反应详情

A solution of benzyl2-acetamido-3,6-di-O-benzyl-2,4-dideoxy-4-fluoro-α-D-glucopyranose (3.21 g, 6.51 mmol) in the HOAc (150 ml) containing 10% Pd/charcoal catalyst (4.3 g) was hydrogenated at 50–55 psig. Pressure dropped from 55 to 50 psig and was re-pressurized to 56 psig. Again, pressure dropped to approximately 50 psig. A small sample was withdrawn. The reaction appeared to have made a little progress, but much starting material remained as shown by TLC. Catalyst was removed by filtration through a layer of Celite, which was washed with H2O and EtOH. The filtrate was evaporated in vacuo to low bulk then again clarified by filtration through a layer of Celite. This filtrate was now evaporated in vacuo to a dry solid, which was dried in vacuo for 18 hours. Yield=2.57 g. The reaction was then re-started by dissolving 2.01 g (5.09 mmol) of the product in glacial HOAc (50 ml) containing 2.65 g of 10% Pd/charcoal catalyst, using a Parr shaker apparatus, to hydrogenate at 50 psig for 5 days. A sample was withdrawn, membrane-filtered, then evaporated in vacuo to a residue. This material was checked via TLC and the reaction appeared to have been successful, although a small amount of unknown material showed just ahead of the product. The remainder of the reaction catalyst was removed by filtration through a layer of Celite. The filtrate was evaporated in vacuo to a residue, which was dried in vacuo 18 hours; Yield=2.67 g. This material was now triturated in warm absolute EtOH (approx. 25 ml). Ether was added, in portions (250–300 ml). A tan solid appeared. The supernatent liquid was removed by decontation; the residue was dried in vacuo Yield=1.35 g (54.6%).

1. additionPressure dropped from 55 to 50 psig
2. additionAgain, pressure dropped to approximately 50 psig
3. customA small sample was withdrawn
4. customCatalyst was removed by filtration through a layer of Celite, which
5. washwas washed with H2O and EtOH
6. customThe filtrate was evaporated in vacuo to low bulk
7. filtrationthen again clarified by filtration through a layer of Celite
8. customThis filtrate was now evaporated in vacuo to a dry solid, which
9. customwas dried in vacuo for 18 hours
10. customA sample was withdrawn
11. filtrationmembrane-filtered
12. customevaporated in vacuo to a residue
13. customThe remainder of the reaction catalyst was removed by filtration through a layer of Celite
14. customThe filtrate was evaporated in vacuo to a residue, which
15. customwas dried in vacuo 18 hours
16. customThis material was now triturated in warm absolute EtOH (approx. 25 ml)
17. additionEther was added, in portions (250–300 ml)
18. customThe supernatent liquid was removed by decontation
19. customthe residue was dried in vacuo Yield=1.35 g (54.6%)