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Kinfe, Henok H.

Makolo, Felix L.

Muller, Alfred

Phasha, Zanele

English

University of Johannesburg Institutional Repository

3,4,6-Tri-O-acetyl-1,2-[(S)-ethylidene]-b-D-mannopyranoseHenok H. Kinfe, Felix L. Makolo, Zanele Phasha andAlfred Muller*Research Center for Synthesis and Catalysis, Department of Chemistry, University ofJohannesburg (APK Campus), PO Box 524, Auckland Park, Johannesburg, 2006,South AfricaCorrespondence e-mail: mullera@uj.ac.zaReceived 5 July 2012; accepted 16 July 2012Key indicators: single-crystal X-ray study; T = 100 K; mean (C–C) = 0.002 A˚;R factor = 0.026; wR factor = 0.085; data-to-parameter ratio = 12.7.In the title compound, C14H20O9, the six-membered pyran andthe five-membered dioxalane rings adopt chair and twistedconformations, respectively. In the crystal, the molecules arelinked by C—H  O interactions.Related literatureFor orthogonal protection in carbohydrate chemistry, see:Wuts & Greene (2007); Betaneli et al. (1982). For backgroundto the synthetic methodology, see: Doores et al. (2010). Forring puckering analysis, see: Cremer & Pople (1975).ExperimentalCrystal dataC14H20O9Mr = 332.3Orthorhombic, P212121a = 7.0494 (3) A˚b = 14.6994 (7) A˚c = 15.3608 (7) A˚V = 1591.72 (12) A˚3Z = 4Cu K radiation = 1.01 mm1T = 100 K0.16  0.16  0.12 mmData collectionBruker APEX DUO 4K-CCDdiffractometerAbsorption correction: multi-scan(SADABS; Bruker, 2008)Tmin = 0.856, Tmax = 0.88923454 measured reflections2701 independent reflections2684 reflections with I > 2(I)Rint = 0.028RefinementR[F 2 > 2(F 2)] = 0.026wR(F 2) = 0.085S = 1.202701 reflections212 parametersH-atom parameters constrainedmax = 0.26 e A˚3min = 0.31 e A˚3Absolute structure: Flack (1983),1110 Friedel PairsFlack parameter: 0.06 (15)Table 1Hydrogen-bond geometry (A˚, ).D—H  A D—H H  A D  A D—H  AC1—H1C  O3i 0.98 2.55 3.511 (2) 167C8—H8  O7i 1.00 2.49 3.317 (2) 140C12—H12A  O4ii 0.98 2.56 3.469 (2) 154C12—H12B  O1iii 0.98 2.51 3.460 (2) 163C14—H14B  O9iv 0.98 2.53 3.361 (2) 142Symmetry codes: (i) xþ 1; y 12;z þ 12; (ii) xþ 32;yþ 2; zþ 12; (iii)x þ 1; yþ 12;zþ 12; (iv) x 12;yþ 32;zþ 1.Data collection: APEX2 (Bruker, 2011); cell refinement: SAINT(Bruker, 2008); data reduction: SAINT and XPREP (Bruker, 2008);program(s) used to solve structure: SHELXS97 (Sheldrick, 2008);program(s) used to refine structure: SHELXL97 (Sheldrick, 2008);molecular graphics: DIAMOND (Brandenburg & Putz, 2005); soft-ware used to prepare material for publication: WinGX (Farrugia,1999).Research funds of the University of Johannesburg and theResearch Center for Synthesis and Catalysis are gratefullyacknowledged.Supplementary data and figures for this paper are available from theIUCr electronic archives (Reference: XU5592).ReferencesBetaneli, V. I., Ovchinnikov, M. V., Bakinovskii, L. V. & Kochetkov, N. K.(1982). Carbohydr. Res. 107, 285–291.Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn,Germany.Bruker (2008). SADABS, SAINT and XPREP. BrukerAXS Inc., Madison,Wisconsin, USA.Bruker (2011). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358.Doores, K. J., Fulton, Z., Hong, V., Patel, M. K., Scanlan, C. N., Wormald, M.R., Finn, M. G., Burton, D. R., Wilson, I. A. & Davis, B. G. (2010). Proc. NatlAcad. Sci. USA, 102, 13372–13377.Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.Flack, H. D. (1983). Acta Cryst. A39, 876–881.Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.Wuts, P. G. W. & Greene, T. W. (2007). Protective Groups in Organic Synthesis,4th ed. New Jersey: Wiley.organic compoundso2520 Kinfe et al. doi:10.1107/S1600536812032369 Acta Cryst. (2012). E68, o2520Acta Crystallographica Section EStructure ReportsOnlineISSN 1600-5368supplementary materialssup-1Acta Cryst. (2012). E68, o2520    supplementary materialsActa Cryst. (2012). E68, o2520    [doi:10.1107/S1600536812032369]3,4,6-Tri-O-acetyl-1,2-[(S)-ethylidene]-β-D-mannopyranoseHenok H. Kinfe, Felix L. Makolo, Zanele Phasha and Alfred MullerComment Ethylidene acetals are important functional groups for orthogonal protection in carbohydrate chemistry (Wuts & Greene, 2007; Betaneli et al., 1982). The title compound is a key intermediate for the preparation of polysaccharides which exhibit strong activity against the HIV-1 virus (Doores et al., 2010). Herein, we report the crystal structure of 3,4,6-tri-O-acetyl-1,2-O-[S-ethylidene] -β-D-mannopyranoside to confirm its absolute configuration.The title compound C14H20O9 (see Fig. 1, and Scheme 1) crystallizes in the P212121 (Z = 4) space group. Puckering analysis confirms the twisted conformation of the five membered dioxalane ring, with puckering parameter values of q2 = 0.347 (3) Å, and φ2 = 61.9 (4)°; and that of the six membered pyran chair conformation ring as q2 = 0.163 (3) Å, q3 = -0.526 (3) Å, Q = 0.550 (3) Å and φ2 = 253.3 (9)° (see Cremer & Pople, 1975). The dioxalane ring is twisted on C6–C7.The molecules are linked by C-H···O interactions (see Table 1).Experimental A solution of 2,3,4,6-tetra-O-acetyl -α-D-mannopyranosyl bromide (150 mg, 0.36 mmol) in acetonitrile (3 ml) was treated with sodium boron hydride (250 mg, 6.61 mmol) and the reaction mixture was stirred at room temperature for 12 h. The mixture was then diluted with chloroform and washed with water three times. The organic layer was dried over anhydrous Na2SO4, filtered and evaporated in vacuo to give an oil. The oily residue was crashed with methanol to afford 70% of the target compound as white crystals.Analytical data: mp: 108-110 °C (Lit. 113-115 °C; Betaneli et al., 1982); 1H NMR (CDCl3, 400 MHz): δ 5.40-5.10 (m, 4H), 4.31-4.03 (m, 3H), 3.72-3.64 (m, 1H), 2.09 (s, 3H), 2.04 (s, 3H), 2.02 (s, 3H), 1.51 (d, J = 4.8 Hz, 3H); 13C NMR (CDCl3, 400 MHz): δ 170.7, 170.3, 169.5, 104.8, 96.5, 71.6, 70.6, 66.0, 62.5, 21.6, 20.7, 20.7.Refinement All hydrogen atoms were positioned in geometrically idealized positions with