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

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

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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 ππ 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).

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

1,2,4-Triazepine derivatives are useful in the treatment of HIV infections (Zhao et al., 2005[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.]). It has been shown that heterocycles attached to a seven-membered ring possess important biological properties (Basile et al., 1989[Basile, A. S., Gammal, S. M., Jones, E. A. & Skolnick, P. (1989). J. Neurochem. 53, 1057-1063.]; Gupta et al., 2011[Gupta, M., Paul, S. & Gupta, R. (2011). Eur. J. Med. Chem. 46, 631-635.]). In a continuation of our studies on 1,2,4-triazolo[1,2,4]triazepine derivatives (Essassi et al., 1977[Essassi, E. M., Lavergne, J. P. & Viallffont, P. (1977). Tetrahedron, 33, 2807-2812.]; Harmaoui et al., 2015[Harmaoui, A., Bouhfid, R., Essassi, E. M., Saadi, M. & El Ammari, L. (2015). Acta Cryst. E71, o1-o2.]; Zemama et al., 2009[Zemama, R. M., Amari, I., Bouhfid, R., Essassi, E. M. & Ng, S. W. (2009). Acta Cryst. E65, o2148.]), we report herein on the synthesis and crystal structure of the title compound.

The mol­ecule of the title compound, Fig. 1[link], 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 QT = 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]
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[link] and Fig. 2[link]). Inversion-related chains are linked by offset ππ inter­actions between triazole rings [CgCgii = 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[link]).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C5—H5⋯O1i 0.93 2.44 3.280 (2) 151
Symmetry code: (i) x, y+1, z.
[Figure 2]
Figure 2
Crystal packing for the title compound, viewed normal to (101). The C—H⋯O hydrogen bonds (see Table 1[link]) and ππ 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[link]. 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
Mr 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)
V3) 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[Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3-10.])
Tmin, Tmax 0.595, 0.747
No. of measured, independent and observed [I > 2σ(I)] reflections 14339, 2105, 1746
Rint 0.027
(sin θ/λ)max−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
Δρmax, Δρmin (e Å−3) 0.32, −0.17
Computer programs: APEX2 and SAINT (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT2014 (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL2014 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]), ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]), Mercury (Macrae et al., 2008[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.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Structural data


