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ISSN: 2056-9890

5,6-Di­methyl­pyrazine-2,3-dicarbo­nitrile

aDepartment of Chemistry, Payame Noor University, PO Box 19395-3697, Tehran, Iran, and bDepartment of Chemistry, University of Toronto, 80 St Geroge St, Toronto, Ontario, Canada M5S 3H6
*Correspondence e-mail: alough@chem.utoronto.ca

(Received 4 October 2012; accepted 19 October 2012; online 27 October 2012)

The asymmetric unit of the title compound, C8H6N4, contains two almost planar independent mol­ecules (r.m.s. deviations = 0.026 and 0.030 Å). The crystal studied was a non-merohedral twin with the components in a 0.513 (2):0.487 (2) ratio.

Related literature

For applications of pyrazine compounds and their derivatives, see: He et al. (2003[He, W., Meyers, M. R., Hanney, B., Sapada, A., Blider, g., Galzeinski, H., Amin, D., Needle, S. Page, K., Jayyosi, Z. & Perrone, H. (2003). Bioorg. Med. Chem. Lett. 13, 3097-3100.]); Yadav et al. (2008[Yadav, J. S., Reddy, B. V. S., Premalatha, K. & Shankar, K. S. (2008). Synthesis, pp. 3787-3792.]). For the synthesis, see: Bardajee et al. (2012[Bardajee, G. R., Malakooti, R., Jamia, F., Parsaei, Z. & Atashin, H. (2012). Catal. Commun. 27, 49-53.]). For related structures, see: Hökelek et al. (2009[Hökelek, T., Yalçın, E., Seferoğlu, Z. & Şahin, E. (2009). Acta Cryst. E65, o2225.]); Donzello et al. (2004[Donzello, M. P., Ou, Z., Monacelli, F., Ricciardi, G., Rizzoli, C., Ercolani, C. & Kadish, K. H. (2004). Inorg. Chem. 43, 8626-8636.]); Cristiano et al. (2007[Cristiano, R., Westphal, E., Bechtold, I. H., Bortoluzzi, A. J. & Gallardo, H. (2007). Tetrahedron, 63, 2851-2858.]).

[Scheme 1]

Experimental

Crystal data
  • C8H6N4

  • Mr = 158.17

  • Monoclinic, C 2/c

  • a = 24.183 (2) Å

  • b = 9.210 (1) Å

  • c = 18.761 (2) Å

  • β = 130.151 (2)°

  • V = 3193.8 (6) Å3

  • Z = 16

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 150 K

  • 0.28 × 0.22 × 0.18 mm

Data collection
  • Bruker Kappa APEXII DUO CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2007[Bruker (2007). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.711, Tmax = 0.746

  • 7543 measured reflections

  • 3650 independent reflections

  • 2927 reflections with I > 2σ(I)

  • Rint = 0.034

Refinement
  • R[F2 > 2σ(F2)] = 0.039

  • wR(F2) = 0.110

  • S = 1.05

  • 3650 reflections

  • 222 parameters

  • H-atom parameters constrained

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.21 e Å−3

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Supporting information


Comment top

Pyrazine is a nitrogen containing heterocycle and is a major scaffold for other heterocycles such as pyridopyrazines and quinoxalines. These compounds have received considerable attention in the pharmaceutical industry because of their interesting therapeutic properties (He et al., 2003; Yadav et al., 2008). Herein, we report the crystal structure of the title compound (I).

The asymmetric unit of (I) contains two independent molecules (A and B) (Fig. 1). In (I) the bond distances are similar to the equivalent distances in 5,6-diphenylpyrazine-2,3-dicarbonitrile (Hökelek et al., 2009), 5,6-bis(2-pyridyl)-2,3-pyrazinedicarbonitrile (Donzello et al., 2004) and 5,6-bis(4-methoxyphenyl)-2,3-pyrazinedicarbonitrile (Cristiano et al., 2007).

Related literature top

For applications of pyrazine compounds and their derivatives, see: He et al. (2003); Yadav et al. (2008). For the synthesis, see: Bardajee et al. (2012). For related structures, see: Hökelek et al. (2009); Donzello et al. (2004); Cristiano et al. (2007).

Experimental top

The title compound was synthesized from the reaction of 2,3-diaminomaleonitrile and biacetyl in the presence a heterogeneous catalyst based on copper bearing salen Schiff base ligands covalently anchored into SBA-15 in water (Bardajee et al. 2012). Colourless blocks were grown from a solution of the title compound in ethanol.

