organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2414-3146

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

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.

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Synthesis and crystallization

The title compound (Fig. 1[link]) was prepared by the method of Mager & Berends (1960[Mager, H. I. X. & Berends, W. (1960). Recl Trav. Chim. Pays Bas, 79, 282-284.]). Colourless crystals were obtained by slow evaporation of a solution in THF (yield 71%; m.p. 375–377 K).

[Figure 1]
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[link]. H atoms were included in calculated positions and treated as riding atoms: C—H = 0.96–0.97 Å with Uiso(H) = 1.5Ueq(C) for methyl H atoms and 1.2Ueq(C) for other H atoms.

Table 1
Experimental details

Crystal data
Chemical formula C16H20N2O8
Mr 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)
V3) 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[Spek, A. L. (2009). Acta Cryst. D65, 148-155.])
Tmin, Tmax 0.650, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections 6815, 2408, 1414
Rint 0.078
(sin θ/λ)max−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
Δρmax, Δρmin (e Å−3) 0.26, −0.21
Computer programs: X-AREA (Stoe & Cie, 2009[Stoe & Cie. (2009). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany.]), X-RED32 (Stoe & Cie, 2009[Stoe & Cie. (2009). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany.]), SHELXS2014/6 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2014/6 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]), Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]), publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Structural data


