organic compounds
1,2,3-Tri-O-acetyl-5-deoxy-D-ribofuranose
aSchool of Pharmacy, Anhui Medical University, Hefei 230032, People's Republic of China
*Correspondence e-mail: ahmupharm@126.com
The title compound, C11H16O7, was obtained from the breakage reaction of the glycosidic bond of 5′-deoxy-2′,3′-diacetylinosine. The ribofuranose ring has a C2-exo, C3-endo twist configuration. No alteration of the compared with D-(−)-ribose is observed.
Related literature
For possible catalytic mechanisms at the anomeric carbon centre in the cleavage of glycosidic linkages, see: Vocadlo et al. (2001). For the synthesis of the title compound from D-ribose, see: Sairam et al. (2003). For a 5-deoxy-ribofuranoid active as an antitumour drug, see: Shimma et al. (2000).
Experimental
Crystal data
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Data collection: SMART (Siemens, 1996); cell SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S160053681004482X/si2303sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053681004482X/si2303Isup2.hkl
The title compound was prepared from the reaction of the breakage of the glycosidic bond of 5'-Deoxy-2',3'-diacetyl-inosine, which was gained from inosine by halogenation, hydrogenization and acetylation in turn. 5'-Deoxy-2',3'-diacetyl-inosine (6.72 g, 20 mmol) and cation-exchange resin (6 g) were added to a solution of acetic anhydride/acetic acid (60 ml, 9: 1), was heated to 358 K and reacted under stirring for 8 h. The reacting mixture was filtered and the filtrate was concentrated in vacuo. The residue was resolved in ethyl acetate, then the precipitate was filtered and the filtrate was washed by the
of NaHCO3. The organic layer was dried with anhydrous Na2SO4, filtered, and concentrated in vacuo. The residue was recrystallized from methanol/water. The purified title compound was subsequently dissolved in methanol and added water to the solution until it turned cloudy. Upon standing at room temperature, a colorless block appeared and was separated from the solvent by decantation.All H atoms were positioned geometrically and refined using a riding model, with C—H distances of 0.98 Å (methyl), with Uiso(H) = 1.2Ueq(C) and 1.5Ueq(C-methyl).
In the absence of significant
effects, Friedel pairs were averaged.During the last decades there has been considerable interest in the chemical synthesis of the nucleoside analogues for their biological evaluation of the anti-tumor activity (Sairam et al., 2003). 1,2,3-O-Triacetyl-5-deoxy-D-ribofuranose, as one of the important intermediates, was used to synthesize some anti-cancer drugs such as Doxifluridine, Capecitabine (Shimma et al., 2000), and so on. There were different synthetic routes available in literature for the synthesis of this intermediate. We obtained this compound from inosine as starting material in a linear synthetic route. Possible formation mechanisms of the title compound are shown in Fig. 1. To know the relative stereochemistry of the anomeric position in the ribose, it is therefore necessary to gain the well defined structure of the 1,2,3-O-triacetyl-5-deoxy-D-ribofuranose by X-diffraction method (Fig. 2).
We observed that the ribofuranose ring has a C2-exo, C3-endo twist configuration and the anomeric carbons are always β configuration in the crystal packing. We suppose that the mechanism of the breakage reaction of the glycosidic bond is similar to that of the glycoside hydrolase (Vocadlo et al., 2001). Firstly, the nucleophilic group of the cation resin attacks the anomeric centre of the 5'-deoxy-2',3'-diacetyl-inosine, resulting in the formation of a glycosyl intermediate. Then a nucleophilic acetic anhydride as a base acts the glycosyl intermediate by acetolysis, giving the title product. In another way, the product obtained with sulfuric acid as catalyst is a α/β anomeric mixture and the yield is much lower. This difference may be because the intermediate produced using strong acid is a carbocation and the furan ring may be decomposed to some byproducts.