C–H = 1.00 Å (methine), 0.99 Å (methyl-ene), and 0.98 Å (methyl). All hydrogen atoms were allowed to ride on their parent atoms with Uiso(H) = 1.2Ueq, except for the methyl where Uiso(H) = 1.5Ueq was utilized. The initial positions of methyl hydrogen atoms were located from a Fourier difference map and refined as a fixed rotor. The D enantiomer refined to a final Flack parameter of 0.06 (15). The highest residual electron density of 0.50 e.Å-3 is 0.93 Å from H14B.Computing details Data collection: APEX2 (Bruker, 2011); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT and XPREP (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).supplementary materialssup-2Acta Cryst. (2012). E68, o2520    Figure 1A view of (1). Displacement ellipsoids are drawn at the 50% probability level. 3,4,6-Tri-O-acetyl-1,2-[(S)-ethylidene]-β-D- mannopyranose Crystal data C14H20O9Mr = 332.3Orthorhombic, P212121Hall symbol: P 2ac 2aba = 7.0494 (3) Åb = 14.6994 (7) Åc = 15.3608 (7) ÅV = 1591.72 (12) Å3Z = 4F(000) = 704Dx = 1.387 Mg m−3Cu Kα radiation, λ = 1.54178 ÅCell parameters from 9727 reflectionsθ = 6.5–65.8°µ = 1.01 mm−1T = 100 KCube, colourless0.16 × 0.16 × 0.12 mmData collection Bruker APEX DUO 4K-CCD diffractometerRadiation source: Incoatec IµS microfocus X-ray sourceIncoatec Quazar Multilayer Mirror monochromatorDetector resolution: 8.4 pixels mm-1φ and ω scansAbsorption correction: multi-scan (SADABS; Bruker, 2008)Tmin = 0.856, Tmax = 0.88923454 measured reflections2701 independent reflections2684 reflections with I > 2σ(I)supplementary materialssup-3Acta Cryst. (2012). E68, o2520    Rint = 0.028θmax = 66.2°, θmin = 4.2°h = −8→8k = −16→14l = −18→17Refinement Refinement on F2Least-squares matrix: fullR[F2 > 2σ(F2)] = 0.026wR(F2) = 0.085S = 1.202701 reflections212 parameters0 restraintsPrimary atom site location: structure-invariant direct methodsSecondary atom site location: difference Fourier mapHydrogen site location: inferred from neighbouring sitesH-atom parameters constrainedw = 1/[σ2(Fo2) + (0.0494P)2 + 0.3436P] where P = (Fo2 + 2Fc2)/3(Δ/σ)max = 0.001Δρmax = 0.26 e Å−3Δρmin = −0.31 e Å−3Absolute structure: Flack (1983), 1110 Friedel PairsFlack parameter: 0.06 (15)Special details Experimental. The intensity data was collected on a Bruker Apex DUO 4 K CCD diffractometer using an exposure time of 5 s/frame. A total of 4548 frames were collected with a frame width of 1° covering up to θ = 66.21° with 97.7% completeness accomplished.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) x y z Uiso*/UeqC1 0.1916 (3) 0.55884 (11) 0.36854 (11) 0.0238 (4)H1A 0.0905 0.5131 0.3687 0.036*H1B 0.2086 0.5828 0.4276 0.036*H1C 0.3102 0.5309 0.3487 0.036*C2 0.1392 (2) 0.63445 (10) 0.30873 (10) 0.0191 (3)C3 0.2253 (2) 0.78379 (10) 0.26420 (10) 0.0182 (3)H3 0.085 0.7938 0.2623 0.022*C4 0.3175 (2) 0.86302 (10) 0.30997 (10) 0.0181 (3)H4 0.4551 0.8504 0.3202 0.022*C5 0.2937 (2) 0.94827 (11) 0.25454 (10) 0.0199 (3)H5 0.156 0.9571 