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

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ISSN: 2056-9890

3-O-Ethyl-L-ascorbic acid

aNanjing Research Institute for Comprehensive Utilization of Wild Plants, Jiangwangmiaojie 4#, Nanjing 210042, People's Republic of China
*Correspondence e-mail: sjinlab@msn.com

(Received 27 March 2008; accepted 11 April 2008; online 16 April 2008)

In the crystal structure of the title compound, C8H12O6, mol­ecules are linked to each other by O—H⋯O hydrogen bonding.

Related literature

For general background, see: Nihro et al. (1992[Nihro, Y., Sogawa, S. & Izumi, A. (1992). J. Med. Chem. 35, 1618-1623.]); Satoh et al. (1994[Satoh, T., Niino, Y. & Matsumoto, H. (1994). Jpn Patent JP6228557.]).

[Scheme 1]

Experimental

Crystal data
  • C8H12O6

  • Mr = 204.18

  • Orthorhombic, P 21 21 21

  • a = 4.6690 (9) Å

  • b = 11.939 (2) Å

  • c = 16.794 (3) Å

  • V = 936.2 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.13 mm−1

  • T = 293 (2) K

  • 0.20 × 0.20 × 0.10 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: none

  • 1973 measured reflections

  • 1024 independent reflections

  • 882 reflections with I > 2σ(I)

  • Rint = 0.028

  • 3 standard reflections every 200 reflections intensity decay: none

Refinement
  • R[F2 > 2σ(F2)] = 0.040

  • wR(F2) = 0.138

  • S = 1.00

  • 1024 reflections

  • 137 parameters

  • 1 restraint

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.18 e Å−3

  • Δρmin = −0.26 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA 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-{\script{1\over 2}}, -z+{\script{3\over 2}}]; (ii) [-x, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]; (iii) [x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1].

Data collection: CAD-4 Software (Enraf–Nonius, 1989[Enraf-Nonius (1989). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

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 CC and OC double bonds. Molecules are linked to each other by O—H···O hydrogen bonding (Table 1).

Related literature top

For general background, see: Nihro et al. (1992); Satoh et al. (1994).

Experimental top

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.

Refinement top

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.