For possible catalytic mechanisms at the anomeric carbon centre in the cleavage of glycosidic linkages, see: Vocadlo et al. (2001). For the synthesis of the title compound from D-ribose, see: Sairam et al. (2003). For a 5-deoxy-ribofuranoid active as an antitumour drug, see: Shimma et al. (2000).
Data collection: SMART (Siemens, 1996); cell
SAINT (Siemens, 1996); data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).Fig. 1. Possible formation mechanisms of the title compound. | |
Fig. 2. ORTEP drawing of the title compound with atomic numbering scheme and thermal ellipsoids at 30% probability level. |
C11H16O7 | Dx = 1.309 Mg m−3 |
Mr = 260.24 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 1390 reflections |
a = 7.592 (2) Å | θ = 2.6–21.6° |
b = 8.505 (2) Å | µ = 0.11 mm−1 |
c = 20.445 (2) Å | T = 298 K |
V = 1320.1 (5) Å3 | Prism, colourless |
Z = 4 | 0.48 × 0.45 × 0.32 mm |
F(000) = 552 |
Siemens SMART 1000 CCD area-detector diffractometer | 1368 independent reflections |
Radiation source: fine-focus sealed tube | 848 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.036 |
φ and ω scans | θmax = 25.0°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −9→8 |
Tmin = 0.949, Tmax = 0.966 | k = −10→9 |
5470 measured reflections | l = −24→11 |
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)] = 0.041 | H-atom parameters constrained |
wR(F2) = 0.133 | w = 1/[σ2(Fo2) + (0.0609P)2 + 0.2525P] where P = (Fo2 + 2Fc2)/3 |
S = 1.04 | (Δ/σ)max < 0.001 |
1368 reflections | Δρmax = 0.18 e Å−3 |
168 parameters | Δρmin = −0.13 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.022 (4) |
C11H16O7 | V = 1320.1 (5) Å3 |
Mr = 260.24 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 7.592 (2) Å | µ = 0.11 mm−1 |
b = 8.505 (2) Å | T = 298 K |
c = 20.445 (2) Å | 0.48 × 0.45 × 0.32 mm |
Siemens SMART 1000 CCD area-detector diffractometer | 1368 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 848 reflections with I > 2σ(I) |
Tmin = 0.949, Tmax = 0.966 | Rint = 0.036 |
5470 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 0 restraints |
wR(F2) = 0.133 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.18 e Å−3 |
1368 reflections | Δρmin = −0.13 e Å−3 |
168 parameters |
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. |
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 | 0.1176 (4) | 0.2987 (4) | 0.07061 (14) | 0.0875 (10) | |
O2 | 0.2931 (4) | 0.3413 (4) | 0.16197 (14) | 0.0848 (10) | |
O3 | 0.4083 (8) | 0.5348 (6) | 0.1051 (2) | 0.162 (2) | |
O4 | 0.2959 (4) | −0.0158 (4) | 0.07017 (13) | 0.0873 (11) | |
O5 | 0.5372 (5) | −0.0822 (5) | 0.1230 (2) | 0.1261 (16) | |
O6 | −0.0276 (4) | −0.0744 (3) | 0.12588 (12) | 0.0711 (9) | |
