5-Methyl­pyrazine-2-carboxamide

Rillema, D.P.; Senaratne, N.K.; Moore, C.; KomReddy, V.

doi:10.1107/S2414314617010902

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 2| Part 7| July 2017| x171090

https://doi.org/10.1107/S2414314617010902

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5-Methylpyrazine-2-carboxamide

D. Paul Rillema,^a ^* Nilmini K. Senaratne,^a Curtis Moore ^b and Venugopal KomReddy ^a

^aDepartment of Chemistry, Wichita State University, Wichita, KS 67260, USA, and ^bCrystallographic laboratory, University of California, San Diego, LaJolla, CA 92093, USA
^*Correspondence e-mail: paul.rillema@wichita.edu

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 13 July 2017; accepted 24 July 2017; online 28 July 2017)

The title compound, C₆H₇N₃O, is nearly planar, with a dihedral angle of 2.14 (11)° between the pyrazine ring and the mean plane of the carboxamide group [C—C(=O)—N]. In the crystal, molecules are linked via pairs of N—H⋯O hydrogen bonds forming inversion dimers with an R₂²(8) ring motif. These dimers are further linked by a pair of N—H⋯N hydrogen bonds, enclosing an R₂²(10) ring motif, and C—H⋯O hydrogen bonds, forming ribbons lying parallel to the ab plane. The ribbons are linked by offset π–π interactions [intercentroid distance = 3.759 (1) Å], forming two sets of mutually perpendicular slabs parallel to planes (110) and (1-10).

Keywords: crystal structure; amide; pyrazine; hydrogen bonding.

CCDC reference: 1564289

Structure description

The title compound, is an intermediate in the preparation of 2-bromo-5-methylpyrazine (Madhusudhan et al., 2009 ). The latter compound has been used to synthesize 5,5′-dimethyl-2,2′-bipyrazine (Pefkianakis et al., 2008 ) derivatives as bidentate ligands to coordinate to transition metals. The molecular structure of the title compound is illustrated in Fig. 1. The bond lengths of the methylpyrazine component are similar to those found in methyl 5-methyl-2-pyrazinecarboxylate (Rillema et al., 2017 ). The molecule is planar with a dihedral angle of 2.14 (11)° between the pyrazine ring (N2/N3/C2–C5) and the mean plane of the carboxamide group [atoms C2—C1(=O1)—N1].

Figure 1
The molecular structure of the title compound, with the atom labelling and 50% probability displacement ellipsoids.

In the crystal, molecules are linked via pairs of N—H⋯O hydrogen bonds, forming classical amide–amide inversion dimers with an R₂²(8) ring motif (Table 1 and Fig. 2). These dimers are further linked by pairs of N—H⋯N hydrogen bonds, enclosing R₂²(10) ring motifs, and C—H⋯O hydrogen bonds, forming ribbons lying parallel to (001); see Table 1 and Fig. 2. The ribbons are linked in the a-axis direction by offset π–π interactions, forming two sets of mutually perpendicular slabs parallel to (110) and (1 $[\overline{1}]$ 0), as shown in Fig. 3 [Cg⋯Cg^i,ii = 3.759 (1) Å, Cg is the centroid of the pyrazine ring, interplanar distance = 3.386 (1) Å, slippage = 1.63 Å, symmetry codes: (i) −1 + x, y, z; (ii) 1 + x, y, z].

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯O1ⁱ	0.94 (2)	1.96 (2)	2.905 (2)	178 (2)
N1—H1A⋯N2ⁱⁱ	0.92 (2)	2.34 (2)	3.072 (2)	136 (2)
C4—H4⋯O1ⁱⁱⁱ	0.95	2.40	3.339 (3)	168
Symmetry codes: (i) -x+2, -y+2, -z+1; (ii) -x+1, -y+1, -z+1; (iii) x-1, y-1, z.