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
C16H20N2O8Z = 1
Mr = 368.34F(000) = 194
Triclinic, P1Dx = 1.372 Mg m3
a = 5.4194 (8) ÅMo Kα radiation, λ = 0.71073 Å
b = 9.0619 (12) ÅCell parameters from 4119 reflections
c = 9.4607 (13) Åθ = 2.2–29.5°
α = 81.285 (11)°µ = 0.11 mm1
β = 82.771 (11)°T = 293 K
γ = 77.208 (11)°Plate, colourless
V = 445.80 (11) Å30.31 × 0.27 × 0.07 mm
Data collection top
STOE IPDS 2
diffractometer
2408 independent reflections
Radiation source: fine-focus sealed tube1414 reflections with I > 2σ(I)
Plane graphite monochromatorRint = 0.078
φ + ω scansθmax = 29.2°, θmin = 2.2°
Absorption correction: multi-scan
(MULABS; Spek, 2009)
h = 77
Tmin = 0.650, Tmax = 1.000k = 1212
6815 measured reflectionsl = 1212
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.049 w = 1/[σ2(Fo2) + (0.0654P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.124(Δ/σ)max < 0.001
S = 0.86Δρmax = 0.26 e Å3
2408 reflectionsΔρmin = 0.21 e Å3
121 parametersExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction 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
xyzUiso*/Ueq
O10.4462 (2)0.06169 (15)0.77032 (15)0.0584 (4)
O20.1176 (2)0.13155 (13)0.81276 (11)0.0453 (3)
O30.4091 (2)0.25124 (15)0.54380 (14)0.0565 (4)
O40.1520 (2)0.36434 (13)0.37225 (13)0.0484 (3)
N10.0156 (2)0.10741 (14)0.62316 (14)0.0384 (3)
C10.1213 (3)0.01462 (17)0.60885 (16)0.0361 (3)
C20.1086 (3)0.12084 (17)0.48617 (16)0.0367 (3)
C30.2530 (3)0.02424 (17)0.73804 (17)0.0396 (4)
C40.2194 (4)0.1491 (2)0.94406 (18)0.0507 (4)
H4B0.38710.17280.92150.061*
H4A0.23330.05521.01000.061*
C50.0414 (5)0.2756 (2)1.0102 (2)0.0679 (6)
H5A0.12600.25371.02660.102*
H5B0.03790.36910.94660.102*
H5C0.09750.28551.09990.102*
C60.2424 (3)0.25202 (18)0.47080 (17)0.0406 (4)
C70.2689 (4)0.4982 (2)0.3480 (2)0.0534 (4)
H7A0.31130.51850.43880.064*
H7B0.14850.58650.30920.064*
C80.5034 (4)0.4738 (3)0.2464 (2)0.0704 (6)
H8A0.46330.44820.15830.106*
H8B0.62820.39200.28840.106*
H8C0.56960.56550.22700.106*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0437 (7)0.0671 (8)0.0647 (8)0.0053 (6)0.0225 (6)0.0197 (6)
O20.0438 (6)0.0549 (6)0.0382 (6)0.0040 (5)0.0117 (5)0.0120 (5)
O30.0576 (7)0.0670 (8)0.0542 (8)0.0311 (6)0.0183 (6)0.0004 (6)
O40.0471 (6)0.0465 (6)0.0540 (7)0.0166 (5)0.0101 (5)0.0001 (5)
N10.0335 (6)0.0453 (7)0.0377 (7)0.0098 (6)0.0046 (5)0.0062 (5)
C10.0289 (7)0.0439 (8)0.0364 (8)0.0067 (6)0.0028 (6)0.0092 (6)
C20.0304 (7)0.0430 (8)0.0381 (8)0.0088 (6)0.0026 (6)0.0089 (6)
C30.0359 (8)0.0454 (8)0.0398 (8)0.0111 (7)0.0059 (6)0.0066 (7)
C40.0603 (11)0.0575 (10)0.0386 (9)0.0127 (9)0.0153 (8)0.0101 (7)
C50.0869 (15)0.0707 (12)0.0470 (11)0.0080 (11)0.0073 (10)0.0220 (9)
C60.0380 (8)0.0488 (9)0.0373 (8)0.0135 (7)0.0018 (6)0.0078 (7)
C70.0575 (11)0.0459 (9)0.0594 (11)0.0184 (8)0.0047 (8)0.0042 (8)
C80.0699 (13)0.0713 (13)0.0711 (14)0.0281 (11)0.0059 (11)0.0024 (11)
Geometric parameters (Å, º) top
O1—C31.2012 (18)C4—C51.487 (3)
O2—C31.3212 (19)C4—H4B0.9700
O2—C41.4642 (18)C4—H4A0.9700
O3—C61.2026 (19)C5—H5A0.9600
O4—C61.324 (2)C5—H5B0.9600
O4—C71.465 (2)C5—H5C0.9600
N1—C11.3359 (19)C7—C81.490 (3)
N1—C2i1.3370 (19)C7—H7A0.9700
C1—C21.389 (2)C7—H7B0.9700
C1—C31.513 (2)C8—H8A0.9600
C2—N1i1.3370 (19)C8—H8B0.9600
C2—C61.504 (2)C8—H8C0.9600
C3—O2—C4116.24 (12)H5A—C5—H5B109.5
C6—O4—C7117.08 (13)C4—C5—H5C109.5
C1—N1—C2i116.40 (13)H5A—C5—H5C109.5
N1—C1—C2122.26 (13)H5B—C5—H5C109.5
N1—C1—C3113.45 (13)O3—C6—O4125.77 (15)
C2—C1—C3124.29 (13)O3—C6—C2121.82 (15)
N1i—C2—C1121.33 (13)O4—C6—C2112.39 (13)
N1i—C2—C6118.01 (14)O4—C7—C8111.08 (15)
C1—C2—C6120.63 (13)O4—C7—H7A109.4
O1—C3—O2125.92 (15)C8—C7—H7A109.4
O1—C3—C1123.30 (14)O4—C7—H7B109.4
O2—C3—C1110.63 (12)C8—C7—H7B109.4
O2—C4—C5107.54 (15)H7A—C7—H7B108.0
O2—C4—H4B110.2C7—C8—H8A109.5
C5—C4—H4B110.2C7—C8—H8B109.5
O2—C4—H4A110.2H8A—C8—H8B109.5
C5—C4—H4A110.2C7—C8—H8C109.5
H4B—C4—H4A108.5H8A—C8—H8C109.5
C4—C5—H5A109.5H8B—C8—H8C109.5
C4—C5—H5B109.5
C2i—N1—C1—C21.3 (2)N1—C1—C3—O2105.99 (15)
C2i—N1—C1—C3178.62 (12)C2—C1—C3—O273.95 (18)
N1—C1—C2—N1i1.4 (2)C3—O2—C4—C5179.40 (16)
C3—C1—C2—N1i178.55 (13)C7—O4—C6—O31.3 (2)
N1—C1—C2—C6176.59 (14)C7—O4—C6—C2179.88 (13)
C3—C1—C2—C63.5 (2)N1i—C2—C6—O3160.17 (15)
C4—O2—C3—O12.1 (2)C1—C2—C6—O317.9 (2)
C4—O2—C3—C1177.82 (13)N1i—C2—C6—O421.0 (2)
N1—C1—C3—O169.8 (2)C1—C2—C6—O4160.99 (14)
C2—C1—C3—O1110.23 (19)C6—O4—C7—C884.0 (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

First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationMager, H. I. X. & Berends, W. (1960). Recl Trav. Chim. Pays Bas, 79, 282–284.  CrossRef CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationStoe & Cie. (2009). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany.  Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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