9-Ethyl-6-methyl-7H-1,2,4-triazolo[4,3-b][1,2,4]triazepin-8(9H)-one

El Bakri, Y.; Harmaoui, A.; Essassi, E.M.; Saadi, M.; El Ammari, L.

doi:10.1107/S2414314616018976

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 12| December 2016| x161897

https://doi.org/10.1107/S2414314616018976

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9-Ethyl-6-methyl-7H-1,2,4-triazolo[4,3-b][1,2,4]triazepin-8(9H)-one

Youness El Bakri,^a Abdallah Harmaoui,^a ^* El Mokhtar Essassi,^a Mohamed Saadi ^b and Lahcen El Ammari ^b

^aLaboratoire de Chimie Organique Hétérocyclique URAC 21, Pôle de Compétences Pharmacochimie, Mohammed V University in Rabat, BP 1014 Avenue Ibn Batouta, Rabat , Morocco, and ^bLaboratoire de Chimie du Solide Appliquée, Faculty of Sciences, Mohammed V University in Rabat, Avenue Ibn Battouta, BP 1014, Rabat, Morocco
^*Correspondence e-mail: a_harmaoui@yahoo.fr

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 26 November 2016; accepted 27 November 2016; online 9 December 2016)

In the title compound, C₈H₁₁N₅O, the triazepine ring displays a boat conformation. Its mean plane is inclined to the triazole ring by 22.10 (9)°. In the crystal, molecules are linked by C—H⋯O hydrogen bonds to form chains parallel to the b-axis direction. Inversion-related chains are linked via offset π–π interactions between the triazole rings, forming ribbons propagating in the b-axis direction. The terminal CH₃ group is disordered over two sets of sites, with a refined occupancy ratio of 0.48 (6):0.52 (6).

Keywords: crystal structure; triazole; triazepin-8(9H)-one; hydrogen bonding; offset π–π interactions.

CCDC reference: 1519451

Structure description

1,2,4-Triazepine derivatives are useful in the treatment of HIV infections (Zhao et al., 2005 ). It has been shown that heterocycles attached to a seven-membered ring possess important biological properties (Basile et al., 1989 ; Gupta et al., 2011 ). In a continuation of our studies on 1,2,4-triazolo[1,2,4]triazepine derivatives (Essassi et al., 1977 ; Harmaoui et al., 2015 ; Zemama et al., 2009 ), we report herein on the synthesis and crystal structure of the title compound.

The molecule of the title compound, Fig. 1, is built up from a two fused rings with methyl and ethyl substituents. The triazepine ring (N1–N3/C1–C4) adopts a boat conformation, as indicated by the total puckering amplitude Q_T = 0.8176 (15) Å and the spherical polar angles θ₂ = 74.44 (11)° with φ₂ = −100.9 (2)° and φ₃ = −160.6 (4)°. The mean plane through the triazepine ring makes a dihedral angle of 22.10 (9)° with the triazole ring (N2/N4/N5/C4/C5).

Figure 1
A view of the molecular structure of the title compound, showing the atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

In the crystal, molecules are linked by C5—H5⋯O1ⁱ hydrogen bonds to form chains parallel to the b axis (Table 1 and Fig. 2). Inversion-related chains are linked by offset π–π interactions between triazole rings [Cg⋯Cgⁱⁱ = 3.581 (1) Å; Cg is the centroid of the N2/N4/N5/C4/C5 ring, interplanar distance = 3.150 (1) Å, slippage = 1.703 Å, symmetry code: (ii) −x + 1, −y + 1, −z + 2], forming ribbons propagating in the b-axis direction (Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O1ⁱ	0.93	2.44	3.280 (2)	151
Symmetry code: (i) x, y+1, z.

Figure 2
Crystal packing for the title compound, viewed normal to (101). The C—H⋯O hydrogen bonds (see Table 1

) and π–π interactions are shown as cyan and black dashed lines, respectively.

