反应详情

A solution of 1,2,3,4-tetra-O-acetyl-6-deoxy-phthalimido-D-galactopyranose (4.2 g.) in dichloromethane (2 ml.) is treated with 30-32% hydrobromic acid in glacial acetic acid (10 ml.) for 1 hour. The reaction mixture is poured into ice-water, and the product is immediately extracted with dichloromethane. The organic layer is washed with cold aqueous sodium hydrogencarbonate and cold water, dried, and evaporated in vacuo to give the title compound as a syrup (4.0 g., 91%); n.m.r. (chloroform-d): ∂ 6.63 (d, J1,2 4.0 Hz, H-1), 7.58-7.90 (4 aromatic), 1.96, 2.07 and 2.13 (3 OAc).

1. extractionthe product is immediately extracted with dichloromethane
2. washThe organic layer is washed with cold aqueous sodium hydrogencarbonate and cold water
3. customdried
4. customevaporated in vacuo