反应详情

温度

75 °C

Alternative Preparation of Benzyl (S)-2-((S)-2,5-dihydrofuran-2-yl)-2-hydroxyethylcarbamate (17); Zinc and ‘One-Pot’ Procedure. A solution of ammonium chloride (140 mg, 2.62 mmol) in water (1.5 mL) was added to a solution of iodotosylate (38) (800 g, 1.95 mmol) in propan-2-ol (3 mL) and tetrahydrofuran (6 mL) under argon. Zinc dust (140 mg, 2.15 mmol) was then added in portions over 5 minutes then the suspension stirred for 16 hours before filtering through celite in vacuo. The filter cake was washed with diethyl ether (15 mL). Hydrochloric acid (1M, 15 mL) was added to the filtrate then the organic phase separated. The aqueous layer was extracted with diethyl ether (15 mL) then the combined organic phase was washed with brine (15 mL), then dried (MgSO4), filtered and reduced in vacuo. The residue (0.54 g) was dissolved in ammonium hydroxide (4.5 mL) and a solution of ammonia in 2-propanol (3 mL, 2.0M, 6 mmol) then heated in a sealed tube at 75° C. for 16 hours. The solvents were removed in vacuo (transfer assisted with methanol) then the residue azeotroped with diethyl ether (5 mL) before adding ammonium hydroxide (4.5 mL) and ammonia in 2-propanol (3 mL, 2.0M, 6 mmol). The suspension was heated in a sealed tube at 75° C. for 16 hours. The solvents were removed in vacuo (transfer assisted with methanol) then the residue azeotroped with diethyl ether (3×5 mL) to obtain (S)-2-amino-1-((S)-2,5-dihydrofuran-2-yl)ethanol which was used without further purification.

1. filtrationbefore filtering through celite in vacuo
2. washThe filter cake was washed with diethyl ether (15 mL)
3. additionHydrochloric acid (1M, 15 mL) was added to the filtrate
4. customthe organic phase separated
5. extractionThe aqueous layer was extracted with diethyl ether (15 mL)
6. washthe combined organic phase was washed with brine (15 mL)
7. dry with materialdried (MgSO4)
8. filtrationfiltered
9. dissolutionThe residue (0.54 g) was dissolved in ammonium hydroxide (4.5 mL)
10. customThe solvents were removed in vacuo (transfer assisted with methanol)
11. customthe residue azeotroped with diethyl ether (5 mL)
12. customThe solvents were removed in vacuo (transfer assisted with methanol)
13. customthe residue azeotroped with diethyl ether (3×5 mL)