Acta Cryst. (2008). E64, o860 [ doi:10.1107/S1600536808009963 ]
In the crystal structure of the title compound, C8H12O6, molecules are linked to each other by O-H
O hydrogen bonding.
0.1 mol 5,6-O,O-Isopropylidene L-ascorbic acid was dissolved in 100 ml DMSO at room temperature, and 0.12 mol NaHCO3 was added with stirring. After the addition of 0.1 mol ethyl bromide, the mixture was stirred at 313 K for 6 h. The solvent was distilled of at 333 K under reduced pressure. The residue was dissolved in 50 ml water and extracted five times with ethyl acetate (100 ml/time). The collected organic phase was dried over Na2SO4 and the solvent was evaporated at reduced pressure. 100 ml 0.1 M HCl was added to the residue, refluxed for 15 min and then the solvent was evaporated at reduced pressure. The residue was dissolved in ethyl acetate; single crystals were obtained by slow evaporation of the ethyl acetate solution.
Hydroxyl H atoms were located in a difference Fourier map and positional parameters were refined, Uiso(H) = 1.5Ueq(O). Other H atoms were positioned geometrically with C—H = 0.96–0.98 Å and refined using a riding model with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C) (for methyl). As no significant anomalous scattering effect, Friedel pairs were merged.
Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
![[Figure 1]](./xu2411fig1thm.gif)
| Fig. 1. The molecular structure of (I), with atom labels and 30% probability displacement ellipsoids for non-H atoms. |
| C8H12O6 | Dx = 1.449 Mg m−3 |
| Mr = 204.18 | Melting point: 385 K |
| Orthorhombic, P212121 | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: P 2ac 2ab | Cell parameters from 25 reflections |
| a = 4.6690 (9) Å | θ = 10–13º |
| b = 11.939 (2) Å | µ = 0.13 mm−1 |
| c = 16.794 (3) Å | T = 293 (2) K |
| V = 936.2 (3) Å3 | Plate, colourless |
| Z = 4 | 0.20 × 0.20 × 0.10 mm |
| F000 = 432 |
| Enraf–Nonius CAD-4 diffractometer | Rint = 0.028 |
| Radiation source: fine-focus sealed tube | θmax = 25.2º |
| Monochromator: graphite | θmin = 2.1º |
| T = 293(2) K | h = 0→5 |
| ω/2θ scans | k = 0→14 |
| Absorption correction: none | l = −20→20 |
| 1973 measured reflections | 3 standard reflections |
| 1024 independent reflections | every 200 reflections |
| 882 reflections with I > 2σ(I) | intensity decay: none |
| 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)] = 0.040 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.138 | w = 1/[σ2(Fo2) + (0.1P)2 + 1.3P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.00 | (Δ/σ)max < 0.001 |
| 1024 reflections | Δρmax = 0.18 e Å−3 |
| 137 parameters | Δρmin = −0.26 e Å−3 |
