ/σ)max < 0.001
166 parameters	Δρmax = 0.21 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against all reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on all data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.59908 (7)	0.79068 (16)	0.53088 (6)	0.0462 (2)
N1	0.46509 (7)	0.82117 (17)	0.38695 (7)	0.0391 (2)
H1	0.4387	0.9497	0.3958	0.066 (5)*
C1	0.54932 (8)	0.72077 (19)	0.45072 (8)	0.0354 (2)
N2	0.56888 (7)	0.52373 (16)	0.40851 (7)	0.0350 (2)
C2	0.49440 (8)	0.49698 (19)	0.31953 (8)	0.0343 (2)
C3	0.47930 (10)	0.3259 (2)	0.25181 (9)	0.0429 (3)
H3	0.5232	0.2003	0.2611	0.050 (4)*
C4	0.39558 (11)	0.3498 (3)	0.16918 (9)	0.0513 (3)
H4	0.3834	0.2382	0.1220	0.060 (4)*
C5	0.32981 (10)	0.5368 (3)	0.15565 (9)	0.0510 (3)
H5	0.2745	0.5477	0.0995	0.058 (4)*
C6	0.34472 (10)	0.7081 (2)	0.22409 (9)	0.0455 (3)
H6	0.3002	0.8326	0.2151	0.056 (4)*
C7	0.42820 (9)	0.68586 (19)	0.30576 (8)	0.0357 (2)
C8	0.64791 (9)	0.3581 (2)	0.45689 (8)	0.0378 (2)
H8A	0.6173	0.2060	0.4513	0.044 (4)*
H8B	0.6744	0.3968	0.5239	0.041 (3)*
C11	0.73601 (8)	0.34906 (19)	0.41875 (8)	0.0354 (2)
C12	0.75053 (11)	0.1565 (2)	0.36992 (10)	0.0491 (3)
H12	0.7048	0.0339	0.3591	0.061 (5)*
C13	0.83286 (13)	0.1452 (3)	0.33705 (12)	0.0638 (4)
H13	0.8416	0.0160	0.3036	0.088 (6)*
C14	0.90122 (13)	0.3235 (3)	0.35368 (12)	0.0659 (4)
H14	0.9569	0.3145	0.3324	0.085 (6)*
C15	0.88757 (11)	0.5165 (3)	0.40199 (12)	0.0597 (4)
H15	0.9338	0.6382	0.4129	0.068 (5)*
C16	0.80491 (10)	0.5294 (2)	0.43437 (10)	0.0459 (3)
H16	0.7958	0.6601	0.4668	0.054 (4)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0430 (5)	0.0475 (5)	0.0452 (5)	−0.0005 (4)	0.0110 (4)	−0.0138 (4)
N1	0.0386 (5)	0.0356 (5)	0.0443 (5)	0.0044 (4)	0.0155 (4)	−0.0033 (4)
C1	0.0336 (5)	0.0348 (5)	0.0411 (6)	−0.0025 (4)	0.0171 (5)	−0.0040 (4)
N2	0.0330 (4)	0.0349 (5)	0.0367 (5)	0.0019 (4)	0.0114 (4)	−0.0035 (4)
C2	0.0326 (5)	0.0368 (5)	0.0347 (5)	−0.0011 (4)	0.0130 (4)	0.0000 (4)
C3	0.0447 (6)	0.0405 (6)	0.0429 (6)	0.0018 (5)	0.0137 (5)	−0.0065 (5)
C4	0.0515 (7)	0.0566 (8)	0.0422 (7)	−0.0042 (6)	0.0109 (6)	−0.0116 (6)
C5	0.0412 (6)	0.0656 (9)	0.0404 (6)	−0.0013 (6)	0.0060 (5)	0.0005 (6)
C6	0.0381 (6)	0.0500 (7)	0.0479 (7)	0.0064 (5)	0.0134 (5)	0.0065 (6)
C7	0.0346 (5)	0.0364 (5)	0.0395 (6)	−0.0003 (4)	0.0167 (5)	0.0006 (4)
C8	0.0389 (6)	0.0371 (6)	0.0384 (6)	0.0039 (4)	0.0141 (5)	0.0041 (5)
C11	0.0356 (5)	0.0365 (5)	0.0327 (5)	0.0070 (4)	0.0094 (4)	0.0053 (4)
C12	0.0516 (7)	0.0422 (7)	0.0547 (8)	0.0073 (6)	0.0195 (6)	−0.0022 (6)
C13	0.0697 (10)	0.0637 (9)	0.0675 (9)	0.0226 (8)	0.0354 (8)	−0.0002 (8)
C14	0.0551 (9)	0.0814 (11)	0.0728 (10)	0.0221 (8)	0.0367 (8)	0.0184 (9)
C15	0.0445 (7)	0.0656 (9)	0.0710 (10)	−0.0033 (7)	0.0221 (7)	0.0141 (8)
C16	0.0446 (7)	0.0432 (6)	0.0499 (7)	0.0009 (5)	0.0158 (5)	0.0008 (5)

