2-Acetyl­amino-1,3,4,6-tetra-O-(tri­methyl­silyl)-2-de­oxy-α-d-gluco­pyran­ose

Zhao-Dong Cheng; Yan-Li Cui; Jian-Wei Mao

doi:10.1107/S160053681301266X

. 2013 May 18;69(Pt 6):o917. doi: 10.1107/S160053681301266X

2-Acetylamino-1,3,4,6-tetra-O-(trimethylsilyl)-2-deoxy-α-d-glucopyranose

Zhao-Dong Cheng ^a, Yan-Li Cui ^a,^*, Jian-Wei Mao ^b

PMCID: PMC3685068 PMID: 23795087

Abstract

The title compound, C₂₀H₄₇NO₆Si₄, was synthesized by per-O-trimethylsilylation of N-acetyl-d-glucosamine using chlorotrimethylsilane in the presence of hexamethyldisiloxane. The trimethylsilyl group and acetamido group are located on the same side of the pyran ring, showing an α-configuration glycoside. One of the trimethylsilyl groups is disordered over two orientations, with site-occupancy factors of 0.625 (9) and 0.375 (9). In the crystal, N—H⋯O hydrogen bonds link the molecules into supramolecular chains along the a-axis direction.

Related literature

For background to the title compound, see: Augé et al. (1985 ▶); Ronnow et al. (1994 ▶); Du & Gervais-Hague (2005 ▶); Wang et al. (2007 ▶); Witschi & Gervais-Hague (2010 ▶). For related structures, see: Odinokov et al. (2002 ▶); Hu et al. (2011 ▶). For the synthesis, see: Loganathan & Trivedi (1987 ▶); Jervis et al. (2010 ▶).

Experimental

Crystal data

C₂₀H₄₇NO₆Si₄
M _r = 509.95
Orthorhombic,
a = 9.4500 (7) Å
b = 12.8824 (9) Å
c = 27.295 (3) Å
V = 3322.9 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.21 mm⁻¹
T = 293 K
0.38 × 0.20 × 0.19 mm

Data collection

Agilent Xcalibur (Atlas, Gemini ultra) diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ▶) T _min = 0.926, T _max = 0.962
9896 measured reflections
3438 independent reflections
2105 reflections with I > 2σ(I)
R _int = 0.046

Refinement

R[F ² > 2σ(F ²)] = 0.055
wR(F ²) = 0.149
S = 1.01
3438 reflections
309 parameters
183 restraints
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2011 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: OLEX2 (Dolomanov et al., 2009 ▶); software used to prepare material for publication: OLEX2.

Supplementary Material

Click here for additional data file.^{(32.5KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S160053681301266X/zq2199sup1.cif

e-69-0o917-sup1.cif^{(32.5KB, cif)}

Click here for additional data file.^{(168.6KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681301266X/zq2199Isup2.hkl

e-69-0o917-Isup2.hkl^{(168.6KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O3ⁱ	0.86	2.03	2.855 (4)	160

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was supported financially by the National Science Foundation of China (No. 30870553) and the Key International S&T Cooperation Project, China (No. 2010DFA34370).

supplementary crystallographic information

Comment

Per-O-trimethylsilylated glycopyranose was an useful intermediate for the construction of oligosaccharides and glycoconjugates (Du & Gervais-Hague, 2005). Per-trimethylsilylation of unprotected sugar could increase its solubility in organic solvents, and made selective acetylation available (Witschi et al., 2010). Hu et al. have developed an one-pot α-glycoside method which also used per-O-trimethylsilylated glycosides as starting materials (Hu et al., 2011; Wang et al., 2007). Currently we have applied considerable effort towards the construction of α-glycosides (Augé et al., 1985; Ronnow et al., 1994; Jervis et al., 2010). We have synthesized the title compound and report its crystal structure herein (for related structures, see: Odinokov et al., 2002; Hu et al., 2011).

The molecular structure of the title compound is shown in Fig. 1. In the molecule, the trimethylsilyl group and acetamido group are located on the same side of the pyran ring, showing α configuration glycoside. One of the trimethylsilyl group is disordered over two orientations with site-occupancy factors of 0.625 (9) and 0.375 (9). In the crystal structure, weak intermolecular N—H···O hydrogen bonds link the molecules into supramolecular chains along the a axis in the crystal (Fig. 2).

Experimental

To a solution of N-acetyl-D-glucosamine (1.0 g, 4.52 mmol) in pyridine (10 mL), hexamethyldisiloxane (HMDS) (8.0 mL, 38.90 mmol) and chlorotrimethylsilane (TMSCl) (4.0 mL, 31.64 mmol) were added sequentially. The solution was stirred at 353 K under a nitrogen atmosphere for 2 hours. After cooling to rt the mixture was poured into ice-water and extracted with hexane. The organic layers were washed with brine, dried with MgSO₄, filtered, and concentrated in vacuum to furnish the crude product. The residue was purified by silica gel chromatography (petroether/ethyl acetate = 15:1) to afford the title compound. The crystal suitable for X-ray data collection was obtained by slow evaporation from a methanol solution (Jervis et al., 2010; Loganathan et al., 1987).