Refinement top

Hydrogen atoms were placed in calculated positions with C—H distances of 0.98 Å and were included in the refinement in a riding-model approximation with Uiso(H) = 1.5Ueq(C). The crystal studied was a non-merohedral twin with twin law -1 0 0, 0 - 1 0, 1 0 1 and with the components in a ratio of 0.513 (2):0.487 (2).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The asymmetric unit of the title compound.
5,6-Dimethylpyrazine-2,3-dicarbonitrile top
Crystal data top
C8H6N4F(000) = 1312
Mr = 158.17Dx = 1.316 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 3553 reflections
a = 24.183 (2) Åθ = 2.5–27.5°
b = 9.210 (1) ŵ = 0.09 mm1
c = 18.761 (2) ÅT = 150 K
β = 130.151 (2)°Block, colourless
V = 3193.8 (6) Å30.28 × 0.22 × 0.18 mm
Z = 16
Data collection top
Bruker Kappa APEXII DUO CCD
diffractometer
3650 independent reflections
Radiation source: fine-focus sealed tube2927 reflections with I > 2σ(I)
Bruker Triumph monochromatorRint = 0.034
ϕ and ω scansθmax = 27.5°, θmin = 2.2°
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
h = 3131
Tmin = 0.711, Tmax = 0.746k = 1111
7543 measured reflectionsl = 2324
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)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.110H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.057P)2 + 0.5454P]
where P = (Fo2 + 2Fc2)/3
3650 reflections(Δ/σ)max = 0.001
222 parametersΔρmax = 0.21 e Å3
0 restraintsΔρmin = 0.21 e Å3
Crystal data top
C8H6N4V = 3193.8 (6) Å3
Mr = 158.17Z = 16
Monoclinic, C2/cMo Kα radiation
a = 24.183 (2) ŵ = 0.09 mm1
b = 9.210 (1) ÅT = 150 K
c = 18.761 (2) Å0.28 × 0.22 × 0.18 mm
β = 130.151 (2)°
Data collection top
Bruker Kappa APEXII DUO CCD
diffractometer
3650 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
2927 reflections with I > 2σ(I)
Tmin = 0.711, Tmax = 0.746Rint = 0.034
7543 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.110H-atom parameters constrained
S = 1.05Δρmax = 0.21 e Å3
3650 reflectionsΔρmin = 0.21 e Å3
222 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
N1A0.04856 (10)0.48725 (16)0.69738 (13)0.0248 (4)
N2A0.19891 (9)0.49247 (15)0.79770 (12)0.0243 (4)
N3A0.02419 (9)0.11627 (19)0.68396 (15)0.0406 (4)
N4A0.23018 (9)0.12325 (19)0.81987 (14)0.0376 (4)
C1A0.08817 (10)0.3648 (2)0.72638 (13)0.0236 (4)
C2A0.16196 (10)0.3674 (2)0.77523 (12)0.0227 (4)
C3A0.08416 (11)0.6117 (2)0.71857 (12)0.0249 (4)
C4A0.16036 (11)0.6147 (2)0.76943 (14)0.0245 (4)
C5A0.05086 (12)0.2266 (2)0.70240 (16)0.0275 (5)
C6A0.20185 (12)0.2326 (2)0.80236 (17)0.0269 (5)
C7A0.04121 (14)0.7493 (2)0.68703 (18)0.0338 (6)
H7AA0.00820.72710.66150.051*
H7AB0.03980.79540.63880.051*
H7AC0.06390.81550.74020.051*
C8A0.19974 (14)0.7552 (2)0.79508 (18)0.0312 (5)
H8AA0.25030.73640.82460.047*
H8AB0.19770.80790.83870.047*
H8AC0.17710.81380.73880.047*
N1B0.09889 (10)0.74478 (15)0.54586 (13)0.0259 (4)