Synthesis and crystallization

To a solution of 6-methyl-7H-[1,2,4]triazolo[4,3-b][1,2,4] triazepin-8(9H)-one (1 g, 0.06 mol) in 30 ml of sodium methoxide (prepared from 30 ml of methanol and 0.15 g of sodium) was added 1 g (0.007 mol) of ethyl iodide, and the mixture was heated for 5 h. The solution was then concentrated to dryness under reduced pressure and the residue extracted with chloroform. The compound isolated was chromatographed on a silica column (eluent: chloroform/ethanol 95:5 v/v) and recrystallized from ethanol solution to give colourless crystals of the title compound (yield 70%).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The terminal atom of the ethyl group (C8) is disordered over two sets of sites (C8A:C8B), with a refined occupancy ratio of 0.48 (6):0.52 (6).

Table 2
Experimental details

Crystal data
Chemical formula	C₈H₁₁N₅O
M_r	193.22
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	296
a, b, c (Å)	7.8989 (3), 8.0880 (3), 8.2052 (3)
α, β, γ (°)	90.297 (2), 113.319 (2), 98.488 (2)
V (Å³)	474.94 (3)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.10
Crystal size (mm)	0.37 × 0.32 × 0.27

Data collection
Diffractometer	Bruker X8 APEX
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.595, 0.747
No. of measured, independent and observed [I > 2σ(I)] reflections	14339, 2105, 1746
R_int	0.027
(sin θ/λ)_max (Å⁻¹)	0.641

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.133, 1.04
No. of reflections	2105
No. of parameters	137
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.32, −0.17
Computer programs: APEX2 and SAINT (Bruker, 2009 ), SHELXT2014 (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ), ORTEP-3 for Windows (Farrugia, 2012 ), Mercury (Macrae et al., 2008 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 1519451

Crystal structure: contains datablocks I, Global. DOI: https://doi.org/10.1107/S2414314616018976/su4101sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314616018976/su4101Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314616018976/su4101Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015b) and publCIF (Westrip, 2010).

9-Ethyl-6-methyl-7H-1,2,4-triazolo[4,3-b][1,2,4]triazepin-8(9H)-one top

Crystal data top

C₈H₁₁N₅O	Z = 2
M_r = 193.22	F(000) = 204
Triclinic, P1	D_x = 1.351 Mg m⁻³
a = 7.8989 (3) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.0880 (3) Å	Cell parameters from 2105 reflections
c = 8.2052 (3) Å	θ = 2.6–27.1°
α = 90.297 (2)°	µ = 0.10 mm⁻¹
β = 113.319 (2)°	T = 296 K
γ = 98.488 (2)°	Block, colourless
V = 474.94 (3) Å³	0.37 × 0.32 × 0.27 mm

Data collection top

Bruker X8 APEX diffractometer	2105 independent reflections
Radiation source: fine-focus sealed tube	1746 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.027
φ and ω scans	θ_max = 27.1°, θ_min = 2.6°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −10→10
T_min = 0.595, T_max = 0.747	k = −10→10
14339 measured reflections	l = −10→10

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)] = 0.045	Hydrogen site location: mixed
wR(F²) = 0.133	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0656P)² + 0.1549P] where P = (F_o² + 2F_c²)/3
2105 reflections	(Δ/σ)_max < 0.001
137 parameters	Δρ_max = 0.32 e Å⁻³
0 restraints	Δρ_min = −0.17 e Å⁻³

