反应详情

温度

75 °C

Preparation of benzyl (R)-24(S)-2,5-dihydrofuran-2-yl)-2-hydroxyethylcarbamate (18). Zinc and ‘One-pot’ procedure. A solution of ammonium chloride (600 mg, 11.2 mmol) in water (7.5 mL) was added to a solution of bromotosylate (47) (3.0 g, 8.26 mmol) in propan-2-ol (15 mL) under argon. Zinc dust (600 mg, 9.2 mmol) was then added in portions over 4 minutes and the mixture was stirred for 16 hours before filtering the suspension through celite in vacuo. The filter cake was washed with diethyl ether (60 mL). Hydrochloric acid (1M, 60 mL) was added to the filtrate then the organic phase separated. The aqueous layer was extracted with diethyl ether (60 mL) then the combined organic phase was washed with brine (60 mL), then dried (MgSO4), filtered and reduced in vacuo. The residue was dissolved in ammonium hydroxide (18 mL) and a solution of ammonia in propan-2-ol (12 mL, 2.0M, 24 mmol), then divided into two equal portions and heated in sealed tubes at 75° C. for 16 hours. The mixtures were combined using methanol then the solvents were removed in vacuo. The residue was azeotroped with diethyl ether (3×10 mL) to obtain (R)-2-amino-1-((S)-2,5-dihydrofuran-2-yl)ethanol which was used without further purification.

1. filtrationbefore filtering the suspension through celite in vacuo
2. washThe filter cake was washed with diethyl ether (60 mL)
3. additionHydrochloric acid (1M, 60 mL) was added to the filtrate
4. customthe organic phase separated
5. extractionThe aqueous layer was extracted with diethyl ether (60 mL)
6. washthe combined organic phase was washed with brine (60 mL)
7. dry with materialdried (MgSO4)
8. filtrationfiltered
9. dissolutionThe residue was dissolved in ammonium hydroxide (18 mL)
10. customthe solvents were removed in vacuo
11. customThe residue was azeotroped with diethyl ether (3×10 mL)