Methyl 5-methyl­pyrazine-2-carboxyl­ate

Rillema, D.P.; KomReddy, V.; Senaratne, N.K.; Eichhorn, D.M.

doi:10.1107/S241431461700997X

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 2| Part 7| July 2017| x170997

https://doi.org/10.1107/S241431461700997X

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Methyl 5-methylpyrazine-2-carboxylate

D. Paul Rillema,^a ^* Venugopal KomReddy,^a Nilmini K. Senaratne ^a and David M. Eichhorn ^a

^aDepartment of Chemistry, Wichita State University, Wichita, KS 67260, USA
^*Correspondence e-mail: paul.rillema@wichita.edu

Edited by J. Simpson, University of Otago, New Zealand (Received 28 June 2017; accepted 5 July 2017; online 13 July 2017)

In the structure of methyl 5-methyl-2-pyrazinecarboxylate, C₇H₈N₂O₂, the non-H atoms of the molecule are nearly planar, with a dihedral angle of 5.4 (1)° between the plane of the pyrazine ring and the plane defined by C—C(O)—O. In the crystal, molecules are linked via C—H⋯N and C—H⋯O hydrogen bonds, forming layers parallel to (100).

Keywords: crystal structure; pyrazine; hydrogen bonding.

CCDC reference: 1560429

Structure description

The title compound, Fig. 1, is an intermediate in the preparation of 5,5′-dimethyl-2,2′-bipyrazine derivatives used to coordinate to transition metals for use in solar energy conversion studies (Toma et al., 2004 ; Rillema et al., 2007 ; Kirgan et al., 2007 ). The bond lengths of the methyl pyrazine component are similar to those found in 5,5-dimethyl-2,2′-bipyrazine (Eller et al., 2004 ).

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

Two identical molecules are located in the unit cell related to each other by a twofold screw axis. In the crystal, molecules are linked by C—H⋯N and C—H⋯O hydrogen bonds (Table 1), forming sheets parallel to the (100) plane, Fig. 2. The sheets are further linked by C—H⋯N and C—H⋯O hydrogen bonds, forming a three-dimensional network, Fig. 3.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1ⁱ—H1Aⁱ⋯N2ⁱ	0.98	2.72	3.592	148
C1ⁱ—H1Bⁱ⋯O1ⁱ	0.98	2.55	3.455	154
C3ⁱ—H3ⁱ⋯O1ⁱ	0.95	2.41	3.299	155
Symmetry code: (i) $[-x, y+{\script{1\over 2}}, -z]$ .

Figure 2
A view normal to the (100) plane of the crystal packing of the title compound. C—H⋯N (blue) and C—H⋯O (red) hydrogen bonds are shown as dashed lines.

Figure 3
A view of the plane (101) of the crystal packing of the title compound. Hydrogen bonds are shown as dashed lines.

Synthesis and crystallization

The procedure followed one reported earlier (Madhusudhan et al. 2009 ) To a stirred solution of 5–methylpyrazine-2-carboxylic acid (50 g, 0.362 mol) in methanol (150 ml) at 0–5° C, concentrated sulfuric acid (4 ml) was added dropwise. After addition of sulfuric acid was complete, the reaction mixture was stirred at 65° C for 8 h. Then the solution was cooled to room temperature and excess methanol was removed from the solution by rotary evaporation at 30° C. The crude compound was partitioned between water (200 ml) and toluene (300 ml). The water layer was separated from the toluene layer and extracted with toluene (3 × 200 ml). The combined organic layers were washed with 2% aqueous sodium hydroxide solution (50 ml), dried over sodium sulfate, filtered and concentrated under vacuum at below 50° C to give the desired compound as a light-brown colored solid; 82% yield: The crystals were grown using the vapor diffusion technique. The inner vial contained methyl 5-methyl-2-pyrazinecarboxylate in dichloromethane (DCM) and the outer vial contained methanol. The crystals were harvested from the inner vial after 36 h.

Refinement

Crystal data, data collection and refinement details are summarized in Table 2. One low angle reflection with F_o <<< Fc may have been affected by the beamstop and was omitted from the final cycles of refinement.