Special details top

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

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
N1	0.29573 (18)	0.49763 (16)	0.51599 (17)	0.0436 (3)
N2	0.43326 (18)	0.52817 (15)	0.68976 (17)	0.0391 (3)
N3	0.50084 (18)	0.25055 (16)	0.78018 (17)	0.0432 (3)
N4	0.6626 (2)	0.67889 (18)	0.9111 (2)	0.0534 (4)
N5	0.67342 (19)	0.51047 (17)	0.93918 (18)	0.0476 (3)
O1	0.2994 (2)	0.00760 (15)	0.6764 (2)	0.0695 (4)
C1	0.3253 (2)	0.15975 (19)	0.6984 (2)	0.0451 (4)
C2	0.1666 (2)	0.2584 (2)	0.6363 (2)	0.0449 (4)
H2A	0.0489	0.1818	0.5931	0.054*
H2B	0.1728	0.3279	0.7358	0.054*
C3	0.1734 (2)	0.36744 (19)	0.4908 (2)	0.0409 (3)
C4	0.5351 (2)	0.42416 (18)	0.80585 (19)	0.0384 (3)
C5	0.5207 (2)	0.6849 (2)	0.7627 (2)	0.0496 (4)
H5	0.4836	0.7833	0.7128	0.059*
C6	0.0294 (2)	0.3234 (2)	0.3070 (2)	0.0566 (5)
H6A	0.0378	0.2065	0.2764	0.085*
H6B	0.0458	0.4039	0.2286	0.085*
H6C	−0.0949	0.3130	0.3069	0.085*
C7	0.6598 (3)	0.1615 (2)	0.8760 (3)	0.0567 (5)
H7A	0.7223	0.2094	0.9977	0.068*
H7B	0.6107	0.0450	0.8796	0.068*
C8A	0.790 (3)	0.168 (3)	0.802 (3)	0.086 (3)	0.48 (6)
H8A1	0.8876	0.1077	0.8717	0.129*	0.48 (6)
H8A2	0.7308	0.1178	0.6827	0.129*	0.48 (6)
H8A3	0.8425	0.2825	0.8010	0.129*	0.48 (6)
C8B	0.759 (3)	0.126 (3)	0.750 (4)	0.081 (4)	0.52 (6)
H8B1	0.8618	0.0680	0.8119	0.122*	0.52 (6)
H8B2	0.6713	0.0572	0.6464	0.122*	0.52 (6)
H8B3	0.8047	0.2297	0.7138	0.122*	0.52 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0447 (7)	0.0447 (7)	0.0404 (7)	0.0115 (6)	0.0146 (6)	0.0063 (5)
N2	0.0414 (7)	0.0349 (6)	0.0414 (7)	0.0077 (5)	0.0165 (5)	0.0026 (5)
N3	0.0437 (7)	0.0382 (7)	0.0468 (7)	0.0130 (5)	0.0150 (6)	0.0029 (5)
N4	0.0534 (8)	0.0454 (8)	0.0581 (9)	−0.0001 (6)	0.0219 (7)	−0.0071 (6)
N5	0.0443 (7)	0.0490 (8)	0.0459 (7)	0.0058 (6)	0.0151 (6)	−0.0025 (6)
O1	0.0705 (9)	0.0370 (7)	0.0891 (10)	0.0065 (6)	0.0204 (8)	0.0047 (6)
C1	0.0490 (9)	0.0383 (8)	0.0471 (8)	0.0063 (6)	0.0185 (7)	0.0056 (6)
C2	0.0391 (8)	0.0463 (9)	0.0504 (9)	0.0041 (6)	0.0201 (7)	0.0035 (7)
C3	0.0380 (7)	0.0432 (8)	0.0444 (8)	0.0131 (6)	0.0174 (6)	0.0026 (6)
C4	0.0393 (7)	0.0393 (8)	0.0399 (7)	0.0091 (6)	0.0183 (6)	0.0011 (6)
C5	0.0539 (10)	0.0363 (8)	0.0587 (10)	0.0045 (7)	0.0238 (8)	0.0010 (7)
C6	0.0470 (9)	0.0666 (12)	0.0486 (10)	0.0088 (8)	0.0112 (8)	0.0008 (8)
C7	0.0563 (11)	0.0512 (10)	0.0550 (10)	0.0203 (8)	0.0102 (8)	0.0034 (8)
C8A	0.090 (6)	0.097 (8)	0.091 (7)	0.052 (6)	0.044 (6)	0.017 (6)
C8B	0.089 (6)	0.075 (6)	0.123 (10)	0.046 (4)	0.076 (7)	0.039 (6)

Geometric parameters (Å, º) top

N1—C3	1.275 (2)	C3—C6	1.487 (2)
N1—N2	1.4018 (18)	C5—H5	0.9300
N2—C5	1.360 (2)	C6—H6A	0.9954
N2—C4	1.3651 (19)	C6—H6B	0.9488
N3—C1	1.368 (2)	C6—H6C	0.9724
N3—C4	1.3888 (19)	C7—C8A	1.381 (17)
N3—C7	1.485 (2)	C7—C8B	1.58 (2)
N4—C5	1.295 (2)	C7—H7A	0.9700
N4—N5	1.392 (2)	C7—H7B	0.9700
N5—C4	1.303 (2)	C8A—H8A1	0.9600
O1—C1	1.218 (2)	C8A—H8A2	0.9600
C1—C2	1.503 (2)	C8A—H8A3	0.9600
C2—C3	1.501 (2)	C8B—H8B1	0.9600
C2—H2A	0.9700	C8B—H8B2	0.9600
C2—H2B	0.9700	C8B—H8B3	0.9600