Computing details top

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).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), with atom labels and 30% probability displacement ellipsoids for non-H atoms.
3-O-Ethyl-L-ascorbic acid top
Crystal data top
C8H12O6Dx = 1.449 Mg m3
Mr = 204.18Melting point: 385 K
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 25 reflections
a = 4.6690 (9) Åθ = 10–13°
b = 11.939 (2) ŵ = 0.13 mm1
c = 16.794 (3) ÅT = 293 K
V = 936.2 (3) Å3Plate, colourless
Z = 40.20 × 0.20 × 0.10 mm
F(000) = 432
Data collection top
Enraf–Nonius CAD-4
diffractometer
Rint = 0.028
Radiation source: fine-focus sealed tubeθmax = 25.2°, θmin = 2.1°
Graphite monochromatorh = 05
ω/2θ scansk = 014
1973 measured reflectionsl = 2020
1024 independent reflections3 standard reflections every 200 reflections
882 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.040H 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 reflectionsΔρmax = 0.18 e Å3
137 parametersΔρmin = 0.26 e Å3
1 restraintExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.121 (14)
Crystal data top
C8H12O6V = 936.2 (3) Å3
Mr = 204.18Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 4.6690 (9) ŵ = 0.13 mm1
b = 11.939 (2) ÅT = 293 K
c = 16.794 (3) Å0.20 × 0.20 × 0.10 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
Rint = 0.028
1973 measured reflections3 standard reflections every 200 reflections
1024 independent reflections intensity decay: none
882 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0401 restraint
wR(F2) = 0.138H atoms treated by a mixture of independent and constrained refinement
S = 1.00Δρmax = 0.18 e Å3
1024 reflectionsΔρmin = 0.26 e Å3
137 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.5474 (6)0.5579 (2)0.82156 (13)0.0513 (7)
C10.6281 (17)0.6421 (5)0.9472 (3)0.0896 (18)
H1A0.59960.63521.00360.134*
H1B0.53710.70930.92850.134*
H1C0.82950.64550.93590.134*
O20.1035 (7)0.3667 (2)0.85756 (15)0.0563 (8)
H2A0.027 (12)0.305 (2)0.851 (3)0.084*
C20.5046 (14)0.5463 (4)0.90741 (19)0.0664 (14)
H2B0.30160.54180.91920.080*
H2C0.59530.47820.92620.080*
C30.4076 (7)0.4855 (2)0.77537 (18)0.0385 (8)
O30.0350 (7)0.2854 (2)0.69573 (15)0.0555 (7)
C40.2202 (8)0.4033 (3)0.78834 (19)0.0401 (8)
O40.2730 (6)0.41543 (19)0.65249 (13)0.0451 (7)
C50.1347 (8)0.3595 (3)0.7110 (2)0.0419 (8)
O50.0863 (5)0.64292 (19)0.67658 (15)0.0419 (6)
H5A0.088 (11)0.671 (3)0.727 (3)0.063*
O60.3693 (6)0.7318 (2)0.53918 (14)0.0466 (7)
H6A0.213 (11)0.729 (4)0.511 (3)0.070*
C60.4518 (7)0.4996 (2)0.68745 (17)0.0355 (8)
H6B0.65230.48380.67440.043*
C70.3734 (7)0.6151 (3)0.65672 (17)0.0329 (7)
H7A0.50260.67050.68040.039*
C80.4004 (9)0.6198 (3)0.56722 (18)0.0427 (9)
H8A0.58610.59100.55140.051*
H8B0.25440.57290.54320.051*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0599 (17)0.0583 (14)0.0356 (11)0.0134 (14)0.0067 (13)0.0078 (11)
C10.122 (5)0.091 (3)0.056 (3)0.020 (4)0.007 (3)0.013 (2)
O20.0731 (19)0.0566 (14)0.0391 (12)0.0154 (17)0.0083 (14)0.0088 (12)
C20.096 (4)0.068 (2)0.0350 (16)0.016 (3)0.005 (2)0.0046 (17)
C30.0394 (17)0.0395 (15)0.0365 (15)0.0018 (17)0.0037 (15)0.0049 (13)
O30.0678 (17)0.0441 (13)0.0544 (14)0.0087 (15)0.0043 (15)0.0031 (11)
C40.0452 (19)0.0366 (16)0.0385 (16)0.0016 (15)0.0020 (16)0.0092 (13)
O40.0605 (16)0.0383 (12)0.0364 (11)0.0028 (12)0.0032 (12)0.0020 (9)
C50.0473 (19)0.0352 (15)0.0432 (18)0.0034 (18)0.0011 (17)0.0056 (14)
O50.0367 (13)0.0485 (12)0.0406 (12)0.0064 (12)0.0060 (11)0.0020 (10)
O60.0455 (14)0.0504 (13)0.0440 (13)0.0009 (13)0.0044 (12)0.0163 (11)
C60.0328 (16)0.0358 (15)0.0378 (15)0.0055 (15)0.0032 (14)0.0039 (13)
C70.0293 (15)0.0367 (15)0.0326 (15)0.0029 (14)0.0023 (13)0.0023 (12)
C80.054 (2)0.0394 (16)0.0345 (16)0.0045 (19)0.0078 (17)0.0044 (14)
Geometric parameters (Å, º) top
O1—C31.332 (4)C4—C51.456 (5)
O1—C21.462 (4)O4—C51.353 (4)
C1—C21.444 (7)O4—C61.432 (4)
C1—H1A0.9600O5—C71.421 (4)
C1—H1B0.9600O5—H5A0.91 (4)
C1—H1C0.9600O6—C81.425 (4)
O2—C41.356 (4)O6—H6A0.87 (5)
O2—H2A0.83 (3)C6—C71.516 (4)
C2—H2B0.9700C6—H6B0.9800
C2—H2C0.9700C7—C81.510 (4)
C3—C41.332 (5)C7—H7A0.9800
C3—C61.500 (4)C8—H8A0.9700
O3—C51.215 (4)C8—H8B0.9700
C3—O1—C2116.5 (3)O3—C5—C4129.0 (3)
C2—C1—H1A109.5O4—C5—C4109.9 (3)
C2—C1—H1B109.5C7—O5—H5A107 (3)
H1A—C1—H1B109.5C8—O6—H6A103 (4)
C2—C1—H1C109.5O4—C6—C3104.2 (2)
H1A—C1—H1C109.5O4—C6—C7111.0 (3)
H1B—C1—H1C109.5C3—C6—C7113.8 (3)
C4—O2—H2A110 (4)O4—C6—H6B109.2
C1—C2—O1109.1 (4)C3—C6—H6B109.2
C1—C2—H2B109.9C7—C6—H6B109.2
O1—C2—H2B109.9O5—C7—C8107.7 (3)
C1—C2—H2C109.9O5—C7—C6111.1 (3)
O1—C2—H2C109.9C8—C7—C6110.7 (3)
H2B—C2—H2C108.3O5—C7—H7A109.1
O1—C3—C4134.8 (3)C8—C7—H7A109.1
O1—C3—C6115.7 (3)C6—C7—H7A109.1
C4—C3—C6109.5 (3)O6—C8—C7110.8 (3)
C3—C4—O2129.9 (3)O6—C8—H8A109.5
C3—C4—C5107.4 (3)C7—C8—H8A109.5
O2—C4—C5122.6 (3)O6—C8—H8B109.5
C5—O4—C6109.1 (2)C7—C8—H8B109.5
O3—C5—O4121.1 (3)H8A—C8—H8B108.1
C3—O1—C2—C1169.9 (4)C5—O4—C6—C31.1 (3)
C2—O1—C3—C43.1 (6)C5—O4—C6—C7121.7 (3)
C2—O1—C3—C6179.3 (3)O1—C3—C6—O4178.1 (3)
O1—C3—C4—O21.1 (6)C4—C3—C6—O40.9 (4)
C6—C3—C4—O2175.3 (3)O1—C3—C6—C757.1 (4)
O1—C3—C4—C5176.8 (4)C4—C3—C6—C7120.0 (3)
C6—C3—C4—C50.4 (4)O4—C6—C7—O561.3 (3)
C6—O4—C5—O3178.3 (3)C3—C6—C7—O555.8 (4)
C6—O4—C5—C41.0 (4)O4—C6—C7—C858.3 (4)
C3—C4—C5—O3178.9 (4)C3—C6—C7—C8175.4 (3)
O2—C4—C5—O32.8 (6)O5—C7—C8—O667.1 (4)
C3—C4—C5—O40.3 (4)C6—C7—C8—O6171.2 (3)
O2—C4—C5—O4176.4 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2A···O5i0.83 (3)2.06 (3)2.873 (3)168 (5)
O5—H5A···O3ii0.91 (5)1.90 (4)2.748 (4)154 (4)
O6—H6A···O6iii0.87 (5)1.87 (5)2.715 (4)163 (4)
Symmetry codes: (i) x, y1/2, z+3/2; (ii) x, y+1/2, z+3/2; (iii) x1/2, y+3/2, z+1.

