Reaktion #45099

Reaktionsgleichung

tert-butyl piperazine-1-carboxylate

[(1-ethoxycyclopropyl)oxy]trimethylsilane

acetic acid

sodium cyanoborohydride

→

tert-butyl 4-cyclopropylpiperazine-1-carboxylate

Ausbeute 68.3%

Lösungsmittel

tetrahydrofuran

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture was cooled
2. 2
   Filtrationfiltered
3. 3
   Sonstigeevaporated to dryness
4. 4
   workup.ADDITION1N HCl (40 ml) and water (60 ml) were added
5. 5
   Extraktionthe solution extracted with ethyl acetate (3×50 ml)
6. 6
   Extraktionextracted with ethyl acetate (4×50 ml)
7. 7
   WaschenThe organic extracts were washed with saturated sodium chloride solution (50 ml)
8. 8
   Trocknendried over MgSO4
9. 9
   Filtrationfiltered
10. 10
    Sonstigeevaporated to dryness

Vorschrift

A solution of tert-butyl piperazine-1-carboxylate (9.31 g, 50 mmol), [(1-ethoxycyclopropyl)oxy]trimethylsilane (20.11 mL, 100.00 mmol) and acetic acid(14.31 mL, 250.00 mmol) in tetrahydrofuran (100 mL), methanol (10 mL) was treated with sodium cyanoborohydride (4.71 g, 75.00 mmol) at 20° C. The resulting solution was stirred at 60° C. for 18 h. The reaction mixture was cooled, filtered and evaporated to dryness. 1N HCl (40 ml) and water (60 ml) were added and the solution extracted with ethyl acetate (3×50 ml). The aqueous layer was basified to pH 10 with solid potassium carbonate and extracted with ethyl acetate (4×50 ml). The organic extracts were washed with saturated sodium chloride solution (50 ml) and dried over MgSO4, filtered and evaporated to dryness to give tert-butyl 4-cyclopropylpiperazine-1-carboxylate (7.73 g, 68.3%) as a white waxy solid.

Quelle