O7 | 0.0619 (5) | −0.1341 (4) | 0.22641 (13) | 0.0952 (12) | |
C1 | 0.2710 (6) | 0.2524 (6) | 0.1032 (2) | 0.0750 (13) | |
H1 | 0.3742 | 0.2633 | 0.0748 | 0.090* | |
C2 | 0.2469 (6) | 0.0844 (6) | 0.12401 (18) | 0.0695 (12) | |
H2 | 0.3104 | 0.0591 | 0.1644 | 0.083* | |
C3 | 0.0506 (6) | 0.0772 (5) | 0.13214 (17) | 0.0628 (11) | |
H3 | 0.0192 | 0.1214 | 0.1748 | 0.075* | |
C4 | −0.0187 (6) | 0.1839 (5) | 0.07907 (19) | 0.0678 (11) | |
H4 | −0.0317 | 0.1235 | 0.0385 | 0.081* | |
C5 | −0.1893 (6) | 0.2655 (5) | 0.0940 (2) | 0.0917 (16) | |
H5A | −0.1762 | 0.3274 | 0.1330 | 0.138* | |
H5B | −0.2802 | 0.1886 | 0.1005 | 0.138* | |
H5C | −0.2206 | 0.3327 | 0.0581 | 0.138* | |
C6 | 0.3685 (7) | 0.4813 (7) | 0.1569 (3) | 0.0917 (15) | |
C7 | 0.3865 (8) | 0.5618 (7) | 0.2211 (3) | 0.1153 (19) | |
H7A | 0.4613 | 0.5007 | 0.2492 | 0.173* | |
H7B | 0.2725 | 0.5726 | 0.2409 | 0.173* | |
H7C | 0.4374 | 0.6639 | 0.2146 | 0.173* | |
C8 | 0.4508 (7) | −0.0888 (6) | 0.0750 (2) | 0.0784 (13) | |
C9 | 0.4968 (8) | −0.1728 (7) | 0.0142 (2) | 0.111 (2) | |
H9A | 0.5860 | −0.1152 | −0.0088 | 0.166* | |
H9B | 0.3940 | −0.1822 | −0.0128 | 0.166* | |
H9C | 0.5403 | −0.2757 | 0.0248 | 0.166* | |
C10 | −0.0159 (6) | −0.1698 (5) | 0.1781 (2) | 0.0681 (11) | |
C11 | −0.1095 (8) | −0.3204 (6) | 0.1666 (2) | 0.0968 (16) | |
H11A | −0.0379 | −0.3877 | 0.1399 | 0.145* | |
H11B | −0.2191 | −0.3001 | 0.1448 | 0.145* | |
H11C | −0.1320 | −0.3709 | 0.2078 | 0.145* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.090 (2) | 0.087 (2) | 0.086 (2) | −0.018 (2) | −0.0159 (18) | 0.0309 (18) |
O2 | 0.095 (2) | 0.089 (2) | 0.0703 (19) | −0.023 (2) | −0.0001 (17) | 0.0068 (19) |
O3 | 0.232 (6) | 0.137 (4) | 0.116 (3) | −0.093 (4) | 0.011 (4) | 0.022 (3) |
O4 | 0.087 (2) | 0.115 (3) | 0.0599 (17) | 0.025 (2) | −0.0058 (16) | −0.0044 (18) |
O5 | 0.099 (3) | 0.135 (4) | 0.145 (3) | 0.029 (3) | −0.043 (3) | −0.031 (3) |
O6 | 0.098 (2) | 0.0548 (17) | 0.0604 (16) | −0.0068 (19) | −0.0069 (15) | 0.0085 (14) |
O7 | 0.148 (3) | 0.079 (2) | 0.0585 (17) | −0.009 (2) | −0.0165 (19) | 0.0096 (16) |
C1 | 0.070 (3) | 0.095 (4) | 0.060 (2) | −0.010 (3) | 0.000 (2) | 0.004 (2) |
C2 | 0.073 (3) | 0.088 (3) | 0.048 (2) | 0.006 (3) | −0.006 (2) | 0.001 (2) |
C3 | 0.077 (3) | 0.062 (3) | 0.050 (2) | 0.001 (3) | −0.0017 (19) | 0.010 (2) |
C4 | 0.077 (3) | 0.064 (2) | 0.062 (2) | −0.008 (3) | −0.012 (2) | 0.010 (2) |
C5 | 0.081 (3) | 0.074 (3) | 0.120 (4) | 0.003 (3) | −0.013 (3) | 0.016 (3) |
C6 | 0.100 (4) | 0.086 (4) | 0.089 (4) | −0.024 (3) | −0.009 (3) | 0.015 (3) |
C7 | 0.132 (5) | 0.101 (4) | 0.112 (4) | −0.019 (4) | −0.028 (4) | −0.003 (4) |
C8 | 0.073 (3) | 0.076 (3) | 0.086 (3) | −0.002 (3) | 0.005 (3) | 0.007 (3) |
