Imidazole → 3,4,6-Tri-O-acetyl-2-azido-1-O-[tert-butyl(dimethyl)silyl]-2-deoxy-beta-D-glucopyranose

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Reaction Conditions

Reaction Steps

1,3,4,6-Tetra-O-acetyl-2-azido-2-deoxy-D-glucopyranose (30.2 g, 80 mmol) was coevaporated twice with toluene and dissolved in THF and methanol (7:3, 300 mL). The solution was cooled to 0° C. and gaseous anhydrous ammonia was bubbled through at a modest rate. After 15 min, nitrogen was bubbled through the solution to remove excess ammonia and the solvent was removed in vacuo to afford a brown oil. The residue was coevaporated twice with toluene and dissolved in CH2Cl2 (150 mL). Imidazole (10.9 g, 160 mmol) and tert-butyldimethylsilyl chloride (13.3 g, 88 mmol) were added. After 2 h, the mixture was diluted with EtOAc, washed with water, 1 N HCl (2×) and water. The organic layer was dried over MgSO4, filtered, and the solvent was removed in vacuo. Crystallization from ethanol afforded 2 (29.8 g, 67 mmol, 84%) as colorless crystals. 1H-NMR (300 MHz, CDCl3) δ 5.00-4.90 (m, 2H), 4.63 (d, J=7.6 Hz, 1H), 4.20 (dd, J=5.9, 12.1 Hz, 1H), 4.09 (dd, J=2.6, 12.1 Hz, 1H), 3.70-3.64 (m, 1H), 3.48-3.40 (m, 1H), 2.10 (s, 3H), 2.08 (s, 3H), 2.00 (s, 3H), 0.95 (s, 9H), 0.15 (s, 6H). The spectral data was in agreement with the reported data. (W. Kinzy, R. R. Schmidt, Liebigs Ann. Chem. 1985, 1537-1545; for the procedure see: B. La Ferla, L. Lay, M. Guerrini, L. Poletti, L. Panza, G. Russo, Tetrahedron 1999, 55, 9867-9880).

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