3,4-Dimethyl-1H-1,2,4-triazepino[2,3-a]benzimidazol-2(3H)-one

Saber, A.; Al Subari, A.; Zouihri, H.; Essassi, E.M.; Ng, S.W.

doi:10.1107/S1600536810013498

organic compounds

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Volume 66| Part 5| May 2010| Page o1093

https://doi.org/10.1107/S1600536810013498

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3,4-Dimethyl-1H-1,2,4-triazepino[2,3-a]benzimidazol-2(3H)-one

Asmae Saber,^a Abdusalam Al Subari,^a Hafid Zouihri,^b El Mokhtar Essassi ^a and Seik Weng Ng ^c ^*

^aLaboratoire de Chimie Organique Hétérocyclique, Pôle de Compétences Pharmacochimie, Université Mohammed V-Agdal, BP 1014 Avenue Ibn Batout, Rabat, Morocco, ^bCNRST Division UATRS, Angle Allal Fassi/FAR, BP 8027 Hay Riad, 10000 Rabat, Morocco, and ^cDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: seikweng@um.edu.my

(Received 9 April 2010; accepted 12 April 2010; online 17 April 2010)

In the molecule of the title compound, C₁₂H₁₂N₄O, a C atom and an N atom of the benzimidazole fused-ring portion are part of a seven-membered ring; this ring adopts a boat-shaped conformation (with the fused-ring atoms representing the stern and the sp³-hybridized C atom the prow). The amino group is a hydrogen-bond donor to the imidazole group of an inversion-related molecule, the pair of N—H⋯N hydrogen bonds giving rise to a hydrogen-bonded dimer.

Related literature

For the synthesis, see: Romano et al. (1988 ).

Experimental

Crystal data

C₁₂H₁₂N₄O
M_r = 228.26
Monoclinic, P 2₁ /c
a = 7.2899 (3) Å
b = 14.4888 (5) Å
c = 10.9932 (4) Å
β = 104.314 (1)°
V = 1125.08 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.21 × 0.19 × 0.16 mm

Data collection

Bruker X8 APEXII diffractometer
14670 measured reflections
3095 independent reflections
1823 reflections with I > 2σ(I)
R_int = 0.034

Refinement

R[F² > 2σ(F²)] = 0.049
wR(F²) = 0.157
S = 1.01
3095 reflections
160 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.24 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⋯N4ⁱ	0.86 (1)	2.01 (1)	2.867 (2)	174 (2)
Symmetry code: (i) -x+1, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2008 ); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810013498/si2255sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810013498/si2255Isup2.hkl

checkCIF report

Comment top

1,2-Diaminobenzimidazoles react with β-dicarbonyl compounds to form 1,2,4-triazepino[2,3-a]benzimidazoles (Romano et al., 1988), a class of compounds used in the treatment of neuronal disorders. The title compound (Scheme I, Fig. 1) was synthesized from 2-aminobenzimidazole and ethyl 2-methylacetoacetate. A carbon atom and a nitrogen atom of the benzimidazole fused-ring portion are part of a seven-membered ring; this ring adopts a boat-shaped conformation (with the fused-ring atoms representing the stern and the sp³-hybridized carbon atom the prow). Its methyl substitent occupies a quasi-equatorial position. The amino group is hydrogen-bond donor to the imidazole group (Table 1) of an inversion-related molecule, the pair of N—H···N hydrogen bonds (Fig. 1) giving rise to a hydrogen-bonded dimer.

Related literature top

For the synthesis, see: Romano et al. (1988).

Experimental top

2-Aminobenzimidazole (1 g, 6.75 mmol) and a slight excess of ethyl 2-methylacetoacetate (1.69 ml) were refluxed in xylene (10 ml) and acetic acid (0.5 ml) for 3 hours. The mixture was concentrated under reduced pressure and the resulting residue was recrystallized from ethanol. Brown crystals were isolated when the solvent was allowed to evaporate.

Structure description top

For the synthesis, see: Romano et al. (1988).

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of the hydrogen-bonded dimeric structure of C₁₂H₁₂N₄O at the 50% probability level; hydrogen atoms are drawn as arbitrary radius. Symmetry code for the inversion related molecule: 1 - x, 1 - y, 1 - z.