Table 2
Experimental details

Crystal data
Chemical formula	C₇H₈N₂O₂
M_r	152.15
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	150
a, b, c (Å)	3.8872 (1), 6.8386 (3), 13.6279 (5)
β (°)	93.303 (2)
V (Å³)	361.67 (2)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.11
Crystal size (mm)	0.66 × 0.65 × 0.56

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Numerical (SADABS; Bruker, 2012 )
T_min, T_max	0.925, 0.976
No. of measured, independent and observed [I > 2σ(I)] reflections	9931, 1556, 1495
R_int	0.015
(sin θ/λ)_max (Å⁻¹)	0.641

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.029, 0.083, 1.14
No. of reflections	1556
No. of parameters	102
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.20, −0.17
Absolute structure	Flack x determined using 659 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al, 2013 )
Absolute structure parameter	0.0 (2)
Computer programs: SMART and SAINT (Bruker, 2012), SHELXT (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 1560429

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S241431461700997X/sj4126sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S241431461700997X/sj4126Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S241431461700997X/sj4126Isup3.cml

checkCIF report

Computing details top

Data collection: SMART (Bruker, 2012); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); 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); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Methyl 5-methylpyrazine-2-carboxylate top

Crystal data top

C₇H₈N₂O₂	F(000) = 160
M_r = 152.15	D_x = 1.397 Mg m⁻³
Monoclinic, P2₁	Mo Kα radiation, λ = 0.71073 Å
a = 3.8872 (1) Å	Cell parameters from 7189 reflections
b = 6.8386 (3) Å	θ = 3.0–27.0°
c = 13.6279 (5) Å	µ = 0.11 mm⁻¹
β = 93.303 (2)°	T = 150 K
V = 361.67 (2) Å³	Block, clear colourless
Z = 2	0.66 × 0.65 × 0.56 mm

Data collection top

Bruker APEXII CCD diffractometer	1556 independent reflections
Radiation source: sealed X-ray tube	1495 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.015
Detector resolution: 5.6 pixels mm^-1	θ_max = 27.1°, θ_min = 3.3°
φ and ω scans	h = −4→4
Absorption correction: numerical (SADABS; Bruker, 2012)	k = −8→8
T_min = 0.925, T_max = 0.976	l = −17→17
9931 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.029	w = 1/[σ²(F_o²) + (0.0504P)² + 0.0328P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.083	(Δ/σ)_max < 0.001
S = 1.14	Δρ_max = 0.20 e Å⁻³
1556 reflections	Δρ_min = −0.17 e Å⁻³
102 parameters	Absolute structure: Flack x determined using 659 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al, 2013)
1 restraint	Absolute structure parameter: 0.0 (2)
Primary atom site location: structure-invariant direct methods