Figure 2
A view along the a axis of the crystal packing of the title compound. The hydrogen bonds are shown as dashed lines (see Table 1

Figure 3
A view normal to the ab plane of the crystal packing of the title compound. Hydrogen bonds are shown as dashed lines (see Table 1

Synthesis and crystallization

Methyl 5-methyl-2-pyrazinecarboxylate (80.0 g, 0.657 mole) (Rillema et al., 2017) was added to 600 ml of methanol in a 1 litre round-bottomed flask. The flask was immersed in an ice bath, the contents were cooled to ca 273 K, stirred with a magnetic stirrer and then purged with ammonia gas for 4 h. The reaction progress was monitored by thin-layer chromatography (TLC). After completion of the reaction, the product was separated by filtration and washed with pre-cooled methanol (2 × 30 ml) to give the title compound as a light-brown coloured solid. It was recrystallized by dissolving a small amount in methanol and then allowing the methanol to evaporate slowly, yielding colourless needles.

Refinement

Crystal data, data collection and refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₆H₇N₃O
M_r	137.15
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	100
a, b, c (Å)	3.7592 (9), 6.7317 (13), 25.290 (5)
β (°)	93.106 (14)
V (Å³)	639.0 (2)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.10
Crystal size (mm)	0.22 × 0.11 × 0.09

Data collection
Diffractometer	Bruker X8 APEXII
Absorption correction	Multi-scan (SADABS; Bruker, 2013 )
T_min, T_max	0.218, 0.259
No. of measured, independent and observed [I > 2σ(I)] reflections	7302, 1182, 849
R_int	0.046
(sin θ/λ)_max (Å⁻¹)	0.604

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.104, 1.03
No. of reflections	1182
No. of parameters	100
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.20, −0.21
Computer programs: APEX2 and SAINT (Bruker, 2013), SAINT (Bruker, 2013), SHELXT (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ), OLEX2 (Dolomanov et al., 2009 ), Mercury (Macrae et al., 2008 ) and PLATON (Spek, 2009 ).

Structural data

CCDC reference: 1564289

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2414314617010902/su4158sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617010902/su4158Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314617010902/su4158Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2013); cell refinement: SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2008); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) and PLATON (Spek, 2009).

5-Methylpyrazine-2-carboxamide top

Crystal data top

C₆H₇N₃O	F(000) = 288
M_r = 137.15	D_x = 1.425 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 3.7592 (9) Å	Cell parameters from 1367 reflections
b = 6.7317 (13) Å	θ = 3.1–24.9°
c = 25.290 (5) Å	µ = 0.10 mm⁻¹
β = 93.106 (14)°	T = 100 K
V = 639.0 (2) Å³	Needle, colourless
Z = 4	0.22 × 0.11 × 0.09 mm

Data collection top

Bruker X8 APEXII diffractometer	1182 independent reflections
Radiation source: sealed tube, fine-focus	849 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.046
Detector resolution: 7.9 pixels mm^-1	θ_max = 25.4°, θ_min = 3.1°
ω and φ scans	h = −4→4
Absorption correction: multi-scan (SADABS; Bruker, 2013)	k = −8→8
T_min = 0.218, T_max = 0.259	l = −30→30
7302 measured reflections

