5,6-Dimethyl­pyrazine-2,3-dicarbonitrile

Bardajee, G.R.; Lough, A.J.; Winnik, M.A.

doi:10.1107/S1600536812043474

organic compounds

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ISSN: 2056-9890

Volume 68| Part 11| November 2012| Page o3220

doi:10.1107/S1600536812043474

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5,6-Dimethylpyrazine-2,3-dicarbonitrile

Ghasem Rezanejade Bardajee,^a Alan J. Lough ^b ^* and Mitchell A. Winnik ^b

^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 ); 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

Crystal data

C₈H₆N₄
M_r = 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 ) T_min = 0.711, T_max = 0.746
7543 measured reflections
3650 independent reflections
2927 reflections with I > 2σ(I)
R_int = 0.034

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.110
S = 1.05
3650 reflections
222 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; 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).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812043474/hb6967sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812043474/hb6967Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812043474/hb6967Isup3.cml

checkCIF report

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.

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

Fig. 1. The asymmetric unit of the title compound.

5,6-Dimethylpyrazine-2,3-dicarbonitrile top

Crystal data top

C₈H₆N₄	F(000) = 1312
M_r = 158.17	D_x = 1.316 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 3553 reflections
a = 24.183 (2) Å	θ = 2.5–27.5°
b = 9.210 (1) Å	µ = 0.09 mm⁻¹
c = 18.761 (2) Å	T = 150 K
β = 130.151 (2)°	Block, colourless
V = 3193.8 (6) Å³	0.28 × 0.22 × 0.18 mm
Z = 16

Data collection top

Bruker Kappa APEXII DUO CCD diffractometer	3650 independent reflections
Radiation source: fine-focus sealed tube	2927 reflections with I > 2σ(I)
Bruker Triumph monochromator	R_int = 0.034
ϕ and ω scans	θ_max = 27.5°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −31→31
T_min = 0.711, T_max = 0.746	k = −11→11
7543 measured reflections	l = −23→24

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.110	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.057P)² + 0.5454P] where P = (F_o² + 2F_c²)/3
3650 reflections	(Δ/σ)_max = 0.001
222 parameters	Δρ_max = 0.21 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₈H₆N₄	V = 3193.8 (6) Å³
M_r = 158.17	Z = 16
Monoclinic, C2/c	Mo Kα radiation
a = 24.183 (2) Å	µ = 0.09 mm⁻¹
b = 9.210 (1) Å	T = 150 K
c = 18.761 (2) Å	0.28 × 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)
T_min = 0.711, T_max = 0.746	R_int = 0.034
7543 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	0 restraints
wR(F²) = 0.110	H-atom parameters constrained
S = 1.05	Δρ_max = 0.21 e Å⁻³
3650 reflections	Δρ_min = −0.21 e Å⁻³
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

