Acta Cryst. (2008). E64, o636 [ doi:10.1107/S1600536808005151 ]
The molecule of the zwitterionic title compound, C6H9NO4S, which lies on a mirror plane, shows a puckered chair conformation of the six-membered ring with the S and N atoms out of the mean plane of the other four C atoms by 0.929 (2) and 0.647 (2) Å, respectively. The ionized carboxyl group is equatorially oriented. The hydrogen-bonding network includes very short O-H
O [2.470 (2) Å] and N-HS [3.471 (2) and 3.416 (2) Å] intermolecular contacts.
(3R,5S)-tetrahydro-2H-1,4-thiazine-3,5-dicarboxylic acid was obtained as described previously (Paglialunga Paradisi et al., 1990). Crystals were grown from a water solution (0.1 mmol in ca 6 ml) by slow evaporation of the solvent.
All H atoms were found in a difference Fourier map. Positional and thermal parameters of all H atoms but H1, which lies in special position and for which Uiso value was set equal to 2.0 Ueq(O1), were refined isotropically.
Data collection: XCS (Colapietro et al., 1992); cell refinement: XCS (Colapietro et al., 1992); data reduction: XCS (Colapietro et al., 1992); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: WinGX (Farrugia, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999).
![[Figure 1]](./rz2198fig1thm.gif)
| Fig. 1. The molecular component in the title compound showing the zwitterion lying on a crystallographic mirror plane and the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. |
![[Figure 2]](./rz2198fig2thm.gif)
| Fig. 2. Packing diagram of the title compound viewed approximately down the a axis. H atoms are shown as small spheres of arbitrary radii. For the sake of clarity, H21, H22, H41 and H42 are omitted. H bonding is indicated by dashed lines. |
| C6H9NO4S | F000 = 400 |
| Mr = 191.21 | Dx = 1.732 Mg m−3 |
| Orthorhombic, Pbnm | Mo Kα radiation λ = 0.71069 Å |
| Hall symbol: -P 2c 2ab | Cell parameters from 87 reflections |
| a = 6.1641 (8) Å | θ = 20–25º |
| b = 9.323 (1) Å | µ = 0.41 mm−1 |
| c = 12.760 (1) Å | T = 298 (2) K |
| V = 733.29 (14) Å3 | Block, colourless |
| Z = 4 | 0.20 × 0.15 × 0.10 mm |
| Huber CS four-circle diffractometer | Rint = 0.02 |
| Radiation source: fine-focus sealed tube | θmax = 30.0º |
| Monochromator: graphite | θmin = 3.2º |
| T = 298(2) K | h = 0→8 |
| ω scans | k = 0→13 |
| Absorption correction: ψ scan (North et al., 1968) | l = 0→17 |
| Tmin = 0.916, Tmax = 0.958 | 3 standard reflections |
| 1840 measured reflections | every 97 reflections |
| 1060 independent reflections | intensity decay: 2% |
| 998 reflections with I > 2σ(I) |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.032 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.094 | w = 1/[σ2(Fo2) + (0.064P)2 + 0.2054P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.07 | (Δ/σ)max < 0.001 |
| 1060 reflections | Δρmax = 0.25 e Å−3 |
| 76 parameters | Δρmin = −0.28 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| C6H9NO4S | V = 733.29 (14) Å3 |
| Mr = 191.21 | Z = 4 |
| Orthorhombic, Pbnm | Mo Kα |
| a = 6.1641 (8) Å | µ = 0.41 mm−1 |
| b = 9.323 (1) Å | T = 298 (2) K |
| c = 12.760 (1) Å | 0.20 × 0.15 × 0.10 mm |
| Huber CS four-circle diffractometer | 998 reflections with I > 2σ(I) |
| Absorption correction: ψ scan (North et al., 1968) | Rint = 0.02 |
| Tmin = 0.916, Tmax = 0.958 | 3 standard reflections |
| 1840 measured reflections | every 97 reflections |
| 1060 independent reflections | intensity decay: 2% |
| R[F2 > 2σ(F2)] = 0.032 | 76 parameters |
| wR(F2) = 0.094 | H atoms treated by a mixture of independent and constrained refinement |
| S = 1.07 | Δρmax = 0.25 e Å−3 |
| 1060 reflections | Δρmin = −0.28 e Å−3 |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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. |
| x | y | z | Uiso*/Ueq | ||
| S1 | 0.04543 (7) | 0.05914 (4) | 0.2500 | 0.01738 (15) | |
| O1 | −0.04198 (17) | −0.42620 (10) | 0.07779 (8) | 0.0235 (2) | |
| H1 | 0.0000 | −0.5000 | 0.0000 | 0.049* | |
| O2 | −0.04168 (16) | −0.23791 (11) | −0.03208 (7) | 0.0233 (2) | |