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
C8H11N5OZ = 2
Mr = 193.22F(000) = 204
Triclinic, P1Dx = 1.351 Mg m3
a = 7.8989 (3) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.0880 (3) ÅCell parameters from 2105 reflections
c = 8.2052 (3) Åθ = 2.6–27.1°
α = 90.297 (2)°µ = 0.10 mm1
β = 113.319 (2)°T = 296 K
γ = 98.488 (2)°Block, colourless
V = 474.94 (3) Å30.37 × 0.32 × 0.27 mm
Data collection top
Bruker X8 APEX
diffractometer
2105 independent reflections
Radiation source: fine-focus sealed tube1746 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.027
φ and ω scansθmax = 27.1°, θmin = 2.6°
Absorption correction: multi-scan
(SADABS; Krause et al., 2015)
h = 1010
Tmin = 0.595, Tmax = 0.747k = 1010
14339 measured reflectionsl = 1010
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.045Hydrogen site location: mixed
wR(F2) = 0.133H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0656P)2 + 0.1549P]
where P = (Fo2 + 2Fc2)/3
2105 reflections(Δ/σ)max < 0.001
137 parametersΔρmax = 0.32 e Å3
0 restraintsΔρmin = 0.17 e Å3
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
xyzUiso*/UeqOcc. (<1)
N10.29573 (18)0.49763 (16)0.51599 (17)0.0436 (3)
N20.43326 (18)0.52817 (15)0.68976 (17)0.0391 (3)
N30.50084 (18)0.25055 (16)0.78018 (17)0.0432 (3)
N40.6626 (2)0.67889 (18)0.9111 (2)0.0534 (4)
N50.67342 (19)0.51047 (17)0.93918 (18)0.0476 (3)
O10.2994 (2)0.00760 (15)0.6764 (2)0.0695 (4)
C10.3253 (2)0.15975 (19)0.6984 (2)0.0451 (4)
C20.1666 (2)0.2584 (2)0.6363 (2)0.0449 (4)
H2A0.04890.18180.59310.054*
H2B0.17280.32790.73580.054*
C30.1734 (2)0.36744 (19)0.4908 (2)0.0409 (3)
C40.5351 (2)0.42416 (18)0.80585 (19)0.0384 (3)
C50.5207 (2)0.6849 (2)0.7627 (2)0.0496 (4)
H50.48360.78330.71280.059*
C60.0294 (2)0.3234 (2)0.3070 (2)0.0566 (5)
H6A0.03780.20650.27640.085*
H6B0.04580.40390.22860.085*
H6C0.09490.31300.30690.085*
C70.6598 (3)0.1615 (2)0.8760 (3)0.0567 (5)
H7A0.72230.20940.99770.068*
H7B0.61070.04500.87960.068*
C8A0.790 (3)0.168 (3)0.802 (3)0.086 (3)0.48 (6)
H8A10.88760.10770.87170.129*0.48 (6)
H8A20.73080.11780.68270.129*0.48 (6)
H8A30.84250.28250.80100.129*0.48 (6)
C8B0.759 (3)0.126 (3)0.750 (4)0.081 (4)0.52 (6)
H8B10.86180.06800.81190.122*0.52 (6)
H8B20.67130.05720.64640.122*0.52 (6)
H8B30.80470.22970.71380.122*0.52 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0447 (7)0.0447 (7)0.0404 (7)0.0115 (6)0.0146 (6)0.0063 (5)
N20.0414 (7)0.0349 (6)0.0414 (7)0.0077 (5)0.0165 (5)0.0026 (5)
N30.0437 (7)0.0382 (7)0.0468 (7)0.0130 (5)0.0150 (6)0.0029 (5)
N40.0534 (8)0.0454 (8)0.0581 (9)0.0001 (6)0.0219 (7)0.0071 (6)
N50.0443 (7)0.0490 (8)0.0459 (7)0.0058 (6)0.0151 (6)0.0025 (6)
O10.0705 (9)0.0370 (7)0.0891 (10)0.0065 (6)0.0204 (8)0.0047 (6)
C10.0490 (9)0.0383 (8)0.0471 (8)0.0063 (6)0.0185 (7)0.0056 (6)
C20.0391 (8)0.0463 (9)0.0504 (9)0.0041 (6)0.0201 (7)0.0035 (7)
C30.0380 (7)0.0432 (8)0.0444 (8)0.0131 (6)0.0174 (6)0.0026 (6)
C40.0393 (7)0.0393 (8)0.0399 (7)0.0091 (6)0.0183 (6)0.0011 (6)
C50.0539 (10)0.0363 (8)0.0587 (10)0.0045 (7)0.0238 (8)0.0010 (7)
C60.0470 (9)0.0666 (12)0.0486 (10)0.0088 (8)0.0112 (8)0.0008 (8)
C70.0563 (11)0.0512 (10)0.0550 (10)0.0203 (8)0.0102 (8)0.0034 (8)
C8A0.090 (6)0.097 (8)0.091 (7)0.052 (6)0.044 (6)0.017 (6)
C8B0.089 (6)0.075 (6)0.123 (10)0.046 (4)0.076 (7)0.039 (6)
Geometric parameters (Å, º) top
N1—C31.275 (2)C3—C61.487 (2)
N1—N21.4018 (18)C5—H50.9300
N2—C51.360 (2)C6—H6A0.9954
N2—C41.3651 (19)C6—H6B0.9488
N3—C11.368 (2)C6—H6C0.9724
N3—C41.3888 (19)C7—C8A1.381 (17)
N3—C71.485 (2)C7—C8B1.58 (2)
N4—C51.295 (2)C7—H7A0.9700
N4—N51.392 (2)C7—H7B0.9700
N5—C41.303 (2)C8A—H8A10.9600
O1—C11.218 (2)C8A—H8A20.9600
C1—C21.503 (2)C8A—H8A30.9600
C2—C31.501 (2)C8B—H8B10.9600
C2—H2A0.9700C8B—H8B20.9600
C2—H2B0.9700C8B—H8B30.9600
C3—N1—N2115.11 (13)N2—C5—H5124.5
C5—N2—C4104.34 (13)C3—C6—H6A105.8
C5—N2—N1122.76 (13)C3—C6—H6B110.7
C4—N2—N1131.62 (12)H6A—C6—H6B115.5
C1—N3—C4123.12 (13)C3—C6—H6C110.0
C1—N3—C7119.04 (14)H6A—C6—H6C103.1
C4—N3—C7116.85 (13)H6B—C6—H6C111.4
C5—N4—N5107.22 (13)C8A—C7—N3114.7 (8)
C4—N5—N4106.80 (13)N3—C7—C8B109.6 (7)
O1—C1—N3121.73 (16)C8A—C7—H7A108.6
O1—C1—C2122.02 (15)N3—C7—H7A108.6
N3—C1—C2116.25 (13)C8A—C7—H7B108.6
C3—C2—C1111.53 (13)N3—C7—H7B108.6
C3—C2—H2A109.3H7A—C7—H7B107.6
C1—C2—H2A109.3C7—C8A—H8A1109.5
C3—C2—H2B109.3C7—C8A—H8A2109.5
C1—C2—H2B109.3H8A1—C8A—H8A2109.5
H2A—C2—H2B108.0C7—C8A—H8A3109.5
N1—C3—C6117.64 (15)H8A1—C8A—H8A3109.5
N1—C3—C2123.54 (14)H8A2—C8A—H8A3109.5
C6—C3—C2118.82 (14)C7—C8B—H8B1109.5
N5—C4—N2110.65 (13)C7—C8B—H8B2109.5
N5—C4—N3124.87 (14)H8B1—C8B—H8B2109.5
N2—C4—N3124.40 (13)C7—C8B—H8B3109.5
N4—C5—N2110.98 (15)H8B1—C8B—H8B3109.5
N4—C5—H5124.5H8B2—C8B—H8B3109.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C5—H5···O1i0.932.443.280 (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

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