Geometric parameters (Å, º)

O1—C1	1.2332 (14)	C6—H6	0.9300
N1—C1	1.3660 (15)	C8—C11	1.5114 (15)
N1—C7	1.3901 (15)	C8—H8A	0.9700
N1—H1	0.8600	C8—H8B	0.9700
C1—N2	1.3749 (14)	C11—C16	1.3824 (17)
N2—C2	1.3922 (14)	C11—C12	1.3845 (17)
N2—C8	1.4546 (14)	C12—C13	1.387 (2)
C2—C3	1.3815 (16)	C12—H12	0.9300
C2—C7	1.3991 (15)	C13—C14	1.368 (3)
C3—C4	1.3897 (19)	C13—H13	0.9300
C3—H3	0.9300	C14—C15	1.379 (2)
C4—C5	1.387 (2)	C14—H14	0.9300
C4—H4	0.9300	C15—C16	1.3869 (19)
C5—C6	1.3902 (19)	C15—H15	0.9300
C5—H5	0.9300	C16—H16	0.9300
C6—C7	1.3783 (17)
C1—N1—C7	110.31 (9)	N1—C7—C2	106.35 (10)
C1—N1—H1	124.8	N2—C8—C11	113.90 (9)
C7—N1—H1	124.8	N2—C8—H8A	108.8
O1—C1—N1	127.38 (11)	C11—C8—H8A	108.8
O1—C1—N2	125.88 (11)	N2—C8—H8B	108.8
N1—C1—N2	106.74 (10)	C11—C8—H8B	108.8
C1—N2—C2	109.46 (9)	H8A—C8—H8B	107.7
C1—N2—C8	123.52 (10)	C16—C11—C12	119.00 (11)
C2—N2—C8	126.56 (9)	C16—C11—C8	120.68 (11)
C3—C2—N2	131.39 (10)	C12—C11—C8	120.30 (11)
C3—C2—C7	121.52 (11)	C11—C12—C13	120.43 (14)
N2—C2—C7	107.09 (9)	C11—C12—H12	119.8
C2—C3—C4	117.10 (11)	C13—C12—H12	119.8
C2—C3—H3	121.5	C14—C13—C12	120.16 (14)
C4—C3—H3	121.5	C14—C13—H13	119.9
C5—C4—C3	121.38 (12)	C12—C13—H13	119.9
C5—C4—H4	119.3	C13—C14—C15	120.03 (14)
C3—C4—H4	119.3	C13—C14—H14	120.0
C4—C5—C6	121.48 (12)	C15—C14—H14	120.0
C4—C5—H5	119.3	C14—C15—C16	120.02 (14)
C6—C5—H5	119.3	C14—C15—H15	120.0
C7—C6—C5	117.27 (11)	C16—C15—H15	120.0
C7—C6—H6	121.4	C11—C16—C15	120.36 (13)
C5—C6—H6	121.4	C11—C16—H16	119.8
C6—C7—N1	132.40 (11)	C15—C16—H16	119.8
C6—C7—C2	121.25 (11)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^i	0.86	2.03	2.845 (1)	158

Symmetry code: (i) −x+1, −y+2, −z+1.