supplementary materials

sj5320 scheme

Acta Cryst. (2013). E69, o1104    [ doi:10.1107/S1600536813015973 ]


A. H. Haines and D. L. Hughes

Abstract top

The title compound, C7H8N2O2, formed by dehydration of the corresponding dicarboxamide, crystallizes as rectangular prisms. The molecules have a C2 axis of symmetry through the C atom bearing the methyl groups and the mid-point of the ring C-C bond, and the 1,3-dioxolane ring adopts the extreme twist conformation of the two possible with this symmetry. This brings the two nitrile groups nearest to a linear arrangement when the molecule is viewed along the ring C-C bond. The correct absolute configuration of the molecule was defined by that of the original starting material, (2R,3R)-tartaric acid. The packing is largely controlled by a number of C-H...N interactions.

Comment top

The stereoisomeric forms of tartaric acid have played a central role in determining the absolute and relative stereochemistries of chiral carbon compounds, and our knowledge of the absolute configurations of such organic compounds stems from determination of the absolute configuration of the sodium rubidium salt of (+)-tartaric acid (Bijvoet et al., 1951). Since that time, many structural determinations by X-ray crystallography have been performed on derivatives of the three isomeric forms of tartaric acid, the chiral (R,R)- and (S,S)-isomers and the meso (R,S)-isomer. Relevant to our structural determination of the title compound are reports on the crystal structures of: (i) its precursor (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dicarboxamide (Shainyan et al., 2002) - note: the structural diagram in this paper recording the compound's crystallographic data depicts, erroneously, the (4S,5S)-isomer despite the fact that the stated synthesis is from (2R,3R)-tartaric acid); (ii) (2R,3S)-2,3-dihydroxy-2,3-dicyanoethane (Rychlewska et al., 2008); (iii) (2S,3S)-2,3-dibenzoyloxy-2,3-dicyanoethane (Gawroński et al., 2007); and (iv) (2R,3S)-2,3-dibenzoyloxy-2,3-dicyanoethane (Rychlewska et al., 2008).

We previously synthesized (4S,5S)-2,2-dimethyl-1,3-dioxolane-4,5-dicarbonitrile in 80.5% yield as a highly crystalline solid m.p. 163–164 °C by treatment of (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dicarboxamide with benzenesulfonyl chloride in pyridine (Briggs et al., 1985). [N.B. In the paper by Briggs et al., 1985, the stereochemical descriptors for positions 4 and 5 of the dioxolane ring were incorrectly assigned as R; it should be noted that conversion of an amide function into nitrile lowers the order of preference according to the sequence-rules.] Two noteworthy properties of the dicarbonitrile were (i) its resistance to hydrolysis by trifluoroacetic acid-water, an acidic medium which normally brings about ready hydrolysis of the type of acetal group present in this compound, and (ii) the lack of absorptions attributable to a nitrile group in its IR spectrum although an expected absorption was present in its Raman spectrum. Interestingly, (S,S)-2,3-dihydroxy-2,3-dicyanoethane, which was the desired hydrolysis product of the dicarbonitrile, also proved difficult to synthesize from the unprotected (R,R)-tartaric acid diamide, was only obtained in low yield, and is not stable at room temperature (Rychlewska et al., 2008). In contrast, (R,S)-1,2-dihydroxy-1,2-dicyanoethane has been isolated as a stable crystalline solid from the mixture of (R,R), (S,S) and (R,S)-dinitriles obtained in the reaction of glyoxal with potassium cyanide and hydrochloric acid (Rychlewska et al., 2008).

Our molecule has a 5-membered ring with a twist conformation, Figure 1. It lies about a twofold symmetry axis though the Me2-carbon atom C5 and the mid-point of the ring C—C bond. Of the two possible extreme twist conformations which may be so defined that one is adopted which brings the two nitrile groups nearest to linearity with the torsional angle C21—C2—C21—C211 at -155.70 (11)°; the alternative twist conformation would set the nitrile groups with a torsional angle near -90°.