3,4-Dimethyl-1H-1,2,4-triazepino[2,3-a]benzimidazol- 2(3H)-one top

Crystal data top

C₁₂H₁₂N₄O	F(000) = 480
M_r = 228.26	D_x = 1.348 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3188 reflections
a = 7.2899 (3) Å	θ = 2.4–24.8°
b = 14.4888 (5) Å	µ = 0.09 mm⁻¹
c = 10.9932 (4) Å	T = 293 K
β = 104.314 (1)°	Prism, brown
V = 1125.08 (7) Å³	0.21 × 0.19 × 0.16 mm
Z = 4

Data collection top

Bruker X8 APEXII diffractometer	1823 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.034
Graphite monochromator	θ_max = 29.4°, θ_min = 2.4°
φ and ω scans	h = −9→10
14670 measured reflections	k = −20→19
3095 independent reflections	l = −15→13

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.157	H atoms treated by a mixture of independent and constrained refinement
S = 1.01	w = 1/[σ²(F_o²) + (0.0742P)² + 0.1838P] where P = (F_o² + 2F_c²)/3
3095 reflections	(Δ/σ)_max < 0.001
160 parameters	Δρ_max = 0.24 e Å⁻³
1 restraint	Δρ_min = −0.19 e Å⁻³

Crystal data top

C₁₂H₁₂N₄O	V = 1125.08 (7) Å³
M_r = 228.26	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 7.2899 (3) Å	µ = 0.09 mm⁻¹
b = 14.4888 (5) Å	T = 293 K
c = 10.9932 (4) Å	0.21 × 0.19 × 0.16 mm
β = 104.314 (1)°

Data collection top

Bruker X8 APEXII diffractometer	1823 reflections with I > 2σ(I)
14670 measured reflections	R_int = 0.034
3095 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.049	1 restraint
wR(F²) = 0.157	H atoms treated by a mixture of independent and constrained refinement
S = 1.01	Δρ_max = 0.24 e Å⁻³
3095 reflections	Δρ_min = −0.19 e Å⁻³
160 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.40956 (19)	0.51793 (12)	0.14398 (13)	0.0762 (5)
N1	0.5626 (2)	0.53766 (12)	0.34574 (15)	0.0574 (4)
H1	0.486 (3)	0.5002 (13)	0.3696 (19)	0.075 (7)*
N2	0.95622 (19)	0.59291 (9)	0.32932 (14)	0.0508 (4)
N3	0.86966 (19)	0.60627 (9)	0.42759 (13)	0.0475 (4)
N4	0.6799 (2)	0.58224 (10)	0.55706 (13)	0.0552 (4)
C1	0.6977 (2)	0.57641 (11)	0.44172 (16)	0.0488 (4)
C2	0.5294 (2)	0.55903 (14)	0.22125 (17)	0.0569 (5)
C3	0.6491 (2)	0.63705 (13)	0.18892 (16)	0.0551 (5)
H3	0.6428	0.6886	0.2454	0.066*