	x	y	z	U_iso*/U_eq
N1A	0.04856 (10)	0.48725 (16)	0.69738 (13)	0.0248 (4)
N2A	0.19891 (9)	0.49247 (15)	0.79770 (12)	0.0243 (4)
N3A	0.02419 (9)	0.11627 (19)	0.68396 (15)	0.0406 (4)
N4A	0.23018 (9)	0.12325 (19)	0.81987 (14)	0.0376 (4)
C1A	0.08817 (10)	0.3648 (2)	0.72638 (13)	0.0236 (4)
C2A	0.16196 (10)	0.3674 (2)	0.77523 (12)	0.0227 (4)
C3A	0.08416 (11)	0.6117 (2)	0.71857 (12)	0.0249 (4)
C4A	0.16036 (11)	0.6147 (2)	0.76943 (14)	0.0245 (4)
C5A	0.05086 (12)	0.2266 (2)	0.70240 (16)	0.0275 (5)
C6A	0.20185 (12)	0.2326 (2)	0.80236 (17)	0.0269 (5)
C7A	0.04121 (14)	0.7493 (2)	0.68703 (18)	0.0338 (6)
H7AA	−0.0082	0.7271	0.6615	0.051*
H7AB	0.0398	0.7954	0.6388	0.051*
H7AC	0.0639	0.8155	0.7402	0.051*
C8A	0.19974 (14)	0.7552 (2)	0.79508 (18)	0.0312 (5)
H8AA	0.2503	0.7364	0.8246	0.047*
H8AB	0.1977	0.8079	0.8387	0.047*
H8AC	0.1771	0.8138	0.7388	0.047*
N1B	0.09889 (10)	0.74478 (15)	0.54586 (13)	0.0259 (4)
N2B	0.14892 (10)	0.73602 (17)	0.44671 (13)	0.0272 (4)
N3B	0.07877 (10)	0.3751 (2)	0.55725 (13)	0.0378 (4)
N4B	0.15302 (10)	0.36510 (18)	0.42592 (13)	0.0367 (4)
C1B	0.10706 (10)	0.6194 (2)	0.51766 (13)	0.0234 (4)
C2B	0.13235 (10)	0.6149 (2)	0.46911 (13)	0.0234 (4)
C3B	0.11532 (10)	0.8655 (2)	0.52460 (13)	0.0258 (4)
C4B	0.14069 (10)	0.8614 (2)	0.47436 (13)	0.0268 (4)
C5B	0.09057 (12)	0.4855 (2)	0.54051 (15)	0.0276 (5)
C6B	0.14345 (12)	0.4770 (3)	0.44367 (16)	0.0277 (5)
C7B	0.10652 (13)	1.0064 (3)	0.55575 (18)	0.0347 (6)
H7BA	0.0831	0.9892	0.5823	0.052*
H7BB	0.0766	1.0721	0.5023	0.052*
H7BC	0.1541	1.0504	0.6031	0.052*
C8B	0.15737 (15)	0.9966 (3)	0.44719 (19)	0.0385 (6)
H8BA	0.1780	0.9705	0.4180	0.058*
H8BB	0.1922	1.0555	0.5029	0.058*
H8BC	0.1128	1.0523	0.4029	0.058*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1A	0.0244 (9)	0.0262 (8)	0.0213 (8)	−0.0012 (6)	0.0135 (8)	−0.0013 (6)
N2A	0.0252 (9)	0.0241 (9)	0.0209 (8)	−0.0027 (6)	0.0136 (8)	−0.0024 (6)
N3A	0.0297 (9)	0.0301 (8)	0.0433 (9)	−0.0022 (7)	0.0150 (8)	0.0007 (8)
N4A	0.0269 (8)	0.0308 (8)	0.0386 (9)	0.0008 (7)	0.0135 (8)	−0.0011 (7)
C1A	0.0265 (9)	0.0230 (10)	0.0198 (8)	−0.0027 (8)	0.0142 (8)	−0.0011 (7)
C2A	0.0217 (9)	0.0237 (9)	0.0183 (8)	−0.0001 (7)	0.0109 (7)	−0.0010 (7)
C3A	0.0306 (10)	0.0235 (9)	0.0215 (9)	0.0014 (8)	0.0172 (8)	−0.0013 (7)
C4A	0.0289 (10)	0.0238 (9)	0.0232 (9)	−0.0033 (8)	0.0178 (8)	−0.0027 (7)
C5A	0.0205 (10)	0.0266 (11)	0.0260 (9)	−0.0008 (8)	0.0107 (8)	0.0018 (8)
C6A	0.0220 (10)	0.0256 (11)	0.0265 (10)	−0.0046 (8)	0.0127 (9)	−0.0022 (8)
C7A	0.0375 (13)	0.0221 (12)	0.0402 (13)	0.0047 (8)	0.0242 (12)	0.0000 (8)
C8A	0.0340 (12)	0.0226 (12)	0.0319 (11)	−0.0049 (8)	0.0190 (10)	−0.0034 (7)
N1B	0.0249 (9)	0.0257 (10)	0.0246 (10)	0.0005 (6)	0.0148 (8)	−0.0026 (6)
N2B	0.0265 (10)	0.0275 (9)	0.0250 (9)	−0.0025 (6)	0.0155 (9)	0.0003 (6)
N3B	0.0564 (12)	0.0305 (8)	0.0387 (9)	−0.0069 (8)	0.0362 (9)	−0.0043 (7)
N4B	0.0504 (11)	0.0293 (8)	0.0418 (9)	0.0023 (8)	0.0349 (9)	0.0005 (7)
C1B	0.0215 (9)	0.0252 (10)	0.0201 (8)	−0.0014 (7)	0.0119 (8)	−0.0008 (7)
C2B	0.0213 (9)	0.0246 (10)	0.0198 (8)	−0.0013 (7)	0.0113 (8)	−0.0008 (7)
C3B	0.0187 (9)	0.0250 (10)	0.0226 (9)	−0.0008 (7)	0.0083 (8)	−0.0009 (7)
C4B	0.0216 (9)	0.0274 (10)	0.0231 (9)	−0.0002 (8)	0.0106 (8)	0.0010 (8)
C5B	0.0333 (11)	0.0283 (12)	0.0242 (10)	−0.0009 (8)	0.0198 (9)	−0.0025 (8)
C6B	0.0294 (11)	0.0323 (12)	0.0247 (10)	−0.0021 (9)	0.0190 (9)	0.0015 (8)
C7B	0.0325 (12)	0.0301 (12)	0.0384 (12)	0.0015 (9)	0.0215 (11)	−0.0023 (9)
C8B	0.0439 (14)	0.0301 (13)	0.0432 (14)	−0.0044 (9)	0.0288 (12)	0.0023 (9)

