Tetra­ethyl pyrazine-2,3,5,6-tetra­carboxyl­ate

Wang, Y.; Stoeckli-Evans, H.

doi:10.1107/S2414314615021744

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 1| January 2016| x152174

https://doi.org/10.1107/S2414314615021744

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Tetraethyl pyrazine-2,3,5,6-tetracarboxylate

Yi Wang ^a and Helen Stoeckli-Evans ^b ^*

^aInstitute of Chemistry, University of Neuchâtel, Av. de Bellevaux 51, CH-2000 Neuchâtel, Switzerland, and ^bInstutute of Physics, University of Meuchâtel, rue Emile-Argand 11, CH-2000 neuchâtel, Switzerland
^*Correspondence e-mail: helen.stoeckli-evans@unine.ch

Edited by J. Simpson, University of Otago, New Zealand (Received 29 October 2015; accepted 16 November 2015; online 1 January 2016)

The whole molecule of the title compound, C₁₆H₂₀N₂O₈, is generated by inversion symmetry. The adjacent carboxylate groups [C(=O)—O—C] are inclined to the pyrazine ring by 72.40 (10) and 19.64 (10)°, and to one another by 68.21 (12)°. In the crystal, molecules stack along the a-axis direction but there are no significant intermolecular interactions present.

Keywords: crystal structure; pyrazine; tetraethyl pyrazine-2,3,5,6-tetracarboxylate.

CCDC reference: 1440891

Synthesis and crystallization

The title compound (Fig. 1) was prepared by the method of Mager & Berends (1960 ). Colourless crystals were obtained by slow evaporation of a solution in THF (yield 71%; m.p. 375–377 K).

Figure 1
The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level. Unlabelled atoms are related to labelled atoms by the symmetry operation −x, −y, −z + 1.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. H atoms were included in calculated positions and treated as riding atoms: C—H = 0.96–0.97 Å with U_i_so(H) = 1.5U_eq(C) for methyl H atoms and 1.2U_eq(C) for other H atoms.

Table 1
Experimental details

Crystal data
Chemical formula	C₁₆H₂₀N₂O₈
M_r	368.34
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	293
a, b, c (Å)	5.4194 (8), 9.0619 (12), 9.4607 (13)
α, β, γ (°)	81.285 (11), 82.771 (11), 77.208 (11)
V (Å³)	445.80 (11)
Z	1
Radiation type	Mo Kα
μ (mm⁻¹)	0.11
Crystal size (mm)	0.31 × 0.27 × 0.07

Data collection
Diffractometer	STOE IPDS 2 diffractometer
Absorption correction	Multi-scan (MULABS; Spek, 2009 )
T_min, T_max	0.650, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	6815, 2408, 1414
R_int	0.078
(sin θ/λ)_max (Å⁻¹)	0.687

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.124, 0.86
No. of reflections	2408
No. of parameters	121
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.26, −0.21
Computer programs: X-AREA (Stoe & Cie, 2009 ), X-RED32 (Stoe & Cie, 2009), SHELXS2014/6 (Sheldrick, 2008 ), SHELXL2014/6 (Sheldrick, 2015 ), PLATON (Spek, 2009), Mercury (Macrae et al., 2008 ), publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 1440891

Crystal structure: contains datablocks I, New_Global_Publ_Block. DOI: https://doi.org/10.1107/S2414314615021744/sj4001sup1.cif

Supporting information file. DOI: https://doi.org/10.1107/S2414314615021744/sj4001Isup2.cml

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314615021744/sj4001Isup2.hkl

checkCIF report

Computing details top

Data collection: X-AREA (Stoe & Cie, 2009); cell refinement: X-AREA (Stoe & Cie, 2009); data reduction: X-RED32 (Stoe & Cie, 2009); program(s) used to solve structure: SHELXS2014/6 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014/6 (Sheldrick, 2015); molecular graphics: PLATON (Spek, 2009) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014/6 (Sheldrick, 2015), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Tetraethyl pyrazine-2,3,5,6-tetracarboxylate top