N2B0.14892 (10)0.73602 (17)0.44671 (13)0.0272 (4)
N3B0.07877 (10)0.3751 (2)0.55725 (13)0.0378 (4)
N4B0.15302 (10)0.36510 (18)0.42592 (13)0.0367 (4)
C1B0.10706 (10)0.6194 (2)0.51766 (13)0.0234 (4)
C2B0.13235 (10)0.6149 (2)0.46911 (13)0.0234 (4)
C3B0.11532 (10)0.8655 (2)0.52460 (13)0.0258 (4)
C4B0.14069 (10)0.8614 (2)0.47436 (13)0.0268 (4)
C5B0.09057 (12)0.4855 (2)0.54051 (15)0.0276 (5)
C6B0.14345 (12)0.4770 (3)0.44367 (16)0.0277 (5)
C7B0.10652 (13)1.0064 (3)0.55575 (18)0.0347 (6)
H7BA0.08310.98920.58230.052*
H7BB0.07661.07210.50230.052*
H7BC0.15411.05040.60310.052*
C8B0.15737 (15)0.9966 (3)0.44719 (19)0.0385 (6)
H8BA0.17800.97050.41800.058*
H8BB0.19221.05550.50290.058*
H8BC0.11281.05230.40290.058*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N1A0.0244 (9)0.0262 (8)0.0213 (8)0.0012 (6)0.0135 (8)0.0013 (6)
N2A0.0252 (9)0.0241 (9)0.0209 (8)0.0027 (6)0.0136 (8)0.0024 (6)
N3A0.0297 (9)0.0301 (8)0.0433 (9)0.0022 (7)0.0150 (8)0.0007 (8)
N4A0.0269 (8)0.0308 (8)0.0386 (9)0.0008 (7)0.0135 (8)0.0011 (7)
C1A0.0265 (9)0.0230 (10)0.0198 (8)0.0027 (8)0.0142 (8)0.0011 (7)
C2A0.0217 (9)0.0237 (9)0.0183 (8)0.0001 (7)0.0109 (7)0.0010 (7)
C3A0.0306 (10)0.0235 (9)0.0215 (9)0.0014 (8)0.0172 (8)0.0013 (7)
C4A0.0289 (10)0.0238 (9)0.0232 (9)0.0033 (8)0.0178 (8)0.0027 (7)
C5A0.0205 (10)0.0266 (11)0.0260 (9)0.0008 (8)0.0107 (8)0.0018 (8)
C6A0.0220 (10)0.0256 (11)0.0265 (10)0.0046 (8)0.0127 (9)0.0022 (8)
C7A0.0375 (13)0.0221 (12)0.0402 (13)0.0047 (8)0.0242 (12)0.0000 (8)
C8A0.0340 (12)0.0226 (12)0.0319 (11)0.0049 (8)0.0190 (10)0.0034 (7)
N1B0.0249 (9)0.0257 (10)0.0246 (10)0.0005 (6)0.0148 (8)0.0026 (6)
N2B0.0265 (10)0.0275 (9)0.0250 (9)0.0025 (6)0.0155 (9)0.0003 (6)
N3B0.0564 (12)0.0305 (8)0.0387 (9)0.0069 (8)0.0362 (9)0.0043 (7)
N4B0.0504 (11)0.0293 (8)0.0418 (9)0.0023 (8)0.0349 (9)0.0005 (7)
C1B0.0215 (9)0.0252 (10)0.0201 (8)0.0014 (7)0.0119 (8)0.0008 (7)
C2B0.0213 (9)0.0246 (10)0.0198 (8)0.0013 (7)0.0113 (8)0.0008 (7)
C3B0.0187 (9)0.0250 (10)0.0226 (9)0.0008 (7)0.0083 (8)0.0009 (7)
C4B0.0216 (9)0.0274 (10)0.0231 (9)0.0002 (8)0.0106 (8)0.0010 (8)
C5B0.0333 (11)0.0283 (12)0.0242 (10)0.0009 (8)0.0198 (9)0.0025 (8)
C6B0.0294 (11)0.0323 (12)0.0247 (10)0.0021 (9)0.0190 (9)0.0015 (8)
C7B0.0325 (12)0.0301 (12)0.0384 (12)0.0015 (9)0.0215 (11)0.0023 (9)
C8B0.0439 (14)0.0301 (13)0.0432 (14)0.0044 (9)0.0288 (12)0.0023 (9)
Geometric parameters (Å, º) top
N1A—C3A1.331 (2)N1B—C3B1.326 (3)
N1A—C1A1.346 (3)N1B—C1B1.337 (3)
N2A—C4A1.334 (2)N2B—C4B1.333 (3)
N2A—C2A1.348 (2)N2B—C2B1.341 (3)
N3A—C5A1.132 (3)N3B—C5B1.153 (3)
N4A—C6A1.141 (3)N4B—C6B1.151 (3)
C1A—C2A1.384 (3)C1B—C2B1.387 (3)
C1A—C5A1.454 (3)C1B—C5B1.444 (3)
C2A—C6A1.448 (3)C2B—C6B1.442 (3)
C3A—C4A1.428 (3)C3B—C4B1.418 (3)
C3A—C7A1.497 (3)C3B—C7B1.494 (3)
C4A—C8A1.491 (3)C4B—C8B1.496 (3)
C7A—H7AA0.9800C7B—H7BA0.9800
C7A—H7AB0.9800C7B—H7BB0.9800
C7A—H7AC0.9800C7B—H7BC0.9800
C8A—H8AA0.9800C8B—H8BA0.9800
C8A—H8AB0.9800C8B—H8BB0.9800