C9 | 0.118 (4) | 0.113 (4) | 0.102 (4) | 0.007 (4) | 0.030 (3) | 0.008 (4) |
C10 | 0.086 (3) | 0.062 (3) | 0.057 (2) | 0.009 (3) | 0.006 (2) | 0.011 (2) |
C11 | 0.135 (4) | 0.067 (3) | 0.088 (3) | −0.015 (3) | −0.014 (3) | 0.018 (3) |
O1—C1 | 1.399 (5) | C4—C5 | 1.501 (6) |
O1—C4 | 1.433 (5) | C4—H4 | 0.9800 |
O2—C6 | 1.325 (6) | C5—H5A | 0.9600 |
O2—C1 | 1.429 (5) | C5—H5B | 0.9600 |
O3—C6 | 1.192 (6) | C5—H5C | 0.9600 |
O4—C8 | 1.333 (6) | C6—C7 | 1.485 (7) |
O4—C2 | 1.441 (5) | C7—H7A | 0.9600 |
O5—C8 | 1.183 (6) | C7—H7B | 0.9600 |
O6—C10 | 1.344 (4) | C7—H7C | 0.9600 |
O6—C3 | 1.425 (5) | C8—C9 | 1.475 (6) |
O7—C10 | 1.190 (5) | C9—H9A | 0.9600 |
C1—C2 | 1.502 (6) | C9—H9B | 0.9600 |
C1—H1 | 0.9800 | C9—H9C | 0.9600 |
C2—C3 | 1.500 (6) | C10—C11 | 1.484 (6) |
C2—H2 | 0.9800 | C11—H11A | 0.9600 |
C3—C4 | 1.509 (5) | C11—H11B | 0.9600 |
C3—H3 | 0.9800 | C11—H11C | 0.9600 |
C1—O1—C4 | 110.6 (3) | C4—C5—H5C | 109.5 |
C6—O2—C1 | 117.4 (4) | H5A—C5—H5C | 109.5 |
C8—O4—C2 | 116.5 (3) | H5B—C5—H5C | 109.5 |
C10—O6—C3 | 116.6 (3) | O3—C6—O2 | 121.4 (5) |
O1—C1—O2 | 110.4 (4) | O3—C6—C7 | 125.8 (5) |
O1—C1—C2 | 107.5 (4) | O2—C6—C7 | 112.7 (5) |
O2—C1—C2 | 106.3 (3) | C6—C7—H7A | 109.5 |
O1—C1—H1 | 110.8 | C6—C7—H7B | 109.5 |
O2—C1—H1 | 110.8 | H7A—C7—H7B | 109.5 |
C2—C1—H1 | 110.8 | C6—C7—H7C | 109.5 |
O4—C2—C1 | 108.4 (3) | H7A—C7—H7C | 109.5 |
O4—C2—C3 | 108.5 (4) | H7B—C7—H7C | 109.5 |
C1—C2—C3 | 101.0 (4) | O5—C8—O4 | 121.9 (5) |
O4—C2—H2 | 112.7 | O5—C8—C9 | 126.3 (5) |
C1—C2—H2 | 112.7 | O4—C8—C9 | 111.8 (5) |
C3—C2—H2 | 112.7 | C8—C9—H9A | 109.5 |
O6—C3—C2 | 116.1 (4) | C8—C9—H9B | 109.5 |
O6—C3—C4 | 109.5 (3) | H9A—C9—H9B | 109.5 |
C2—C3—C4 | 104.0 (3) | C8—C9—H9C | 109.5 |
O6—C3—H3 | 109.0 | H9A—C9—H9C | 109.5 |
C2—C3—H3 | 109.0 | H9B—C9—H9C | 109.5 |
C4—C3—H3 | 109.0 | O7—C10—O6 | 122.6 (4) |
O1—C4—C5 | 109.4 (4) | O7—C10—C11 | 126.1 (4) |
O1—C4—C3 | 104.1 (3) | O6—C10—C11 | 111.4 (4) |
C5—C4—C3 | 115.6 (4) | C10—C11—H11A | 109.5 |
O1—C4—H4 | 109.1 | C10—C11—H11B | 109.5 |
C5—C4—H4 | 109.1 | H11A—C11—H11B | 109.5 |
C3—C4—H4 | 109.1 | C10—C11—H11C | 109.5 |
C4—C5—H5A | 109.5 | H11A—C11—H11C | 109.5 |
C4—C5—H5B | 109.5 | H11B—C11—H11C | 109.5 |
H5A—C5—H5B | 109.5 |
Experimental details
Crystal data | |
Chemical formula | C11H16O7 |
Mr | 260.24 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 298 |
a, b, c (Å) | 7.592 (2), 8.505 (2), 20.445 (2) |
V (Å3) | 1320.1 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.48 × 0.45 × 0.32 |
Data collection | |
Diffractometer | Siemens SMART 1000 CCD area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.949, 0.966 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5470, 1368, 848 |