When viewed down the crystallographic a or b axis (Figure 2), intermolecular linear alignment between opposed dipoles of the nitrile groups in neighbouring molecules appears to be a feature of the macro structure of the crystal and might be an attractive explanation for the lack of a nitrile absorption in the IR spectrum of the compound. Thus, dipole moment changes in two parallel (or near parallel) CN groups arranged pointing in opposite directions might "cancel out" leading to a very weak or absent overall absorption for the CN groups. However, the nitrile groups in our structure are not parallel but related by a twofold screw (21) symmetry axis, and the angle between two C–N vectors is 64.35 (8)°.

The absolute configuration of the molecule cannot be determined unequivocally from the X-ray data, but is known from that of the precursor, (2R,3R)-tartaric acid, and is that shown in Figure 1. We note that the Flack x parameter (Flack, 1983) is 0.8 (11), the value of which suggests that we should invert the structure; however, the large s.d. on this value indicates that this parameter has not been reliably determined from the diffraction data.

In contrast to the C2 symmetry possessed by the dinitrile, the dicarboxamide precursor lacks similar symmetry and the shape of its 1,3-dioxolane ring lies close to an envelope conformation with one of the ring O atoms, O2 in the original publication (Shainyan et al., 2002), 0.503 Å out of the mean plane of the remaining ring atoms; extensive inter- and intra-molecular hydrogen bonding occurs involving the amide groups. In our structure, the packing is largely controlled by a number of C–H···N contacts.

The parent (S,S)-1,2-dihydroxy-1,2-dicyanoethane is non-crystalline but the crystal structure of the corresponding (R,S)-1,2-dihydroxy-1,2-dicyanoethane has been reported (Rychlewska et al., 2008) and it has a perfectly staggered conformation about the central C—C bond suggesting that an anti-parallel arrangement of vicinal nitrile groups may be a strong driving force influencing conformational preference and thus influencing the choice of twist conformations in the title compound.

Related literature top

For the first syntheses of the title compound, see: Briggs et al. (1985). For determination of the absolute configuration of (+)-tartaric acid, see: Bijvoet et al. (1951). For related structures, see: (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dicarboxamide, Shainyan et al. (2002); (2R,3S)-2,3-dihydroxy-2,3-dicyanoethane and (2R,3S)-2,3-dibenzoyloxy-2,3-dicyanoethane, Rychlewska et al. (2008); and (2S,3S)-2,3-dibenzoyloxy-2,3-dicyanoethane, Gawroński et al. (2007). For the Flack x parameter, see: Flack (1983).

Experimental top

The preparation of the title compound, m.p. 163–164 °C (sublimes above 120 °C), [α]D -83 (c, 0.6), together with its IR, Raman, and 1H and 13C NMR spectra has been described (Briggs et al., 1985).

Refinement top

The non-hydrogen atoms were refined with anisotropic thermal parameters. All the hydrogen atoms were located in a difference map and were refined freely.

Computing details top

Data collection: CrysAlis PRO CCD (Oxford Diffraction, 2010); cell refinement: CrysAlis PRO RED (Oxford Diffraction, 2010); data reduction: CrysAlis PRO RED (Oxford Diffraction, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPII (Johnson, 1976) and ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and WinGX (Farrugia, 2012).