0.2413 0.024*C6 0.3204 (2) 0.86280 (11) 0.12195 (10) 0.0200 (3)H6 0.1988 0.8811 0.0933 0.024*C7 0.2989 (2) 0.77323 (10) 0.17178 (10) 0.0195 (3)H7 0.2167 0.7302 0.1384 0.023*C8 0.5782 (3) 0.76982 (12) 0.09524 (12) 0.0275 (4)H8 0.5843 0.7181 0.053 0.033*C9 0.7739 (3) 0.80202 (14) 0.11606 (13) 0.0346 (4)supplementary materialssup-4Acta Cryst. (2012). E68, o2520    H9A 0.7676 0.8491 0.1611 0.052*H9B 0.8325 0.8273 0.0635 0.052*H9C 0.85 0.7508 0.1372 0.052*C10 0.3704 (2) 1.03347 (11) 0.29613 (11) 0.0214 (4)H10A 0.3591 1.0852 0.2552 0.026*H10B 0.2967 1.048 0.3492 0.026*C11 0.6193 (2) 1.03193 (10) 0.40213 (11) 0.0203 (4)C12 0.8252 (3) 1.01153 (13) 0.41372 (11) 0.0258 (4)H12A 0.8696 1.038 0.4686 0.039*H12B 0.8971 1.0378 0.3652 0.039*H12C 0.8441 0.9455 0.4149 0.039*C13 0.3177 (2) 0.85697 (10) 0.46588 (11) 0.0208 (3)C14 0.1957 (3) 0.87231 (12) 0.54383 (11) 0.0274 (4)H14A 0.267 0.857 0.5966 0.041*H14B 0.0827 0.8337 0.54 0.041*H14C 0.1573 0.9363 0.5461 0.041*O1 0.00432 (18) 0.63631 (8) 0.26050 (8) 0.0251 (3)O2 0.26442 (16) 0.70374 (7) 0.31509 (7) 0.0192 (2)O3 0.39448 (16) 0.93390 (8) 0.17474 (8) 0.0213 (3)O4 0.46022 (18) 0.84164 (8) 0.06055 (8) 0.0251 (3)O5 0.48923 (17) 0.74080 (7) 0.17374 (8) 0.0234 (3)O6 0.56740 (16) 1.01897 (7) 0.31844 (7) 0.0202 (3)O7 0.51158 (18) 1.05559 (8) 0.45868 (8) 0.0249 (3)O8 0.22067 (16) 0.87679 (7) 0.39160 (7) 0.0201 (3)O9 0.47936 (18) 0.83119 (8) 0.46649 (8) 0.0265 (3)Atomic displacement parameters (Å2) U11 U22 U33 U12 U13 U23C1 0.0263 (9) 0.0187 (8) 0.0263 (8) −0.0010 (7) 0.0026 (7) 0.0042 (7)C2 0.0200 (8) 0.0172 (8) 0.0200 (8) −0.0019 (6) 0.0034 (7) −0.0019 (6)C3 0.0178 (7) 0.0158 (7) 0.0210 (7) −0.0010 (6) −0.0022 (6) 0.0033 (6)C4 0.0179 (7) 0.0177 (8) 0.0186 (7) 0.0006 (6) 0.0005 (6) 0.0012 (6)C5 0.0192 (7) 0.0181 (8) 0.0224 (8) 0.0014 (6) −0.0036 (6) 0.0007 (6)C6 0.0210 (8) 0.0197 (8) 0.0192 (8) −0.0022 (6) −0.0015 (6) 0.0008 (6)C7 0.0197 (8) 0.0170 (7) 0.0216 (7) 0.0000 (6) −0.0008 (7) 0.0005 (6)C8 0.0314 (9) 0.0222 (8) 0.0290 (9) 0.0041 (7) 0.0065 (8) 0.0050 (7)C9 0.0309 (10) 0.0329 (10) 0.0399 (10) 0.0006 (8) 0.0032 (8) 0.0091 (8)C10 0.0198 (8) 0.0186 (8) 0.0259 (8) 0.0014 (6) −0.0065 (7) 0.0008 (7)C11 0.0275 (9) 0.0128 (7) 0.0207 (8) −0.0017 (7) −0.0031 (7) 0.0031 (7)C12 0.0243 (9) 0.0293 (9) 0.0238 (8) −0.0009 (7) −0.0044 (7) 0.0016 (7)C13 0.0247 (9) 0.0147 (8) 0.0229 (8) −0.0006 (6) −0.0043 (7) −0.0007 (6)C14 0.0315 (9) 0.0283 (9) 0.0222 (8) 0.0003 (8) −0.0005 (7) −0.0040 (7)O1 0.0234 (6) 0.0225 (6) 0.0294 (6) −0.0049 (5) −0.0047 (5) 0.0021 (5)O2 0.0208 (6) 0.0158 (5) 0.0210 (5) −0.0030 (4) −0.0030 (4) 0.0039 (4)O3 0.0246 (6) 0.0186 (5) 0.0208 (5) −0.0046 (5) −0.0017 (5) 0.0019 (5)O4 0.0271 (6) 0.0229 (6) 0.0254 (6) 0.0029 (5) 0.0053 (5) 0.0057 (5)O5 0.0241 (6) 0.0202 (5) 0.0259 (6) 0.0051 (5) 0.0051 (5) 0.0060 (5)O6 0.0199 (6) 0.0203 (5) 0.0204 (5) −0.0003 (4) −0.0039 (5) −0.0014 (5)O7 0.0286 (6) 0.0242 (6) 0.0219 (6) 0.0031 (5) 0.0011 (5) −0.0005 (5)supplementary materialssup-5Acta