Реакция #1884982

Уравнение реакции

isopropyl 1-(tert-butoxycarbonyl)pyrrolidin-5-one-2(S)-carboxylate

sodium borohydride

ethyl acetate hexane

→

isopropyl 2(S)-(tert-butoxycarbonylamino)-5-hydroxypentanoate

Выход 64.0%

Растворители

methanol

water

Условия реакции

Обработка

1. 1
   Экстракцияextracted with ether
2. 2
   Промывкаwashed with saturated aqueous NaCl
3. 3
   Сушкаdried (MgSO4)
4. 4
   Другоеevaporated
5. 5
   Другоеto give a light yellow oil

Методика

To a solution of isopropyl 1-(tert-butoxycarbonyl)pyrrolidin-5-one-2(S)-carboxylate (product of step 26B, 49.5 g, 183 mmol) in methanol (300 mL) was added sodium borohydride (10.0 g, 263 mmol) in ˜1 g portions over 1.5 hours. The reaction was stirred under nitrogen for another 10 minutes. It was diluted with water, extracted with ether, combined organic fractions washed with saturated aqueous NaCl, dried (MgSO4) and evaporated to give a light yellow oil. Flash chromatography (silica gel, 20-30% ethyl acetate/hexane) gave 31.8 g (64%) of isopropyl 2(S)-(tert-butoxycarbonylamino)-5-hydroxypentanoate as a colorless syrup: 1H NMR (300 MHz, Chloroform-D) δ 5.16 (br d, 1 H, J=7.3 Hz), 5.03 (sept., 1 H, J=6.2 Hz), 4.28 (br d, 1 H, J=6.2 Hz), 3.67 (br dd, J=10.2, 5.5 Hz), 1.94-1.79 (m, 2 H), 1.76-1.67 (m, 1 H), 1.66-1.56 (m, 2 H), 1.43 (s, 9 H), 1.25 (d, 3 H, J=6.2 Hz), 1.23 (d, 3 H, J=6.2 Hz). LCMS m/z 276 (M+H)+.

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