Figures top
[Figure 1] Fig. 1. View of a molecule of (4S,5S)-2,2-dimethyl-1,3-dioxolane-4,5-dicarbonitrile indicating the atom numbering scheme. Thermal ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. View down the crystallographic a axis showing the apparent alignment of nitrile groups along a twofold screw axis.
(4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-dicarbonitrile top
Crystal data top
C7H8N2O2Dx = 1.309 Mg m3
Mr = 152.15Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P41212Cell parameters from 5971 reflections
Hall symbol: P 4abw 2nwθ = 3.1–32.7°
a = 8.7740 (2) ŵ = 0.10 mm1
c = 10.0282 (3) ÅT = 140 K
V = 772.00 (3) Å3Cube, colourless
Z = 40.08 × 0.07 × 0.07 mm
F(000) = 320
Data collection top
Oxford Diffraction Xcalibur 3/Sapphire3 CCD
1133 independent reflections
Radiation source: Enhance (Mo) X-ray Source1073 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
Detector resolution: 16.0050 pixels mm-1θmax = 30.0°, θmin = 3.1°
Thin–slice φ and ω scansh = 1212
Absorption correction: multi-scan
(CrysAlis PRO RED; Oxford Diffraction, 2010)
k = 1212
Tmin = 0.886, Tmax = 1.000l = 1414
14922 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.030Hydrogen site location: difference Fourier map
wR(F2) = 0.076All H-atom parameters refined
S = 1.09 w = 1/[σ2(Fo2) + (0.0398P)2 + 0.0831P]
where P = (Fo2 + 2Fc2)/3
1133 reflections(Δ/σ)max < 0.001
67 parametersΔρmax = 0.28 e Å3
0 restraintsΔρmin = 0.11 e Å3
Crystal data top
C7H8N2O2Z = 4
Mr = 152.15Mo Kα radiation
Tetragonal, P41212µ = 0.10 mm1
a = 8.7740 (2) ÅT = 140 K
c = 10.0282 (3) Å0.08 × 0.07 × 0.07 mm
V = 772.00 (3) Å3
Data collection top
Oxford Diffraction Xcalibur 3/Sapphire3 CCD
1133 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO RED; Oxford Diffraction, 2010)
1073 reflections with I > 2σ(I)
Tmin = 0.886, Tmax = 1.000Rint = 0.032
14922 measured reflectionsθmax = 30.0°
Refinement top
R[F2 > 2σ(F2)] = 0.030All H-atom parameters refined
wR(F2) = 0.076Δρmax = 0.28 e Å3
S = 1.09Δρmin = 0.11 e Å3
1133 reflectionsAbsolute structure: ?
67 parametersAbsolute structure parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
O10.46094 (8)0.42363 (7)0.38782 (6)0.02318 (17)
C20.53777 (10)0.55849 (10)0.42482 (9)0.02062 (18)
C210.44612 (12)0.69757 (11)0.39872 (10)0.0267 (2)
N210.37695 (12)0.80532 (11)0.37960 (11)0.0416 (3)
C50.37130 (10)0.37130 (10)0.50000.0224 (3)
C510.20468 (13)0.40426 (15)0.47877 (13)0.0359 (3)
H20.6296 (15)0.5652 (14)0.3757 (12)0.026 (3)*
H51A0.1892 (16)0.5121 (18)0.4539 (15)0.045 (4)*
H51B0.151 (2)0.3837 (19)0.5586 (17)0.052 (4)*
H51C0.1670 (19)0.339 (2)0.4073 (19)0.057 (5)*
Atomic displacement parameters (Å2) top
O10.0289 (3)0.0237 (3)0.0169 (3)0.0052 (3)0.0036 (2)0.0023 (2)
C20.0204 (4)0.0208 (4)0.0206 (4)0.0010 (3)0.0000 (3)0.0025 (3)
C210.0264 (5)0.0264 (4)0.0272 (4)0.0018 (4)0.0049 (4)0.0038 (4)
N210.0405 (6)0.0330 (5)0.0513 (7)0.0068 (4)0.0120 (5)0.0053 (5)
C50.0237 (4)0.0237 (4)0.0196 (6)0.0054 (5)0.0034 (3)0.0034 (3)
C510.0230 (5)0.0461 (7)0.0385 (6)0.0066 (5)0.0005 (4)0.0117 (5)
Geometric parameters (Å, º) top
O1—C21.4114 (10)C5—O1i1.4474 (10)
O1—C51.4474 (10)C5—C51i1.5054 (13)
C2—C211.4846 (13)C5—C511.5054 (13)
C2—C2i1.5297 (17)C51—H51A0.988 (15)
C2—H20.946 (13)C51—H51B0.946 (18)
C21—N211.1397 (13)C51—H51C0.975 (19)
C2—O1—C5108.73 (7)O1—C5—C51i108.28 (5)
O1—C2—C21112.59 (7)O1i—C5—C51108.28 (5)
O1—C2—C2i102.49 (5)O1—C5—C51110.91 (6)
C21—C2—C2i109.62 (9)C51i—C5—C51113.15 (13)
O1—C2—H2108.8 (7)C5—C51—H51A110.7 (9)
C21—C2—H2108.6 (7)C5—C51—H51B109.1 (10)
C2i—C2—H2114.8 (8)H51A—C51—H51B109.1 (12)
N21—C21—C2179.18 (12)C5—C51—H51C108.7 (9)
O1i—C5—O1105.03 (10)H51A—C51—H51C109.3 (15)
O1i—C5—C51i110.91 (6)H51B—C51—H51C109.9 (14)
C5—O1—C2—C2188.69 (8)C2—O1—C5—C51104.75 (9)
C5—O1—C2—C2i28.99 (9)O1—C2—C2i—O1i35.25 (11)
C2—O1—C5—O1i12.00 (4)O1—C2—C2i—C21i84.52 (7)
C2—O1—C5—C51i130.54 (9)C21—C2—C2i—C21i155.70 (11)
Symmetry code: (i) y, x, z+1.
Hydrogen-bond geometry (Å, º) top
C2—H2···N21ii0.946 (13)2.450 (13)3.2530 (14)142.6 (10)
Symmetry code: (ii) x+1/2, y+3/2, z+3/4.