| 1 restraint | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.121 (14) |
| C8H12O6 | V = 936.2 (3) Å3 |
| Mr = 204.18 | Z = 4 |
| Orthorhombic, P212121 | Mo Kα |
| a = 4.6690 (9) Å | µ = 0.13 mm−1 |
| b = 11.939 (2) Å | T = 293 (2) K |
| c = 16.794 (3) Å | 0.20 × 0.20 × 0.10 mm |
| Enraf–Nonius CAD-4 diffractometer | Rint = 0.028 |
| Absorption correction: none | 3 standard reflections |
| 1973 measured reflections | every 200 reflections |
| 1024 independent reflections | intensity decay: none |
| 882 reflections with I > 2σ(I) |
| R[F2 > 2σ(F2)] = 0.040 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.138 | Δρmax = 0.18 e Å−3 |
| S = 1.00 | Δρmin = −0.26 e Å−3 |
| 1024 reflections | Absolute structure: ? |
| 137 parameters | Flack parameter: ? |
| 1 restraint | Rogers parameter: ? |
Experimental. 1H NMR (500 MHz, CDCl3): δ1.39 (3H, t), 3.86 (2H, m), 3.96 (1H, m), 4.54 (2H, q), 4.71 (1H, d) p.p.m. |
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 | ||
| O1 | 0.5474 (6) | 0.5579 (2) | 0.82156 (13) | 0.0513 (7) | |
| C1 | 0.6281 (17) | 0.6421 (5) | 0.9472 (3) | 0.0896 (18) | |
| H1A | 0.5996 | 0.6352 | 1.0036 | 0.134* | |
| H1B | 0.5371 | 0.7093 | 0.9285 | 0.134* | |
| H1C | 0.8295 | 0.6455 | 0.9359 | 0.134* | |
| O2 | 0.1035 (7) | 0.3667 (2) | 0.85756 (15) | 0.0563 (8) | |
| H2A | 0.027 (12) | 0.305 (2) | 0.851 (3) | 0.084* | |
| C2 | 0.5046 (14) | 0.5463 (4) | 0.90741 (19) | 0.0664 (14) | |
| H2B | 0.3016 | 0.5418 | 0.9192 | 0.080* | |
| H2C | 0.5953 | 0.4782 | 0.9262 | 0.080* | |
| C3 | 0.4076 (7) | 0.4855 (2) | 0.77537 (18) | 0.0385 (8) | |
| O3 | −0.0350 (7) | 0.2854 (2) | 0.69573 (15) | 0.0555 (7) | |
| C4 | 0.2202 (8) | 0.4033 (3) | 0.78834 (19) | 0.0401 (8) | |
| O4 | 0.2730 (6) | 0.41543 (19) | 0.65249 (13) | 0.0451 (7) | |
| C5 | 0.1347 (8) | 0.3595 (3) | 0.7110 (2) | 0.0419 (8) | |
| O5 | 0.0863 (5) | 0.64292 (19) | 0.67658 (15) | 0.0419 (6) | |
| H5A | 0.088 (11) | 0.671 (3) | 0.727 (3) | 0.063* | |
| O6 | 0.3693 (6) | 0.7318 (2) | 0.53918 (14) | 0.0466 (7) | |
| H6A | 0.213 (11) | 0.729 (4) | 0.511 (3) | 0.070* | |
| C6 | 0.4518 (7) | 0.4996 (2) | 0.68745 (17) | 0.0355 (8) | |
| H6B | 0.6523 | 0.4838 | 0.6744 | 0.043* | |
| C7 | 0.3734 (7) | 0.6151 (3) | 0.65672 (17) | 0.0329 (7) | |
| H7A | 0.5026 | 0.6705 | 0.6804 | 0.039* | |
| C8 | 0.4004 (9) | 0.6198 (3) | 0.56722 (18) | 0.0427 (9) | |
| H8A | 0.5861 | 0.5910 | 0.5514 | 0.051* | |
| H8B | 0.2544 | 0.5729 | 0.5432 | 0.051* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| O1 | 0.0599 (17) | 0.0583 (14) | 0.0356 (11) | −0.0134 (14) | −0.0067 (13) | 0.0078 (11) |
