H₂SO₄-Silica Promoted Direct Formation of β-Glycosides of N-Acetyl Glycosylamines under Microwave Conditions

Abstract

N-Acetyl glycosamines are important building blocks for the synthesis of biologically active oligosaccharides. This communication describes a simple direct protocol for the synthesis of β-glycosides of N-acetyl glycosylamines from easily accessible per-O-acetyl derivatives of of N-acetyl glycosylamines using H₂SO₄-silica as promoter under microwave conditions. The protocol is suitable for alcohol or sugar acceptors.

Key words

carbohydrates - glycosylations - supported catalysis - microwave - stereoselective synthesis

References and Notes

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Preparation of H ₂ SO ₄ -Silica
To a slurry of silica gel (10 g, 230-400 mesh) in dry Et₂O (50 mL) was added concd H₂SO₄ (1 mL) and the slurry shaken for 5 min. The solvent was evaporated under reduced pressure resulting in free-flowing H₂SO₄-silica which was dried at 110 ˚C for 3 h and used for the reactions.