Rint | 0.036 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.133, 1.04 |
No. of reflections | 1368 |
No. of parameters | 168 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.18, −0.13 |
Computer programs: SMART (Siemens, 1996), SAINT (Siemens, 1996), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
Acknowledgements
This work was supported by the National Natural Science Foundation of China (grant No. 20802003) and the Scientific Research Fund of Anhui Provincial Education Department (grant No. KJ2008B171)
References
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Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Shimma, N., Umeda, I., Arasaki, M., Murasaki, C., Masubuchi, K., Kohchi, Y., Miwa, M., Ura, M., Sawada, N., Tahara, H., Kuruma, I., Horii, I. & Ishitsuka, H. (2000). Bioorg. Med. Chem. 8, 1697–1706. Web of Science CrossRef PubMed CAS Google Scholar
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During the last decades there has been considerable interest in the chemical synthesis of the nucleoside analogues for their biological evaluation of the anti-tumor activity (Sairam et al., 2003). 1,2,3-O-Triacetyl-5-deoxy-D-ribofuranose, as one of the important intermediates, was used to synthesize some anti-cancer drugs such as Doxifluridine, Capecitabine (Shimma et al., 2000), and so on. There were different synthetic routes available in literature for the synthesis of this intermediate. We obtained this compound from inosine as starting material in a linear synthetic route. Possible formation mechanisms of the title compound are shown in Fig. 1. To know the relative stereochemistry of the anomeric position in the ribose, it is therefore necessary to gain the well defined structure of the 1,2,3-O-triacetyl-5-deoxy-D-ribofuranose by X-diffraction method (Fig. 2).
We observed that the ribofuranose ring has a C2-exo, C3-endo twist configuration and the anomeric carbons are always β configuration in the crystal packing. We suppose that the mechanism of the breakage reaction of the glycosidic bond is similar to that of the glycoside hydrolase (Vocadlo et al., 2001). Firstly, the nucleophilic group of the cation resin attacks the anomeric centre of the 5'-deoxy-2',3'-diacetyl-inosine, resulting in the formation of a glycosyl intermediate. Then a nucleophilic acetic anhydride as a base acts the glycosyl intermediate by acetolysis, giving the title product. In another way, the product obtained with sulfuric acid as catalyst is a α/β anomeric mixture and the yield is much lower. This difference may be because the intermediate produced using strong acid is a carbocation and the furan ring may be decomposed to some byproducts.