Crystal data top

C₁₆H₂₀N₂O₈	Z = 1
M_r = 368.34	F(000) = 194
Triclinic, P1	D_x = 1.372 Mg m⁻³
a = 5.4194 (8) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.0619 (12) Å	Cell parameters from 4119 reflections
c = 9.4607 (13) Å	θ = 2.2–29.5°
α = 81.285 (11)°	µ = 0.11 mm⁻¹
β = 82.771 (11)°	T = 293 K
γ = 77.208 (11)°	Plate, colourless
V = 445.80 (11) Å³	0.31 × 0.27 × 0.07 mm

Data collection top

STOE IPDS 2 diffractometer	2408 independent reflections
Radiation source: fine-focus sealed tube	1414 reflections with I > 2σ(I)
Plane graphite monochromator	R_int = 0.078
φ + ω scans	θ_max = 29.2°, θ_min = 2.2°
Absorption correction: multi-scan (MULABS; Spek, 2009)	h = −7→7
T_min = 0.650, T_max = 1.000	k = −12→12
6815 measured reflections	l = −12→12

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.049	w = 1/[σ²(F_o²) + (0.0654P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.124	(Δ/σ)_max < 0.001
S = 0.86	Δρ_max = 0.26 e Å⁻³
2408 reflections	Δρ_min = −0.21 e Å⁻³
121 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.054 (10)

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	0.4462 (2)	−0.06169 (15)	0.77032 (15)	0.0584 (4)
O2	0.1176 (2)	0.13155 (13)	0.81276 (11)	0.0453 (3)
O3	0.4091 (2)	0.25124 (15)	0.54380 (14)	0.0565 (4)
O4	0.1520 (2)	0.36434 (13)	0.37225 (13)	0.0484 (3)
N1	0.0156 (2)	−0.10741 (14)	0.62316 (14)	0.0384 (3)
C1	0.1213 (3)	0.01462 (17)	0.60885 (16)	0.0361 (3)
C2	0.1086 (3)	0.12084 (17)	0.48617 (16)	0.0367 (3)
C3	0.2530 (3)	0.02424 (17)	0.73804 (17)	0.0396 (4)
C4	0.2194 (4)	0.1491 (2)	0.94406 (18)	0.0507 (4)
H4B	0.3871	0.1728	0.9215	0.061*
H4A	0.2333	0.0552	1.0100	0.061*
C5	0.0414 (5)	0.2756 (2)	1.0102 (2)	0.0679 (6)
H5A	−0.1260	0.2537	1.0266	0.102*
H5B	0.0379	0.3691	0.9466	0.102*
H5C	0.0975	0.2855	1.0999	0.102*
C6	0.2424 (3)	0.25202 (18)	0.47080 (17)	0.0406 (4)
C7	0.2689 (4)	0.4982 (2)	0.3480 (2)	0.0534 (4)
H7A	0.3113	0.5185	0.4388	0.064*
H7B	0.1485	0.5865	0.3092	0.064*
C8	0.5034 (4)	0.4738 (3)	0.2464 (2)	0.0704 (6)
H8A	0.4633	0.4482	0.1583	0.106*
H8B	0.6282	0.3920	0.2884	0.106*
H8C	0.5696	0.5655	0.2270	0.106*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0437 (7)	0.0671 (8)	0.0647 (8)	0.0053 (6)	−0.0225 (6)	−0.0197 (6)
O2	0.0438 (6)	0.0549 (6)	0.0382 (6)	−0.0040 (5)	−0.0117 (5)	−0.0120 (5)
O3	0.0576 (7)	0.0670 (8)	0.0542 (8)	−0.0311 (6)	−0.0183 (6)	0.0004 (6)
O4	0.0471 (6)	0.0465 (6)	0.0540 (7)	−0.0166 (5)	−0.0101 (5)	0.0001 (5)
N1	0.0335 (6)	0.0453 (7)	0.0377 (7)	−0.0098 (6)	−0.0046 (5)	−0.0062 (5)
C1	0.0289 (7)	0.0439 (8)	0.0364 (8)	−0.0067 (6)	−0.0028 (6)	−0.0092 (6)
C2	0.0304 (7)	0.0430 (8)	0.0381 (8)	−0.0088 (6)	−0.0026 (6)	−0.0089 (6)
C3	0.0359 (8)	0.0454 (8)	0.0398 (8)	−0.0111 (7)	−0.0059 (6)	−0.0066 (7)
C4	0.0603 (11)	0.0575 (10)	0.0386 (9)	−0.0127 (9)	−0.0153 (8)	−0.0101 (7)
C5	0.0869 (15)	0.0707 (12)	0.0470 (11)	−0.0080 (11)	−0.0073 (10)	−0.0220 (9)
C6	0.0380 (8)	0.0488 (9)	0.0373 (8)	−0.0135 (7)	−0.0018 (6)	−0.0078 (7)
C7	0.0575 (11)	0.0459 (9)	0.0594 (11)	−0.0184 (8)	−0.0047 (8)	−0.0042 (8)
C8	0.0699 (13)	0.0713 (13)	0.0711 (14)	−0.0281 (11)	0.0059 (11)	−0.0024 (11)