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.043	Hydrogen site location: mixed
wR(F²) = 0.104	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ²(F_o²) + (0.0525P)² + 0.1949P] where P = (F_o² + 2F_c²)/3
1182 reflections	(Δ/σ)_max < 0.001
100 parameters	Δρ_max = 0.20 e Å⁻³
2 restraints	Δρ_min = −0.21 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
O1	0.9776 (4)	0.95545 (19)	0.42480 (5)	0.0240 (4)
N1	0.7790 (5)	0.7706 (3)	0.49219 (7)	0.0237 (5)
H1A	0.668 (5)	0.654 (3)	0.5011 (9)	0.034 (6)*
H1B	0.853 (6)	0.861 (3)	0.5190 (8)	0.039 (7)*
N2	0.5554 (4)	0.4823 (2)	0.42240 (6)	0.0179 (4)
N3	0.6419 (4)	0.5310 (2)	0.31371 (6)	0.0183 (4)
C1	0.8296 (5)	0.8043 (3)	0.44120 (7)	0.0181 (5)
C2	0.7022 (5)	0.6467 (3)	0.40302 (7)	0.0155 (5)
C3	0.7440 (5)	0.6691 (3)	0.34927 (7)	0.0176 (5)
H3	0.8497	0.7877	0.3372	0.021*
C4	0.4559 (5)	0.3434 (3)	0.38712 (7)	0.0177 (5)
H4	0.3536	0.2241	0.3994	0.021*
C5	0.4955 (5)	0.3657 (3)	0.33261 (7)	0.0164 (5)
C6	0.3727 (5)	0.2094 (3)	0.29402 (8)	0.0229 (5)
H6A	0.1921	0.2653	0.2689	0.034*
H6B	0.2696	0.0984	0.3131	0.034*
H6C	0.5755	0.1619	0.2748	0.034*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0332 (9)	0.0174 (7)	0.0215 (8)	−0.0117 (6)	0.0037 (6)	0.0002 (6)
N1	0.0357 (11)	0.0195 (9)	0.0161 (9)	−0.0138 (8)	0.0031 (8)	−0.0022 (8)
N2	0.0205 (10)	0.0153 (8)	0.0179 (9)	−0.0030 (7)	0.0007 (7)	0.0014 (7)
N3	0.0186 (9)	0.0183 (8)	0.0179 (9)	−0.0014 (7)	0.0001 (7)	0.0000 (7)
C1	0.0180 (11)	0.0173 (10)	0.0190 (11)	−0.0019 (9)	0.0005 (9)	0.0005 (8)
C2	0.0141 (11)	0.0146 (10)	0.0176 (10)	−0.0003 (8)	−0.0014 (8)	0.0008 (8)
C3	0.0166 (11)	0.0167 (9)	0.0194 (11)	−0.0029 (8)	0.0017 (9)	0.0038 (8)
C4	0.0199 (11)	0.0127 (9)	0.0206 (11)	−0.0029 (8)	0.0026 (9)	0.0005 (8)
C5	0.0123 (10)	0.0168 (10)	0.0200 (11)	0.0004 (8)	0.0009 (8)	−0.0009 (8)
C6	0.0225 (12)	0.0243 (11)	0.0223 (11)	−0.0050 (9)	0.0035 (9)	−0.0059 (9)

Geometric parameters (Å, º) top

O1—C1	1.241 (2)	C2—C3	1.385 (3)
N1—H1A	0.923 (16)	C3—H3	0.9500
N1—H1B	0.941 (16)	C4—H4	0.9500
N1—C1	1.333 (2)	C4—C5	1.403 (3)
N2—C2	1.341 (2)	C5—C6	1.491 (3)
N2—C4	1.332 (2)	C6—H6A	0.9800
N3—C3	1.335 (2)	C6—H6B	0.9800
N3—C5	1.341 (2)	C6—H6C	0.9800
C1—C2	1.496 (3)

H1A—N1—H1B	120 (2)	C2—C3—H3	118.6
C1—N1—H1A	118.2 (14)	N2—C4—H4	118.6
C1—N1—H1B	122.3 (14)	N2—C4—C5	122.85 (17)
C4—N2—C2	116.15 (16)	C5—C4—H4	118.6
C3—N3—C5	116.50 (16)	N3—C5—C4	120.43 (17)
O1—C1—N1	123.55 (18)	N3—C5—C6	118.08 (17)
O1—C1—C2	119.96 (16)	C4—C5—C6	121.48 (17)
N1—C1—C2	116.48 (16)	C5—C6—H6A	109.5
N2—C2—C1	118.25 (16)	C5—C6—H6B	109.5
N2—C2—C3	121.26 (17)	C5—C6—H6C	109.5
C3—C2—C1	120.47 (16)	H6A—C6—H6B	109.5
N3—C3—C2	122.80 (17)	H6A—C6—H6C	109.5
N3—C3—H3	118.6	H6B—C6—H6C	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O1ⁱ	0.94 (2)	1.96 (2)	2.905 (2)	178 (2)
N1—H1A···N2ⁱⁱ	0.92 (2)	2.34 (2)	3.072 (2)	136 (2)
C4—H4···O1ⁱⁱⁱ	0.95	2.40	3.339 (3)	168

Symmetry codes: (i) −x+2, −y+2, −z+1; (ii) −x+1, −y+1, −z+1; (iii) x−1, y−1, z.

Funding information

We are grateful for support from the National Science Foundation (EPSCoR), the Wichita State University Office of Research and the Department of Energy.

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