C4	0.8529 (2)	0.60475 (11)	0.21815 (17)	0.0498 (4)
C5	0.5699 (3)	0.67076 (16)	0.05638 (19)	0.0797 (7)
H5A	0.6472	0.7202	0.0387	0.120*
H5B	0.4429	0.6926	0.0475	0.120*
H5C	0.5692	0.6210	−0.0014	0.120*
C6	0.9446 (3)	0.58710 (16)	0.11287 (19)	0.0694 (6)
H6A	1.0719	0.5659	0.1463	0.104*
H6B	0.9466	0.6432	0.0667	0.104*
H6C	0.8742	0.5409	0.0580	0.104*
C7	0.9748 (2)	0.62947 (10)	0.54769 (16)	0.0486 (4)
C8	1.1602 (3)	0.65870 (13)	0.59037 (19)	0.0636 (5)
H8	1.2399	0.6664	0.5369	0.076*
C9	1.2194 (3)	0.67573 (16)	0.7180 (2)	0.0790 (7)
H9	1.3432	0.6950	0.7517	0.095*
C10	1.0993 (4)	0.66492 (16)	0.7969 (2)	0.0780 (7)
H10	1.1444	0.6782	0.8819	0.094*
C11	0.9147 (3)	0.63502 (14)	0.75350 (18)	0.0653 (5)
H11	0.8348	0.6279	0.8070	0.078*
C12	0.8542 (3)	0.61603 (11)	0.62561 (16)	0.0516 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0480 (8)	0.1131 (12)	0.0627 (9)	−0.0193 (7)	0.0049 (6)	−0.0313 (8)
N1	0.0401 (8)	0.0756 (10)	0.0538 (9)	−0.0152 (7)	0.0068 (7)	−0.0171 (7)
N2	0.0385 (7)	0.0536 (8)	0.0580 (9)	−0.0022 (6)	0.0074 (7)	−0.0016 (6)
N3	0.0368 (7)	0.0521 (8)	0.0487 (8)	−0.0038 (6)	0.0012 (6)	−0.0036 (6)
N4	0.0461 (8)	0.0639 (9)	0.0520 (9)	−0.0080 (7)	0.0055 (7)	−0.0121 (7)
C1	0.0378 (8)	0.0540 (9)	0.0505 (9)	−0.0027 (7)	0.0035 (7)	−0.0103 (7)
C2	0.0349 (9)	0.0763 (12)	0.0565 (10)	0.0011 (8)	0.0056 (8)	−0.0202 (9)
C3	0.0468 (10)	0.0591 (10)	0.0536 (10)	0.0051 (8)	0.0014 (8)	−0.0080 (8)
C4	0.0404 (9)	0.0497 (9)	0.0563 (10)	−0.0035 (7)	0.0066 (8)	−0.0038 (7)
C5	0.0758 (15)	0.0797 (14)	0.0688 (13)	0.0114 (11)	−0.0103 (11)	−0.0030 (11)
C6	0.0578 (12)	0.0891 (15)	0.0640 (12)	−0.0009 (10)	0.0202 (10)	−0.0015 (10)
C7	0.0439 (9)	0.0417 (8)	0.0517 (9)	−0.0036 (7)	−0.0045 (8)	0.0010 (7)
C8	0.0482 (10)	0.0662 (11)	0.0657 (11)	−0.0128 (8)	−0.0065 (9)	0.0088 (9)
C9	0.0628 (13)	0.0825 (14)	0.0724 (14)	−0.0247 (11)	−0.0200 (11)	0.0067 (11)
C10	0.0816 (16)	0.0786 (14)	0.0575 (12)	−0.0199 (11)	−0.0137 (11)	−0.0014 (10)
C11	0.0708 (13)	0.0655 (11)	0.0521 (10)	−0.0082 (10)	0.0009 (9)	−0.0061 (8)
C12	0.0501 (10)	0.0467 (9)	0.0507 (9)	−0.0036 (7)	−0.0012 (8)	−0.0047 (7)

