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

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).

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.002 Å
• Disorder in main residue
• R factor = 0.045
• wR factor = 0.133
• Data-to-parameter ratio = 15.4

checkCIF/PLATON results

No syntax errors found



Alert level G
PLAT154_ALERT_1_G The s.u.'s on the Cell Angles are Equal ..(Note)      0.002 Degree
PLAT301_ALERT_3_G Main Residue  Disorder ............ Percentage =          7 Note
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          6 Note
PLAT978_ALERT_2_G Number C-C Bonds with Positive Residual Density           3 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   0 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   4 ALERT level G = General information/check it is not something unexpected

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

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

Crystal data

C8H11N5O	Z = 2
Mr = 193.22	F(000) = 204
Triclinic, P1	Dx = 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) Å^3	0.37 × 0.32 × 0.27 mm

Data collection

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

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: mixed
wR(F^2) = 0.133	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0656P)^2 + 0.1549P] where P = (Fo^2 + 2Fc^2)/3
2105 reflections	(Δ/σ)max < 0.001
137 parameters	Δρmax = 0.32 e Å^−3
0 restraints	Δρmin = −0.17 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq	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 (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
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)

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)

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O1^i	0.93	2.44	3.280 (2)	151

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