Cryst. (2012). E68, o2520    O8 0.0200 (6) 0.0218 (5) 0.0186 (5) 0.0022 (5) −0.0007 (5) −0.0005 (4)O9 0.0257 (7) 0.0287 (6) 0.0250 (6) 0.0050 (5) −0.0056 (5) −0.0003 (5)Geometric parameters (Å, º) C1—C2 1.489 (2) C8—O5 1.425 (2)C1—H1A 0.98 C8—O4 1.446 (2)C1—H1B 0.98 C8—C9 1.493 (3)C1—H1C 0.98 C8—H8 1C2—O1 1.206 (2) C9—H9A 0.98C2—O2 1.3514 (19) C9—H9B 0.98C3—O2 1.4394 (18) C9—H9C 0.98C3—C4 1.508 (2) C10—O6 1.4461 (19)C3—C7 1.520 (2) C10—H10A 0.99C3—H3 1 C10—H10B 0.99C4—O8 1.4420 (19) C11—O7 1.205 (2)C4—C5 1.524 (2) C11—O6 1.350 (2)C4—H4 1 C11—C12 1.493 (2)C5—O3 1.433 (2) C12—H12A 0.98C5—C10 1.506 (2) C12—H12B 0.98C5—H5 1 C12—H12C 0.98C6—O4 1.399 (2) C13—O9 1.201 (2)C6—O3 1.422 (2) C13—O8 1.3620 (19)C6—C7 1.530 (2) C13—C14 1.492 (2)C6—H6 1 C14—H14A 0.98C7—O5 1.424 (2) C14—H14B 0.98C7—H7 1 C14—H14C 0.98C2—C1—H1A 109.5 O4—C8—C9 112.28 (15)C2—C1—H1B 109.5 O5—C8—H8 109.9H1A—C1—H1B 109.5 O4—C8—H8 109.9C2—C1—H1C 109.5 C9—C8—H8 109.9H1A—C1—H1C 109.5 C8—C9—H9A 109.5H1B—C1—H1C 109.5 C8—C9—H9B 109.5O1—C2—O2 122.85 (14) H9A—C9—H9B 109.5O1—C2—C1 126.29 (15) C8—C9—H9C 109.5O2—C2—C1 110.86 (13) H9A—C9—H9C 109.5O2—C3—C4 107.19 (12) H9B—C9—H9C 109.5O2—C3—C7 110.99 (12) O6—C10—C5 108.84 (13)C4—C3—C7 111.54 (13) O6—C10—H10A 109.9O2—C3—H3 109 C5—C10—H10A 109.9C4—C3—H3 109 O6—C10—H10B 109.9C7—C3—H3 109 C5—C10—H10B 109.9O8—C4—C3 108.04 (12) H10A—C10—H10B 108.3O8—C4—C5 108.55 (12) O7—C11—O6 123.81 (15)C3—C4—C5 109.08 (12) O7—C11—C12 125.78 (16)O8—C4—H4 110.4 O6—C11—C12 110.40 (14)C3—C4—H4 110.4 C11—C12—H12A 109.5C5—C4—H4 110.4 C11—C12—H12B 109.5O3—C5—C10 107.89 (13) H12A—C12—H12B 109.5supplementary materialssup-6Acta Cryst. (2012). E68, o2520    O3—C5—C4 107.58 (12) C11—C12—H12C 109.5C10—C5—C4 114.01 (13) H12A—C12—H12C 109.5O3—C5—H5 109.1 H12B—C12—H12C 109.5C10—C5—H5 109.1 O9—C13—O8 123.42 (15)C4—C5—H5 109.1 O9—C13—C14 126.07 (16)O4—C6—O3 106.79 (13) O8—C13—C14 110.51 (14)O4—C6—C7 102.44 (12) C13—C14—H14A 109.5O3—C6—C7 112.54 (12) C13—C14—H14B 109.5O4—C6—H6 111.5 H14A—C14—H14B 109.5O3—C6—H6 111.5 C13—C14—H14C 109.5C7—C6—H6 111.5 H14A—C14—H14C 109.5O5—C7—C3 109.66 (13) H14B—C14—H14C 109.5O5—C7—C6 101.86 (12) C2—O2—C3 116.85 (12)C3—C7—C6 114.39 (13) C6—O3—C5 114.45 (12)O5—C7—H7 110.2 C6—O4—C8 108.62 (12)C3—C7—H7 110.2 C7—O5—C8 107.27 (12)C6—C7—H7 110.2 C11—O6—C10 117.71 (13)O5—C8—O4 106.08 (13) C13—O8—C4 117.42 (12)O5—C8—C9 108.69 (15)Hydrogen-bond geometry (Å, º) D—H···A D—H H···A D···A D—H···AC1—H1C···O3i 0.98 2.55 3.511 (2) 167C8—H8···O7i 1.00 2.49 3.317 (2) 140C12—H12A···O4ii 0.98 2.56 3.469 (2) 154C12—H12B···O1iii 0.98 2.51 3.460 (2) 163C14—H14B···O9iv 0.98 2.53 3.361 (2) 142Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) −x+3/2, −y+2, z+1/2; (iii) −x+1, y+1/2, −z+1/2; (iv) x−1/2, −y+3/2, −z+1.

3,4,6-Tri-O-acetyl-1,2-[(S)-ethylidene]-β- D-mannopyranose

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3,4,6-Tri-O-acetyl-1,2-[(S)-ethylidene]-β- D-mannopyranose

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