反应详情

A solution of 2,3,4-tri-O-acetyl-1-thio-β-L-fucopyranose (1.49 g, 4.87 mmol) and freshly crystallized 3-iodopropionic acid (0.97 g, 4.86 mmol) in dichloromethane (20 ml) containing triethylamine (1.35 ml) is kept for 16 hours at room temperature. Hydrochloric acid (2.5 N, 20 ml) and dichloromethane (10 ml) are added and the solution is washed with water, dried, and evaporated in vacuo to a residue that is put on a column of silica gel and eluted with chloroform-methanol-water, 92.5:7.5:0.75 (v/v/v). Compound 23 is isolated in 87% yield (1.6 g), and used, without further purification, for the preparation of 24.

1. washthe solution is washed with water
2. customdried
3. customevaporated in vacuo to a residue that
4. washeluted with chloroform-methanol-water, 92.5:7.5:0.75 (v/v/v)