C8A—H8AC0.9800C8B—H8BC0.9800
C3A—N1A—C1A116.49 (17)C3B—N1B—C1B117.12 (19)
C4A—N2A—C2A116.36 (17)C4B—N2B—C2B116.69 (19)
N1A—C1A—C2A122.05 (17)N1B—C1B—C2B121.73 (17)
N1A—C1A—C5A118.06 (17)N1B—C1B—C5B118.72 (18)
C2A—C1A—C5A119.86 (17)C2B—C1B—C5B119.53 (17)
N2A—C2A—C1A122.25 (17)N2B—C2B—C1B121.89 (17)
N2A—C2A—C6A117.74 (17)N2B—C2B—C6B118.18 (18)
C1A—C2A—C6A120.00 (17)C1B—C2B—C6B119.91 (17)
N1A—C3A—C4A121.55 (17)N1B—C3B—C4B121.32 (17)
N1A—C3A—C7A117.42 (18)N1B—C3B—C7B117.71 (19)
C4A—C3A—C7A121.03 (18)C4B—C3B—C7B120.97 (19)
N2A—C4A—C3A121.30 (16)N2B—C4B—C3B121.25 (18)
N2A—C4A—C8A117.84 (18)N2B—C4B—C8B116.6 (2)
C3A—C4A—C8A120.83 (17)C3B—C4B—C8B122.12 (18)
N3A—C5A—C1A176.9 (2)N3B—C5B—C1B176.8 (2)
N4A—C6A—C2A176.6 (3)N4B—C6B—C2B177.9 (2)
C3A—C7A—H7AA109.5C3B—C7B—H7BA109.5
C3A—C7A—H7AB109.5C3B—C7B—H7BB109.5
H7AA—C7A—H7AB109.5H7BA—C7B—H7BB109.5
C3A—C7A—H7AC109.5C3B—C7B—H7BC109.5
H7AA—C7A—H7AC109.5H7BA—C7B—H7BC109.5
H7AB—C7A—H7AC109.5H7BB—C7B—H7BC109.5
C4A—C8A—H8AA109.5C4B—C8B—H8BA109.5
C4A—C8A—H8AB109.5C4B—C8B—H8BB109.5
H8AA—C8A—H8AB109.5H8BA—C8B—H8BB109.5
C4A—C8A—H8AC109.5C4B—C8B—H8BC109.5
H8AA—C8A—H8AC109.5H8BA—C8B—H8BC109.5
H8AB—C8A—H8AC109.5H8BB—C8B—H8BC109.5
C3A—N1A—C1A—C2A0.4 (3)C3B—N1B—C1B—C2B0.7 (3)
C3A—N1A—C1A—C5A178.40 (18)C3B—N1B—C1B—C5B179.24 (18)
C4A—N2A—C2A—C1A0.7 (3)C4B—N2B—C2B—C1B0.7 (3)
C4A—N2A—C2A—C6A178.1 (2)C4B—N2B—C2B—C6B177.5 (2)
N1A—C1A—C2A—N2A0.7 (3)N1B—C1B—C2B—N2B1.0 (3)
C5A—C1A—C2A—N2A178.75 (17)C5B—C1B—C2B—N2B179.54 (17)
N1A—C1A—C2A—C6A178.02 (17)N1B—C1B—C2B—C6B177.20 (19)
C5A—C1A—C2A—C6A0.0 (3)C5B—C1B—C2B—C6B1.3 (3)
C1A—N1A—C3A—C4A0.0 (3)C1B—N1B—C3B—C4B0.2 (3)
C1A—N1A—C3A—C7A179.98 (19)C1B—N1B—C3B—C7B179.94 (19)
C2A—N2A—C4A—C3A0.3 (3)C2B—N2B—C4B—C3B0.3 (3)
C2A—N2A—C4A—C8A178.52 (19)C2B—N2B—C4B—C8B178.47 (19)
N1A—C3A—C4A—N2A0.0 (3)N1B—C3B—C4B—N2B0.0 (3)
C7A—C3A—C4A—N2A179.99 (18)C7B—C3B—C4B—N2B179.73 (19)
N1A—C3A—C4A—C8A178.13 (18)N1B—C3B—C4B—C8B178.10 (19)
C7A—C3A—C4A—C8A1.8 (3)C7B—C3B—C4B—C8B2.2 (3)

Experimental details

Crystal data
Chemical formulaC8H6N4
Mr158.17
Crystal system, space groupMonoclinic, C2/c
Temperature (K)150
a, b, c (Å)24.183 (2), 9.210 (1), 18.761 (2)
β (°) 130.151 (2)
V3)3193.8 (6)
Z16
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.28 × 0.22 × 0.18
Data collection
DiffractometerBruker Kappa APEXII DUO CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2007)
Tmin, Tmax0.711, 0.746
No. of measured, independent and
observed [I > 2σ(I)] reflections
7543, 3650, 2927
Rint0.034
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.110, 1.05
No. of reflections3650
No. of parameters222
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.21, 0.21

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

GRB is thankful to PNU for funding of this study and the University of Toronto thanks NSERC Canada for funding.

References

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