Geometric parameters (Å, º) top

N1A—C3A	1.331 (2)	N1B—C3B	1.326 (3)
N1A—C1A	1.346 (3)	N1B—C1B	1.337 (3)
N2A—C4A	1.334 (2)	N2B—C4B	1.333 (3)
N2A—C2A	1.348 (2)	N2B—C2B	1.341 (3)
N3A—C5A	1.132 (3)	N3B—C5B	1.153 (3)
N4A—C6A	1.141 (3)	N4B—C6B	1.151 (3)
C1A—C2A	1.384 (3)	C1B—C2B	1.387 (3)
C1A—C5A	1.454 (3)	C1B—C5B	1.444 (3)
C2A—C6A	1.448 (3)	C2B—C6B	1.442 (3)
C3A—C4A	1.428 (3)	C3B—C4B	1.418 (3)
C3A—C7A	1.497 (3)	C3B—C7B	1.494 (3)
C4A—C8A	1.491 (3)	C4B—C8B	1.496 (3)
C7A—H7AA	0.9800	C7B—H7BA	0.9800
C7A—H7AB	0.9800	C7B—H7BB	0.9800
C7A—H7AC	0.9800	C7B—H7BC	0.9800
C8A—H8AA	0.9800	C8B—H8BA	0.9800
C8A—H8AB	0.9800	C8B—H8BB	0.9800
C8A—H8AC	0.9800	C8B—H8BC	0.9800

