反应详情

A 3 liter, 3-neck round bottom flask under N2 equipped with an addition funnel and overhead stirrer was charged with the product from Example 17E (32.35 g, 40.0 mmol) and anhydrous tetrahydrofuran (0.5 L). To the yellow solution was added tetrabutylammonium fluoride (1.0 M in THF, 32.0 mL, 32 mmol) at a fast drip rate. After the addition was completed the red, transparent solution was stirred for 3 hours, diluted with 1.0 L of water and 400 mL of EtOAc and stirred vigorously for 5 minutes. The layers were allowed to separate and the aqueous layer was removed and discarded. The organic layer was washed with a second liter of water and again the water was removed. The mix was diluted again with 1 L of water and 400 mL of EtOAc and stirred vigorously for 5 minutes to give an emulsion. The emulsion was broken by adding 50-100 mL of saturated brine and stirring gently. The organic layer was washed 4×1 L with water using brine as necessary to break the emulsions. After the final aqueous wash 400 mL of EtOAc was added and the suspension was stirred for 1 hour and the solid was collected by filtration, rinsed with 400 mL of EtOAc, rinsed with 500 mL of water and dried to constant mass in a vacuum oven (60° C., house vacuum, 24 hours) to give the title compound (22.6 g, 96%) as a cream colored powder.

1. customA 3 liter, 3-neck round bottom flask under N2 equipped with an addition funnel and overhead stirrer
2. additionAfter the addition
3. stirringstirred vigorously for 5 minutes
4. customto separate
5. customthe aqueous layer was removed
6. washThe organic layer was washed with a second liter of water
7. customagain the water was removed
8. additionThe mix was diluted again with 1 L of water and 400 mL of EtOAc
9. stirringstirred vigorously for 5 minutes
10. customto give an emulsion
11. stirringstirring gently
12. washThe organic layer was washed 4×1 L with water
13. washAfter the final aqueous wash 400 mL of EtOAc
14. additionwas added
15. stirringthe suspension was stirred for 1 hour
16. filtrationthe solid was collected by filtration
17. washrinsed with 400 mL of EtOAc
18. washrinsed with 500 mL of water
19. customdried to constant mass in a vacuum oven (60° C., house vacuum, 24 hours)