| Popis: |
2-Methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-α-D-glucopyrano)-[2,1-d]-2-oxazoline (5) was reacted with glycosyl acceptors bearing primary (6, 8, 10, 20) or secondary hydroxy groups (12, 14, 16, 18) in the presence of anhydrous cupric bromide or cupric chloride at elevated temperature to provide 2-acetamido- 2-deoxy-β-D-glucopyranosides in 36-92% yield. The reaction conditions are milder than those previously described for oxazoline activation employing p-toluenesulfonic acid or ferric chloride. Treatment of the oxazoline with trimethylsilyl azide (22) and CuCl2 leads to 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-D-glucopyranosyl azide (23) in 69% yield. |
