反应详情

Boron trifluoride etherate (700 μl, 5.5 mmol) is added to a solution of methyl 2,4,7,8,9-penta-O-acetyl-N-acetyl-D-neuraminate (1.01 g, 1.96 mmol) and 6-(5-cholesten-3β-yloxy)-hexane-1-thiol (0.98 g, 1.96 mmol) in dry chloroform (5 ml). The mixture is stirred under nitrogen for 5 hours at room temperature, and washed with aqueous sodium bicarbonate and water. The dried solution is concentrated to a residue which is put on a silica gel column and eluted with chloroform-ethyl ether-methanol (31:10:1). The β-anomer is isolated as a glass (400 mg), [α]D -38.5° (c 1.5, chloroform).

1. washwashed with aqueous sodium bicarbonate and water
2. concentrationThe dried solution is concentrated to a residue which
3. washeluted with chloroform-ethyl ether-methanol (31:10:1)