Reaktion #8921

Reaktionsgleichung

N-benzyloxycarbonyl-L-phenylalanine chloromethyl ketone

sodium borohydride

→

N-benzyloxycarbonyl-3(S)-amino-1-chloro-4-phenyl-2(S)-butanol

Ausbeute 48.4%

Lösungsmittel

methanol

tetrahydrofuran

—

hexanes

Reaktionsbedingungen

Aufarbeitung

1. 1
   Einengenconcentrated in vacuo
2. 2
   workup.DISSOLUTIONThe residue was dissolved in 1000 mL of ethyl acetate
3. 3
   Waschenwashed with 1N KHSO4, saturated aqueous NaHCO3, saturated aqueous NaCl
4. 4
   Trocknendried over anhydrous MgSO4
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated in vacuo
7. 7
   Sonstigeto give an oil
8. 8
   Temperaturto cool to room temperature where upon crystals
9. 9
   Sonstigeformed
10. 10
    Sonstigethat were isolated by filtration
11. 11
    Waschenwashed with copious amounts of hexanes
12. 12
    SonstigeThis solid was then recrystallized from hot ethyl acetate and hexanes

Vorschrift

To a solution of N-benzyloxycarbonyl-L-phenylalanine chloromethyl ketone (75 g, 0.2 mol) in a mixture of 800 mL of methanol and 800 mL of tetrahydrofuran was added sodium borohydride (13.17 g, 0.348 mol, 1.54 equiv.) over 100 min. The solution was stirred at room temperature for 2 hours and then concentrated in vacuo. The residue was dissolved in 1000 mL of ethyl acetate and washed with 1N KHSO4, saturated aqueous NaHCO3, saturated aqueous NaCl, dried over anhydrous MgSO4, filtered and concentrated in vacuo to give an oil. The crude product was dissolved in 1000 mL of hexanes at 60° C. and allowed to cool to room temperature where upon crystals formed that were isolated by filtration and washed with copious amounts of hexanes. This solid was then recrystallized from hot ethyl acetate and hexanes to provide 32.3 g 43% of N-benzyloxycarbonyl-3(S)-amino-1-chloro-4-phenyl-2(S)-butanol, mp 150–151° C., FAB MS: MLi+=340.

Quelle