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
O2	0.2766 (3)	0.74768 (19)	0.59049 (8)	0.0235 (3)
O1	0.5934 (4)	0.8742 (2)	0.71764 (10)	0.0338 (4)
N2	0.3528 (4)	0.4025 (2)	0.89293 (10)	0.0223 (3)
N1	0.1414 (4)	0.4246 (2)	0.69310 (10)	0.0211 (3)
C6	0.4125 (4)	0.7469 (3)	0.68198 (12)	0.0204 (4)
C4	0.3192 (4)	0.5692 (2)	0.73882 (12)	0.0182 (4)
C3	0.0722 (4)	0.2702 (3)	0.74819 (12)	0.0216 (4)
H3	−0.0525	0.1642	0.7184	0.026*
C2	0.1754 (4)	0.2572 (2)	0.84819 (12)	0.0194 (4)
C1	0.0880 (5)	0.0836 (3)	0.90848 (13)	0.0267 (4)
H1A	0.2996	0.0283	0.9397	0.040*
H1B	−0.0271	−0.0151	0.8660	0.040*
H1C	−0.0660	0.1238	0.9593	0.040*
C5	0.4222 (5)	0.5576 (3)	0.83769 (12)	0.0222 (4)
H5	0.5466	0.6639	0.8673	0.027*
C7	0.3671 (5)	0.9159 (3)	0.53238 (13)	0.0288 (4)
H7A	0.2383	0.9115	0.4685	0.043*
H7B	0.6148	0.9136	0.5225	0.043*
H7C	0.3093	1.0361	0.5669	0.043*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O2	0.0286 (6)	0.0210 (6)	0.0206 (6)	−0.0053 (5)	−0.0005 (5)	0.0025 (5)
O1	0.0461 (9)	0.0243 (7)	0.0299 (7)	−0.0160 (7)	−0.0087 (6)	0.0030 (6)
N2	0.0241 (7)	0.0227 (7)	0.0197 (6)	−0.0011 (7)	−0.0008 (5)	−0.0011 (6)
N1	0.0240 (7)	0.0191 (7)	0.0200 (7)	−0.0038 (6)	−0.0006 (6)	−0.0012 (6)
C6	0.0219 (8)	0.0176 (8)	0.0215 (8)	0.0000 (7)	0.0004 (6)	0.0005 (7)
C4	0.0178 (8)	0.0162 (8)	0.0207 (8)	−0.0001 (6)	0.0012 (6)	−0.0011 (6)
C3	0.0242 (9)	0.0184 (8)	0.0220 (8)	−0.0050 (7)	−0.0003 (6)	−0.0018 (7)
C2	0.0165 (8)	0.0194 (8)	0.0225 (8)	0.0002 (7)	0.0018 (6)	0.0009 (7)
C1	0.0286 (10)	0.0258 (10)	0.0253 (9)	−0.0047 (8)	−0.0017 (7)	0.0079 (7)
C5	0.0249 (9)	0.0187 (8)	0.0225 (8)	−0.0023 (7)	−0.0018 (7)	−0.0029 (7)
C7	0.0343 (10)	0.0257 (9)	0.0264 (9)	−0.0040 (9)	0.0016 (7)	0.0085 (8)

Geometric parameters (Å, º) top

O2—C6	1.3259 (19)	C3—C2	1.401 (2)
O2—C7	1.451 (2)	C2—C1	1.494 (2)
O1—C6	1.203 (2)	C1—H1A	0.9800
N2—C2	1.337 (2)	C1—H1B	0.9800
N2—C5	1.337 (2)	C1—H1C	0.9800
N1—C4	1.339 (2)	C5—H5	0.9500
N1—C3	1.332 (2)	C7—H7A	0.9800
C6—C4	1.497 (2)	C7—H7B	0.9800
C4—C5	1.386 (2)	C7—H7C	0.9800
C3—H3	0.9500

C6—O2—C7	114.85 (14)	C2—C1—H1A	109.5
C2—N2—C5	116.65 (14)	C2—C1—H1B	109.5
C3—N1—C4	116.01 (13)	C2—C1—H1C	109.5
O2—C6—C4	113.23 (14)	H1A—C1—H1B	109.5
O1—C6—O2	124.67 (16)	H1A—C1—H1C	109.5
O1—C6—C4	122.10 (15)	H1B—C1—H1C	109.5
N1—C4—C6	119.51 (14)	N2—C5—C4	122.43 (16)
N1—C4—C5	121.52 (15)	N2—C5—H5	118.8
C5—C4—C6	118.97 (14)	C4—C5—H5	118.8
N1—C3—H3	118.6	O2—C7—H7A	109.5
N1—C3—C2	122.86 (15)	O2—C7—H7B	109.5
C2—C3—H3	118.6	O2—C7—H7C	109.5
N2—C2—C3	120.52 (15)	H7A—C7—H7B	109.5
N2—C2—C1	117.89 (14)	H7A—C7—H7C	109.5
C3—C2—C1	121.59 (15)	H7B—C7—H7C	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1ⁱ—H1Aⁱ···N2ⁱ	0.98	2.72	3.592	148
C1ⁱ—H1Bⁱ···O1ⁱ	0.98	2.55	3.455	154
C3ⁱ—H3ⁱ···O1ⁱ	0.95	2.41	3.299	155

Symmetry code: (i) −x, y+1/2, −z.

Acknowledgements

We ae 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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