Experimental details

Crystal data
Chemical formulaC7H8N2O2
Crystal system, space groupTetragonal, P41212
Temperature (K)140
a, c (Å)8.7740 (2), 10.0282 (3)
V3)772.00 (3)
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.08 × 0.07 × 0.07
Data collection
DiffractometerOxford Diffraction Xcalibur 3/Sapphire3 CCD
Absorption correctionMulti-scan
(CrysAlis PRO RED; Oxford Diffraction, 2010)
Tmin, Tmax0.886, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
14922, 1133, 1073
(sin θ/λ)max1)0.703
R[F2 > 2σ(F2)], wR(F2), S 0.030, 0.076, 1.09
No. of reflections1133
No. of parameters67
No. of restraints0
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.28, 0.11

Computer programs: CrysAlis PRO CCD (Oxford Diffraction, 2010), CrysAlis PRO RED (Oxford Diffraction, 2010), SHELXS97 (Sheldrick, 2008), ORTEPII (Johnson, 1976) and ORTEP-3 for Windows (Farrugia, 2012), SHELXL97 (Sheldrick, 2008) and WinGX (Farrugia, 2012).

Hydrogen-bond geometry (Å, º) top
C2—H2···N21i0.946 (13)2.450 (13)3.2530 (14)142.6 (10)
Symmetry code: (i) x+1/2, y+3/2, z+3/4.
References top

Bijvoet, J. M., Peerdeman, A. F. & van Bommel, A. J. (1951). Nature, 168, 271.

Briggs, M. A., Haines, A. H. & Jones, H. F. (1985). J. Chem. Soc. Perkin Trans. 1, pp. 795–798.

Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.

Flack, H. D. (1983). Acta Cryst. A39, 876–881.

Gawroński, J., Gawrońska, K., Waścinska, N., Plutecka, A. & Rychlewska, U. (2007). Pol. J. Chem. 81, 1917–1925.

Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA.

Oxford Diffraction (2010). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.

Rychlewska, U., Waścinska, N., Warżajtis, B. & Gawroński, J. (2008). Acta Cryst. B64, 497–503.

Shainyan, B. A., Ustinov, M. V., Bel'skii, B. K. & Nindakova, L. O. (2002). Russ. J. Org. Chem. 38, 104–110.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.