Geometric parameters (Å, º) top

O1—C2	1.213 (2)	C5—H5B	0.9600
N1—C2	1.365 (2)	C5—H5C	0.9600
N1—C1	1.373 (2)	C6—H6A	0.9600
N1—H1	0.864 (9)	C6—H6B	0.9600
N2—C4	1.279 (2)	C6—H6C	0.9600
N2—N3	1.393 (2)	C7—C8	1.383 (2)
N3—C1	1.371 (2)	C7—C12	1.385 (3)
N3—C7	1.394 (2)	C8—C9	1.384 (3)
N4—C1	1.309 (2)	C8—H8	0.9300
N4—C12	1.396 (2)	C9—C10	1.386 (3)
C2—C3	1.523 (3)	C9—H9	0.9300
C3—C5	1.510 (3)	C10—C11	1.382 (3)
C3—C4	1.515 (2)	C10—H10	0.9300
C3—H3	0.9800	C11—C12	1.393 (2)
C4—C6	1.495 (3)	C11—H11	0.9300
C5—H5A	0.9600

C2—N1—C1	126.41 (17)	H5A—C5—H5C	109.5
C2—N1—H1	118.6 (14)	H5B—C5—H5C	109.5
C1—N1—H1	114.7 (14)	C4—C6—H6A	109.5
C4—N2—N3	116.74 (14)	C4—C6—H6B	109.5
C1—N3—N2	130.27 (13)	H6A—C6—H6B	109.5
C1—N3—C7	105.84 (14)	C4—C6—H6C	109.5
N2—N3—C7	121.30 (14)	H6A—C6—H6C	109.5
C1—N4—C12	104.53 (15)	H6B—C6—H6C	109.5
N4—C1—N3	113.68 (14)	C8—C7—C12	123.37 (17)
N4—C1—N1	123.18 (16)	C8—C7—N3	131.12 (19)
N3—C1—N1	122.98 (16)	C12—C7—N3	105.50 (14)
O1—C2—N1	120.60 (19)	C7—C8—C9	115.6 (2)
O1—C2—C3	123.76 (18)	C7—C8—H8	122.2
N1—C2—C3	115.63 (14)	C9—C8—H8	122.2
C5—C3—C4	115.20 (18)	C8—C9—C10	121.89 (19)
C5—C3—C2	111.16 (15)	C8—C9—H9	119.1
C4—C3—C2	108.05 (14)	C10—C9—H9	119.1
C5—C3—H3	107.4	C11—C10—C9	122.06 (19)
C4—C3—H3	107.4	C11—C10—H10	119.0
C2—C3—H3	107.4	C9—C10—H10	119.0
N2—C4—C6	116.53 (16)	C10—C11—C12	116.7 (2)
N2—C4—C3	124.01 (16)	C10—C11—H11	121.7
C6—C4—C3	119.45 (16)	C12—C11—H11	121.7
C3—C5—H5A	109.5	C7—C12—C11	120.37 (17)
C3—C5—H5B	109.5	C7—C12—N4	110.36 (15)
H5A—C5—H5B	109.5	C11—C12—N4	129.27 (19)
C3—C5—H5C	109.5

C4—N2—N3—C1	45.3 (2)	C5—C3—C4—C6	−14.2 (2)
C4—N2—N3—C7	−155.63 (15)	C2—C3—C4—C6	110.73 (19)
C12—N4—C1—N3	−1.68 (19)	C1—N3—C7—C8	176.13 (18)
C12—N4—C1—N1	173.69 (17)	N2—N3—C7—C8	12.6 (3)
N2—N3—C1—N4	164.44 (16)	C1—N3—C7—C12	−2.84 (17)
C7—N3—C1—N4	2.94 (19)	N2—N3—C7—C12	−166.39 (14)
N2—N3—C1—N1	−10.9 (3)	C12—C7—C8—C9	−1.1 (3)
C7—N3—C1—N1	−172.44 (16)	N3—C7—C8—C9	−179.90 (18)
C2—N1—C1—N4	152.30 (18)	C7—C8—C9—C10	−0.6 (3)
C2—N1—C1—N3	−32.8 (3)	C8—C9—C10—C11	1.2 (4)
C1—N1—C2—O1	177.59 (18)	C9—C10—C11—C12	0.0 (3)
C1—N1—C2—C3	−3.3 (3)	C8—C7—C12—C11	2.3 (3)
O1—C2—C3—C5	13.2 (3)	N3—C7—C12—C11	−178.66 (16)
N1—C2—C3—C5	−165.91 (17)	C8—C7—C12—N4	−177.09 (16)
O1—C2—C3—C4	−114.2 (2)	N3—C7—C12—N4	1.99 (18)
N1—C2—C3—C4	66.8 (2)	C10—C11—C12—C7	−1.6 (3)
N3—N2—C4—C6	−177.91 (15)	C10—C11—C12—N4	177.58 (18)
N3—N2—C4—C3	3.5 (2)	C1—N4—C12—C7	−0.27 (19)
C5—C3—C4—N2	164.30 (17)	C1—N4—C12—C11	−179.55 (19)
C2—C3—C4—N2	−70.7 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N4ⁱ	0.86 (1)	2.01 (1)	2.867 (2)	174 (2)

Symmetry code: (i) −x+1, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₂H₁₂N₄O
M_r	228.26
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	7.2899 (3), 14.4888 (5), 10.9932 (4)
β (°)	104.314 (1)
V (Å³)	1125.08 (7)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.21 × 0.19 × 0.16

Data collection
Diffractometer	Bruker X8 APEXII diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	14670, 3095, 1823
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.691

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.157, 1.01
No. of reflections	3095
No. of parameters	160
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.24, −0.19

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N4ⁱ	0.86 (1)	2.01 (1)	2.867 (2)	174 (2)

Symmetry code: (i) −x+1, −y+1, −z+1.

Acknowledgements

We thank Université Mohammed V-Agdal and the University of Malaya for supporting this study.

References

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