| C1 | 0.122 (5) | 0.091 (3) | 0.056 (3) | −0.020 (4) | 0.007 (3) | −0.013 (2) |
| O2 | 0.0731 (19) | 0.0566 (14) | 0.0391 (12) | −0.0154 (17) | 0.0083 (14) | 0.0088 (12) |
| C2 | 0.096 (4) | 0.068 (2) | 0.0350 (16) | −0.016 (3) | −0.005 (2) | 0.0046 (17) |
| C3 | 0.0394 (17) | 0.0395 (15) | 0.0365 (15) | 0.0018 (17) | −0.0037 (15) | 0.0049 (13) |
| O3 | 0.0678 (17) | 0.0441 (13) | 0.0544 (14) | −0.0087 (15) | −0.0043 (15) | 0.0031 (11) |
| C4 | 0.0452 (19) | 0.0366 (16) | 0.0385 (16) | 0.0016 (15) | 0.0020 (16) | 0.0092 (13) |
| O4 | 0.0605 (16) | 0.0383 (12) | 0.0364 (11) | −0.0028 (12) | 0.0032 (12) | 0.0020 (9) |
| C5 | 0.0473 (19) | 0.0352 (15) | 0.0432 (18) | 0.0034 (18) | 0.0011 (17) | 0.0056 (14) |
| O5 | 0.0367 (13) | 0.0485 (12) | 0.0406 (12) | 0.0064 (12) | 0.0060 (11) | 0.0020 (10) |
| O6 | 0.0455 (14) | 0.0504 (13) | 0.0440 (13) | −0.0009 (13) | −0.0044 (12) | 0.0163 (11) |
| C6 | 0.0328 (16) | 0.0358 (15) | 0.0378 (15) | 0.0055 (15) | 0.0032 (14) | 0.0039 (13) |
| C7 | 0.0293 (15) | 0.0367 (15) | 0.0326 (15) | −0.0029 (14) | 0.0023 (13) | 0.0023 (12) |
| C8 | 0.054 (2) | 0.0394 (16) | 0.0345 (16) | 0.0045 (19) | 0.0078 (17) | 0.0044 (14) |
| O1—C3 | 1.332 (4) | C4—C5 | 1.456 (5) |
| O1—C2 | 1.462 (4) | O4—C5 | 1.353 (4) |
| C1—C2 | 1.444 (7) | O4—C6 | 1.432 (4) |
| C1—H1A | 0.9600 | O5—C7 | 1.421 (4) |
| C1—H1B | 0.9600 | O5—H5A | 0.91 (4) |
| C1—H1C | 0.9600 | O6—C8 | 1.425 (4) |
| O2—C4 | 1.356 (4) | O6—H6A | 0.87 (5) |
| O2—H2A | 0.83 (3) | C6—C7 | 1.516 (4) |
| C2—H2B | 0.9700 | C6—H6B | 0.9800 |
| C2—H2C | 0.9700 | C7—C8 | 1.510 (4) |
| C3—C4 | 1.332 (5) | C7—H7A | 0.9800 |
| C3—C6 | 1.500 (4) | C8—H8A | 0.9700 |
| O3—C5 | 1.215 (4) | C8—H8B | 0.9700 |
| C3—O1—C2 | 116.5 (3) | O3—C5—C4 | 129.0 (3) |
| C2—C1—H1A | 109.5 | O4—C5—C4 | 109.9 (3) |
| C2—C1—H1B | 109.5 | C7—O5—H5A | 107 (3) |
| H1A—C1—H1B | 109.5 | C8—O6—H6A | 103 (4) |
| C2—C1—H1C | 109.5 | O4—C6—C3 | 104.2 (2) |
| H1A—C1—H1C | 109.5 | O4—C6—C7 | 111.0 (3) |
| H1B—C1—H1C | 109.5 | C3—C6—C7 | 113.8 (3) |
| C4—O2—H2A | 110 (4) | O4—C6—H6B | 109.2 |
| C1—C2—O1 | 109.1 (4) | C3—C6—H6B | 109.2 |
| C1—C2—H2B | 109.9 | C7—C6—H6B | 109.2 |
| O1—C2—H2B | 109.9 | O5—C7—C8 | 107.7 (3) |
| C1—C2—H2C | 109.9 | O5—C7—C6 | 111.1 (3) |
| O1—C2—H2C | 109.9 | C8—C7—C6 | 110.7 (3) |
| H2B—C2—H2C | 108.3 | O5—C7—H7A | 109.1 |
| O1—C3—C4 | 134.8 (3) | C8—C7—H7A | 109.1 |
| O1—C3—C6 | 115.7 (3) | C6—C7—H7A | 109.1 |
| C4—C3—C6 | 109.5 (3) | O6—C8—C7 | 110.8 (3) |
| C3—C4—O2 | 129.9 (3) | O6—C8—H8A | 109.5 |
| C3—C4—C5 | 107.4 (3) | C7—C8—H8A | 109.5 |
| O2—C4—C5 | 122.6 (3) | O6—C8—H8B | 109.5 |
| C5—O4—C6 | 109.1 (2) | C7—C8—H8B | 109.5 |