| N4 | −0.0505 (2) | −0.27615 (15) | 0.2500 | 0.0152 (3) | |
| H41 | 0.077 (5) | −0.316 (4) | 0.2500 | 0.046 (9)* | |
| H42 | −0.129 (5) | −0.344 (3) | 0.2500 | 0.035 (7)* | |
| C2 | 0.0797 (2) | −0.06777 (12) | 0.14454 (10) | 0.0191 (3) | |
| H21 | 0.232 (3) | −0.105 (2) | 0.1441 (12) | 0.031 (4)* | |
| H22 | 0.054 (3) | −0.012 (2) | 0.0759 (16) | 0.029 (5)* | |
| C3 | −0.08019 (18) | −0.19183 (12) | 0.15032 (9) | 0.0154 (2) | |
| H3 | −0.232 (3) | −0.1555 (18) | 0.1489 (11) | 0.019 (4)* | |
| C7 | −0.05172 (18) | −0.29148 (12) | 0.05503 (10) | 0.0167 (2) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| S1 | 0.0253 (2) | 0.0108 (2) | 0.0160 (2) | −0.00097 (13) | 0.000 | 0.000 |
| O1 | 0.0403 (6) | 0.0134 (4) | 0.0170 (4) | 0.0028 (3) | 0.0010 (4) | −0.0023 (3) |
| O2 | 0.0352 (5) | 0.0204 (5) | 0.0142 (4) | −0.0015 (4) | −0.0003 (3) | 0.0006 (3) |
| N4 | 0.0220 (7) | 0.0109 (6) | 0.0127 (6) | −0.0010 (5) | 0.000 | 0.000 |
| C2 | 0.0275 (6) | 0.0142 (5) | 0.0156 (5) | −0.0037 (4) | 0.0027 (4) | −0.0009 (4) |
| C3 | 0.0211 (5) | 0.0126 (4) | 0.0124 (5) | 0.0003 (4) | −0.0012 (4) | 0.0006 (4) |
| C7 | 0.0198 (5) | 0.0156 (5) | 0.0146 (5) | −0.0008 (4) | −0.0011 (4) | −0.0026 (4) |
| S1—C2 | 1.8043 (12) | N4—H41 | 0.87 (3) |
| S1—C2i | 1.8043 (12) | N4—H42 | 0.80 (3) |
| O1—C7 | 1.2905 (14) | C2—C3 | 1.5211 (16) |
| O1—H1 | 1.2352 | C2—H21 | 1.00 (2) |
| O2—C7 | 1.2201 (16) | C2—H22 | 1.03 (2) |
| N4—C3i | 1.5064 (13) | C3—C7 | 1.5403 (16) |
| N4—C3 | 1.5064 (13) | C3—H3 | 0.997 (17) |
| C2—S1—C2i | 96.46 (8) | S1—C2—H22 | 106.5 (11) |
| C7—O1—H1 | 111.77 | H21—C2—H22 | 108.4 (13) |
| C3i—N4—C3 | 115.20 (12) | N4—C3—C2 | 111.04 (10) |
| C3i—N4—H41 | 109.5 (10) | N4—C3—C7 | 109.75 (9) |
| C3—N4—H41 | 109.5 (10) | C2—C3—C7 | 110.28 (9) |
| C3i—N4—H42 | 109.9 (9) | N4—C3—H3 | 107.9 (8) |
| C3—N4—H42 | 109.9 (9) | C2—C3—H3 | 110.5 (10) |
| H41—N4—H42 | 102 (3) | C7—C3—H3 | 107.3 (9) |
| C3—C2—S1 | 112.75 (8) | O2—C7—O1 | 126.95 (11) |
| C3—C2—H21 | 110.2 (12) | O2—C7—C3 | 118.55 (11) |
| S1—C2—H21 | 109.9 (10) | O1—C7—C3 | 114.50 (10) |
| C3—C2—H22 | 108.9 (10) | ||
| C2i—S1—C2—C3 | 56.74 (12) | N4—C3—C7—O2 | −170.39 (11) |
| C3i—N4—C3—C2 | 59.40 (16) | C2—C3—C7—O2 | −47.76 (14) |
| C3i—N4—C3—C7 | −178.42 (8) | N4—C3—C7—O1 | 9.90 (14) |
| S1—C2—C3—N4 | −61.40 (12) | C2—C3—C7—O1 | 132.53 (11) |
| S1—C2—C3—C7 | 176.73 (8) |
| Symmetry codes: (i) x, y, −z+1/2. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O1—H1···O1ii | 1.24 | 1.24 | 2.4704 (19) | 180.00 (9) |
| N4—H41···S1iii | 0.87 (3) | 2.60 (3) | 3.4713 (15) | 179 (3) |
| N4—H42···S1iv | 0.80 (3) | 2.72 (3) | 3.4155 (16) | 147 (3) |
| Symmetry codes: (ii) −x, −y−1, −z; (iii) −x+1/2, y−1/2, z; (iv) −x−1/2, y−1/2, z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O1—H1···O1i | 1.24 | 1.24 | 2.4704 (19) | 180.00 (9) |
| N4—H41···S1ii | 0.87 (3) | 2.60 (3) | 3.4713 (15) | 179 (3) |
| N4—H42···S1iii | 0.80 (3) | 2.72 (3) | 3.4155 (16) | 147 (3) |
| Symmetry codes: (i) −x, −y−1, −z; (ii) −x+1/2, y−1/2, z; (iii) −x−1/2, y−1/2, z. |
We thank MIUR (Rome) for 2006 financial support of the project `X-ray diffractometry and spectrometry'.
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The detection of 1,4-thiomorpholine-3,5-dicarboxylic acid (THT) as normal component in bovin brain (Cavallini, Pecci et al., 1985) and human urine (Matarese et al., 1987) has stimulated the investigation of the biological role played by this unusual cyclic, sulfur containing imino acid (Cavallini et al., 1991). Here we report the x-ray structure determination of the (3R,5S) epymer (THTC). The asymmetric unit of the title compound comprises a half-zwitterion disposed about a mirror plane along the line joining atoms S1 and N4 and perpendicular to the plane formed by C2, C3, C2ì and C3ì [symmetry code: (i) x, y, -z + 1/2]. From Fig. 1 it appears that the six-membered ring adopts a puckered chair conformation with the carboxyl group in equatorial position. The hydrogen-bonding network (Fig. 2) includes very short O—-H···O and N—-H···S (Allen et al., 1997) intermolecular contacts (Table 1).