反应详情

The product of step B (20.3 g, 0.10 mol) was dissolved in 1,2-dichloroethane (100 mL) and oxalyl chloride (62.5 g, 0.49 mol) was added, followed by DMF (50 μL). The solution was stirred at room temperature until gas evolution ceased (c.a. 30 min). The solvent and excess oxalyl chloride was removed under reduced pressure, redissolved in 200 mL of 1,2-dichloroethane and evaporated under reduced pressure again. The residue was dissolved in dry THF (150 mL) under nitrogen and azidotrimethylsilane (12.7 g, 0.11 mol) was added. After stirring at room temperature for 5 min., the stirred solution was heated in a 70° C. oil bath until gas evolution ceased (c.a. 1 hour). The solution was cooled in an ice bath and concentrated aq. HCl (20 mL) was added all at once and the ice bath was removed. After gas evolution ceased (c.a. 15 min) the solvent was removed under reduced pressure and the residue was partitioned between water and ethyl acetate. The aqueous layer was made basic (250 mL of 1N NaOH) and extracted with ethyl acetate. The organic layer was washed successively with water and sat'd. NaCl, dried (MgSO4), filtered and evaporated under pressure. The residue was redissolved in 150 mL of ethyl acetate and 20 mL of dry 6.9N HCl/dioxone was added with stirring and icebath cooling. The white precipitate was filtered and washed with ethyl acetate then diethyl ether affording 16.9 g (80%) of product: m.p. 155°-160° C.

1. custom(c.a. 30 min)
2. customThe solvent and excess oxalyl chloride was removed under reduced pressure
3. dissolutionredissolved in 200 mL of 1,2-dichloroethane
4. customevaporated under reduced pressure again
5. dissolutionThe residue was dissolved in dry THF (150 mL) under nitrogen
6. stirringAfter stirring at room temperature for 5 min.
7. temperaturethe stirred solution was heated in a 70° C. oil bath until gas evolution
8. custom(c.a. 1 hour)
9. temperatureThe solution was cooled in an ice bath
10. customwas removed
11. custom(c.a. 15 min)
12. customwas removed under reduced pressure
13. customthe residue was partitioned between water and ethyl acetate
14. extractionextracted with ethyl acetate
15. washThe organic layer was washed successively with water
16. dry with materialNaCl, dried (MgSO4)
17. filtrationfiltered
18. customevaporated under pressure
19. dissolutionThe residue was redissolved in 150 mL of ethyl acetate
20. addition20 mL of dry 6.9N HCl/dioxone was added
21. stirringwith stirring
22. temperatureicebath cooling
23. filtrationThe white precipitate was filtered
24. washwashed with ethyl acetate