Experimental details

Crystal data
Chemical formulaC8H12O6
Mr204.18
Crystal system, space groupOrthorhombic, P212121
Temperature (K)293
a, b, c (Å)4.6690 (9), 11.939 (2), 16.794 (3)
V3)936.2 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.13
Crystal size (mm)0.20 × 0.20 × 0.10
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
1973, 1024, 882
Rint0.028
(sin θ/λ)max1)0.600
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.138, 1.00
No. of reflections1024
No. of parameters137
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.18, 0.26

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2A···O5i0.83 (3)2.06 (3)2.873 (3)168 (5)
O5—H5A···O3ii0.91 (5)1.90 (4)2.748 (4)154 (4)
O6—H6A···O6iii0.87 (5)1.87 (5)2.715 (4)163 (4)
Symmetry codes: (i) x, y1/2, z+3/2; (ii) x, y+1/2, z+3/2; (iii) x1/2, y+3/2, z+1.
 

References

First citationEnraf–Nonius (1989). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands.  Google Scholar
First citationHarms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.  Google Scholar
First citationNihro, Y., Sogawa, S. & Izumi, A. (1992). J. Med. Chem. 35, 1618–1623.  CrossRef PubMed CAS Web of Science Google Scholar
First citationSatoh, T., Niino, Y. & Matsumoto, H. (1994). Jpn Patent JP6228557.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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ISSN: 2056-9890
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