C3A—N1A—C1A	116.49 (17)	C3B—N1B—C1B	117.12 (19)
C4A—N2A—C2A	116.36 (17)	C4B—N2B—C2B	116.69 (19)
N1A—C1A—C2A	122.05 (17)	N1B—C1B—C2B	121.73 (17)
N1A—C1A—C5A	118.06 (17)	N1B—C1B—C5B	118.72 (18)
C2A—C1A—C5A	119.86 (17)	C2B—C1B—C5B	119.53 (17)
N2A—C2A—C1A	122.25 (17)	N2B—C2B—C1B	121.89 (17)
N2A—C2A—C6A	117.74 (17)	N2B—C2B—C6B	118.18 (18)
C1A—C2A—C6A	120.00 (17)	C1B—C2B—C6B	119.91 (17)
N1A—C3A—C4A	121.55 (17)	N1B—C3B—C4B	121.32 (17)
N1A—C3A—C7A	117.42 (18)	N1B—C3B—C7B	117.71 (19)
C4A—C3A—C7A	121.03 (18)	C4B—C3B—C7B	120.97 (19)
N2A—C4A—C3A	121.30 (16)	N2B—C4B—C3B	121.25 (18)
N2A—C4A—C8A	117.84 (18)	N2B—C4B—C8B	116.6 (2)
C3A—C4A—C8A	120.83 (17)	C3B—C4B—C8B	122.12 (18)
N3A—C5A—C1A	176.9 (2)	N3B—C5B—C1B	176.8 (2)
N4A—C6A—C2A	176.6 (3)	N4B—C6B—C2B	177.9 (2)
C3A—C7A—H7AA	109.5	C3B—C7B—H7BA	109.5
C3A—C7A—H7AB	109.5	C3B—C7B—H7BB	109.5
H7AA—C7A—H7AB	109.5	H7BA—C7B—H7BB	109.5
C3A—C7A—H7AC	109.5	C3B—C7B—H7BC	109.5
H7AA—C7A—H7AC	109.5	H7BA—C7B—H7BC	109.5
H7AB—C7A—H7AC	109.5	H7BB—C7B—H7BC	109.5
C4A—C8A—H8AA	109.5	C4B—C8B—H8BA	109.5
C4A—C8A—H8AB	109.5	C4B—C8B—H8BB	109.5
H8AA—C8A—H8AB	109.5	H8BA—C8B—H8BB	109.5
C4A—C8A—H8AC	109.5	C4B—C8B—H8BC	109.5
H8AA—C8A—H8AC	109.5	H8BA—C8B—H8BC	109.5
H8AB—C8A—H8AC	109.5	H8BB—C8B—H8BC	109.5

C3A—N1A—C1A—C2A	−0.4 (3)	C3B—N1B—C1B—C2B	0.7 (3)
C3A—N1A—C1A—C5A	−178.40 (18)	C3B—N1B—C1B—C5B	179.24 (18)
C4A—N2A—C2A—C1A	−0.7 (3)	C4B—N2B—C2B—C1B	0.7 (3)
C4A—N2A—C2A—C6A	178.1 (2)	C4B—N2B—C2B—C6B	−177.5 (2)
N1A—C1A—C2A—N2A	0.7 (3)	N1B—C1B—C2B—N2B	−1.0 (3)
C5A—C1A—C2A—N2A	178.75 (17)	C5B—C1B—C2B—N2B	−179.54 (17)
N1A—C1A—C2A—C6A	−178.02 (17)	N1B—C1B—C2B—C6B	177.20 (19)
C5A—C1A—C2A—C6A	0.0 (3)	C5B—C1B—C2B—C6B	−1.3 (3)
C1A—N1A—C3A—C4A	0.0 (3)	C1B—N1B—C3B—C4B	−0.2 (3)
C1A—N1A—C3A—C7A	−179.98 (19)	C1B—N1B—C3B—C7B	−179.94 (19)
C2A—N2A—C4A—C3A	0.3 (3)	C2B—N2B—C4B—C3B	−0.3 (3)
C2A—N2A—C4A—C8A	178.52 (19)	C2B—N2B—C4B—C8B	−178.47 (19)
N1A—C3A—C4A—N2A	0.0 (3)	N1B—C3B—C4B—N2B	0.0 (3)
C7A—C3A—C4A—N2A	−179.99 (18)	C7B—C3B—C4B—N2B	179.73 (19)
N1A—C3A—C4A—C8A	−178.13 (18)	N1B—C3B—C4B—C8B	178.10 (19)
C7A—C3A—C4A—C8A	1.8 (3)	C7B—C3B—C4B—C8B	−2.2 (3)

Experimental details

Crystal data
Chemical formula	C₈H₆N₄
M_r	158.17
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	150
a, b, c (Å)	24.183 (2), 9.210 (1), 18.761 (2)
β (°)	130.151 (2)
V (Å³)	3193.8 (6)
Z	16
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.28 × 0.22 × 0.18

Data collection
Diffractometer	Bruker Kappa APEXII DUO CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2007)
T_min, T_max	0.711, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	7543, 3650, 2927
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.110, 1.05
No. of reflections	3650
No. of parameters	222
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	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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