반응 #450535

반응 방정식

dichloromethane

tetra-O-acetyl-6-chloro-6-deoxy-D-galactopyranose

compound 54

tetra-O-acetyl-6-chloro-6-deoxy-D-galactopyranose

hydrazine acetate

→

2,3,4-tri-O-acetyl-6-chloro-6-deoxy-α-D-galactopyranose

수율 103.1%

용매

DMF

반응 조건

후처리

1. 1
   세척the resulting solution washed 4 times with water
2. 2
   건조The organic layer was dried over anhydrous sodium sulfate
3. 3
   기타evaporated

실험 절차

To a solution of tetra-O-acetyl-6-chloro-6-deoxy-D-galactopyranose (compound 54) (6.36 g, 17.3 mmol) in DMF (60 mL) was added hydrazine acetate (2.4 g, 26.0 mmol). The mixture was stirred for 1 hour at room temperature and then 1 L of dichloromethane was added and the resulting solution washed 4 times with water. The organic layer was dried over anhydrous sodium sulfate and evaporated. Flash column chromatography using hexane-ethyl acetate (1:1) as the eluent gave 2,3,4-tri-O-acetyl-6-chloro-6-deoxy-α-D-galactopyranose (5.79 g). This material was dissolved in 50 mL of dichloromethane and cooled to 0° C. Trichloroacetonitrile (8.93 mL, 89.2 mmol) was added followed by DBU (1.33 mL, 8.9 mmol). This solution was stirred for 1.5 hours and then evaporated. The residue was chromatographed on a silica gel column, eluting with hexane-ethyl acetate (2:1), to provide compound 55 (4.1 g, 51%) as a foam.

출처