Geometric parameters (Å, º) top

O1—C3	1.2012 (18)	C4—C5	1.487 (3)
O2—C3	1.3212 (19)	C4—H4B	0.9700
O2—C4	1.4642 (18)	C4—H4A	0.9700
O3—C6	1.2026 (19)	C5—H5A	0.9600
O4—C6	1.324 (2)	C5—H5B	0.9600
O4—C7	1.465 (2)	C5—H5C	0.9600
N1—C1	1.3359 (19)	C7—C8	1.490 (3)
N1—C2ⁱ	1.3370 (19)	C7—H7A	0.9700
C1—C2	1.389 (2)	C7—H7B	0.9700
C1—C3	1.513 (2)	C8—H8A	0.9600
C2—N1ⁱ	1.3370 (19)	C8—H8B	0.9600
C2—C6	1.504 (2)	C8—H8C	0.9600

C3—O2—C4	116.24 (12)	H5A—C5—H5B	109.5
C6—O4—C7	117.08 (13)	C4—C5—H5C	109.5
C1—N1—C2ⁱ	116.40 (13)	H5A—C5—H5C	109.5
N1—C1—C2	122.26 (13)	H5B—C5—H5C	109.5
N1—C1—C3	113.45 (13)	O3—C6—O4	125.77 (15)
C2—C1—C3	124.29 (13)	O3—C6—C2	121.82 (15)
N1ⁱ—C2—C1	121.33 (13)	O4—C6—C2	112.39 (13)
N1ⁱ—C2—C6	118.01 (14)	O4—C7—C8	111.08 (15)
C1—C2—C6	120.63 (13)	O4—C7—H7A	109.4
O1—C3—O2	125.92 (15)	C8—C7—H7A	109.4
O1—C3—C1	123.30 (14)	O4—C7—H7B	109.4
O2—C3—C1	110.63 (12)	C8—C7—H7B	109.4
O2—C4—C5	107.54 (15)	H7A—C7—H7B	108.0
O2—C4—H4B	110.2	C7—C8—H8A	109.5
C5—C4—H4B	110.2	C7—C8—H8B	109.5
O2—C4—H4A	110.2	H8A—C8—H8B	109.5
C5—C4—H4A	110.2	C7—C8—H8C	109.5
H4B—C4—H4A	108.5	H8A—C8—H8C	109.5
C4—C5—H5A	109.5	H8B—C8—H8C	109.5
C4—C5—H5B	109.5

C2ⁱ—N1—C1—C2	−1.3 (2)	N1—C1—C3—O2	−105.99 (15)
C2ⁱ—N1—C1—C3	178.62 (12)	C2—C1—C3—O2	73.95 (18)
N1—C1—C2—N1ⁱ	1.4 (2)	C3—O2—C4—C5	179.40 (16)
C3—C1—C2—N1ⁱ	−178.55 (13)	C7—O4—C6—O3	1.3 (2)
N1—C1—C2—C6	−176.59 (14)	C7—O4—C6—C2	−179.88 (13)
C3—C1—C2—C6	3.5 (2)	N1ⁱ—C2—C6—O3	−160.17 (15)
C4—O2—C3—O1	2.1 (2)	C1—C2—C6—O3	17.9 (2)
C4—O2—C3—C1	177.82 (13)	N1ⁱ—C2—C6—O4	21.0 (2)
N1—C1—C3—O1	69.8 (2)	C1—C2—C6—O4	−160.99 (14)
C2—C1—C3—O1	−110.23 (19)	C6—O4—C7—C8	84.0 (2)

Symmetry code: (i) −x, −y, −z+1.

Acknowledgements

We are grateful to the Swiss National Science Foundation and the University of Neuchâtel for financial support.

References

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