反应详情

A solution of 2-acetamido-4-fluoro-2,4-dideoxy-D-glucopyranose (1.35 g, 6.048 mmol) in a mixture of pyridine (50 ml) and acetic anhydride (25 ml, 27 g, 264 mmol) was stirred at room temperature for 24 hours at which time no starting material but two close spots appeared by TLC. Stirring continued for another 15 hours. Solvent was then removed by evaporation in vacuo; the residue was now co-evaporated with toluene (4×50 ml) then dried in vacuo. This material was now adsorbed on 5 g of silica gel then placed on a silica gel column (45 g, 20×360 mm) poured in CH2Cl2/acetone (8:1). The column was eluted with 500 ml of CH2Cl2/acetone (8:1) followed by 500 ml of CH2Cl2/CH3OH (7:3). The product and trailing spots eluted immediately, with virtually no separation. The CH2Cl2/CH3OH flush produced a trailing spot. All were evaporated and dried in vacuo.

1. customclose spots
2. stirringStirring
3. waitcontinued for another 15 hours
4. customSolvent was then removed by evaporation in vacuo
5. customthen dried in vacuo
6. additionpoured in CH2Cl2/acetone (8:1)
7. washThe column was eluted with 500 ml of CH2Cl2/acetone (8:1)
8. washeluted immediately
9. customwith virtually no separation
10. customThe CH2Cl2/CH3OH flush
11. customproduced a trailing spot
12. customAll were evaporated
13. customdried in vacuo