C3—N1—N2	115.11 (13)	N2—C5—H5	124.5
C5—N2—C4	104.34 (13)	C3—C6—H6A	105.8
C5—N2—N1	122.76 (13)	C3—C6—H6B	110.7
C4—N2—N1	131.62 (12)	H6A—C6—H6B	115.5
C1—N3—C4	123.12 (13)	C3—C6—H6C	110.0
C1—N3—C7	119.04 (14)	H6A—C6—H6C	103.1
C4—N3—C7	116.85 (13)	H6B—C6—H6C	111.4
C5—N4—N5	107.22 (13)	C8A—C7—N3	114.7 (8)
C4—N5—N4	106.80 (13)	N3—C7—C8B	109.6 (7)
O1—C1—N3	121.73 (16)	C8A—C7—H7A	108.6
O1—C1—C2	122.02 (15)	N3—C7—H7A	108.6
N3—C1—C2	116.25 (13)	C8A—C7—H7B	108.6
C3—C2—C1	111.53 (13)	N3—C7—H7B	108.6
C3—C2—H2A	109.3	H7A—C7—H7B	107.6
C1—C2—H2A	109.3	C7—C8A—H8A1	109.5
C3—C2—H2B	109.3	C7—C8A—H8A2	109.5
C1—C2—H2B	109.3	H8A1—C8A—H8A2	109.5
H2A—C2—H2B	108.0	C7—C8A—H8A3	109.5
N1—C3—C6	117.64 (15)	H8A1—C8A—H8A3	109.5
N1—C3—C2	123.54 (14)	H8A2—C8A—H8A3	109.5
C6—C3—C2	118.82 (14)	C7—C8B—H8B1	109.5
N5—C4—N2	110.65 (13)	C7—C8B—H8B2	109.5
N5—C4—N3	124.87 (14)	H8B1—C8B—H8B2	109.5
N2—C4—N3	124.40 (13)	C7—C8B—H8B3	109.5
N4—C5—N2	110.98 (15)	H8B1—C8B—H8B3	109.5
N4—C5—H5	124.5	H8B2—C8B—H8B3	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O1ⁱ	0.93	2.44	3.280 (2)	151

Symmetry code: (i) x, y+1, z.

Acknowledgements

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements and the Mohammed V University in Rabat, for financial support.

References

Basile, A. S., Gammal, S. M., Jones, E. A. & Skolnick, P. (1989). J. Neurochem. 53, 1057–1063. CrossRef CAS Google Scholar
Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Essassi, E. M., Lavergne, J. P. & Viallffont, P. (1977). Tetrahedron, 33, 2807–2812. CrossRef CAS Web of Science Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Gupta, M., Paul, S. & Gupta, R. (2011). Eur. J. Med. Chem. 46, 631–635. Web of Science CrossRef CAS PubMed Google Scholar
Harmaoui, A., Bouhfid, R., Essassi, E. M., Saadi, M. & El Ammari, L. (2015). Acta Cryst. E71, o1–o2. Web of Science CSD CrossRef IUCr Journals Google Scholar
Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Zemama, R. M., Amari, I., Bouhfid, R., Essassi, E. M. & Ng, S. W. (2009). Acta Cryst. E65, o2148. CSD CrossRef IUCr Journals Google Scholar
Zhao, C., Sham, H. L., Sun, M., Stoll, V. S., Stewart, K. D., Lin, S., Mo, H., Vasavanonda, S., Saldivar, A., Park, C., McDonald, E. J., Marsh, K. C., Klein, L. L., Kempf, D. J. & Norbeck, D. W. (2005). Bioorg. Med. Chem. Lett. 15, 5499–5503. CrossRef CAS Google Scholar

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IUCrDATA

ISSN: 2414-3146

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https://doi.org/10.1107/S2414314616018976

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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

9-Ethyl-6-methyl-7H-1,2,4-triazolo[4,3-b][1,2,4]triazepin-8(9H)-one

Structure description

Synthesis and crystallization

Refinement

Structural data

Acknowledgements

References

organic compounds