Реакция #44471

Уравнение реакции

Benzyl(R)-2-((S)-2,5-dihydrofuran-2-yl)-2-hydroxyethylcarbamate

ammonium chloride

bromotosylate

(3S,3aS,6S,6aS)-6-Bromohexahydrofuro[3,2-b]furan-3-yl 4-methylbenzenesulfonate

ammonia

→

(R)-2-amino-1-((S)-2,5-dihydrofuran-2-yl)ethanol

Растворители

water

propan-2-ol

methanol

propan-2-ol

Условия реакции

Обработка

1. 1
   Фильтрацияbefore filtering the suspension through celite in vacuo
2. 2
   ПромывкаThe filter cake was washed with diethyl ether (60 mL)
3. 3
   workup.ADDITIONHydrochloric acid (1M, 60 mL) was added to the filtrate
4. 4
   Другоеthe organic phase separated
5. 5
   ЭкстракцияThe aqueous layer was extracted with diethyl ether (60 mL)
6. 6
   Промывкаthe combined organic phase was washed with brine (60 mL)
7. 7
   Сушкаdried (MgSO4)
8. 8
   Фильтрацияfiltered
9. 9
   workup.DISSOLUTIONThe residue was dissolved in ammonium hydroxide (18 mL)
10. 10
    Другоеthe solvents were removed in vacuo
11. 11
    ДругоеThe residue was azeotroped with diethyl ether (3×10 mL)

Методика

Alternative preparation of Benzyl(R)-2-((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.

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