| O3—C5—O4 | 121.1 (3) | H8A—C8—H8B | 108.1 |
| C3—O1—C2—C1 | −169.9 (4) | C5—O4—C6—C3 | 1.1 (3) |
| C2—O1—C3—C4 | 3.1 (6) | C5—O4—C6—C7 | −121.7 (3) |
| C2—O1—C3—C6 | 179.3 (3) | O1—C3—C6—O4 | −178.1 (3) |
| O1—C3—C4—O2 | 1.1 (6) | C4—C3—C6—O4 | −0.9 (4) |
| C6—C3—C4—O2 | −175.3 (3) | O1—C3—C6—C7 | −57.1 (4) |
| O1—C3—C4—C5 | 176.8 (4) | C4—C3—C6—C7 | 120.0 (3) |
| C6—C3—C4—C5 | 0.4 (4) | O4—C6—C7—O5 | 61.3 (3) |
| C6—O4—C5—O3 | 178.3 (3) | C3—C6—C7—O5 | −55.8 (4) |
| C6—O4—C5—C4 | −1.0 (4) | O4—C6—C7—C8 | −58.3 (4) |
| C3—C4—C5—O3 | −178.9 (4) | C3—C6—C7—C8 | −175.4 (3) |
| O2—C4—C5—O3 | −2.8 (6) | O5—C7—C8—O6 | 67.1 (4) |
| C3—C4—C5—O4 | 0.3 (4) | C6—C7—C8—O6 | −171.2 (3) |
| O2—C4—C5—O4 | 176.4 (3) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O2—H2A···O5i | 0.83 (3) | 2.06 (3) | 2.873 (3) | 168 (5) |
| O5—H5A···O3ii | 0.91 (5) | 1.90 (4) | 2.748 (4) | 154 (4) |
| O6—H6A···O6iii | 0.87 (5) | 1.87 (5) | 2.715 (4) | 163 (4) |
| Symmetry codes: (i) −x, y−1/2, −z+3/2; (ii) −x, y+1/2, −z+3/2; (iii) x−1/2, −y+3/2, −z+1. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O2—H2A···O5i | 0.83 (3) | 2.06 (3) | 2.873 (3) | 168 (5) |
| O5—H5A···O3ii | 0.91 (5) | 1.90 (4) | 2.748 (4) | 154 (4) |
| O6—H6A···O6iii | 0.87 (5) | 1.87 (5) | 2.715 (4) | 163 (4) |
| Symmetry codes: (i) −x, y−1/2, −z+3/2; (ii) −x, y+1/2, −z+3/2; (iii) x−1/2, −y+3/2, −z+1. |
Enraf–Nonius (1989). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands.
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.
Nihro, Y., Sogawa, S. & Izumi, A. (1992). J. Med. Chem. 35, 1618–1623.
Satoh, T., Niino, Y. & Matsumoto, H. (1994). Jpn Patent JP6228557.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
L-Ascorbic acid has been widely employed as an antioxidant for stabilization of nutrients. However, the low lipophilicity of it and its susceptibility to thermal and oxidative degradation restricts its field of application and has raised considerable interest in the study of ascorbic acid derivatives with increased lipophilicity and stability. The title compound is one of the lipophilic ascorbic acid derivatives, which exhibit antioxidative properties (Nihro et al.,1992) and can be used as antioxidant in food (Satoh et al., 1994). As part of our ongoing study on ascorbic acid derivatives, we report here the crystal structure of the title compound (Fig. 1).
The geometrical parameters of the compound are normal. The C3—C4 bond distance of 1.332 (5) Å and O3—C5 bond distance of 1.215 (4) Å indicate typical C═C and O═C double bonds. Molecules are linked to each other by O—H···O hydrogen bonding (Table 1).