Reaktion #1751903

Reaktionsgleichung

acetic acid

[(1-ethoxycyclopropyl)oxy]trimethylsilane

NaCNBH3

THF

tert-Butyl 3,9-diazaspiro[5.5]undecane-3-carboxylate

→

tert-Butyl 9-cyclopropyl-3,9-diazaspiro[5.5]undecane-3-carboxylate

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstige3 g of molecular sieves (3 Å, which had been dried beforehand under high vacuum)
2. 2
   workup.ADDITIONwere added to this solution
3. 3
   Temperaturthe mixture was heated to 60° C.
4. 4
   workup.STIRRINGstirred at this temperature for about 15 h
5. 5
   FiltrationThe reaction mixture was filtered
6. 6
   Einengenthe filtrate was concentrated under reduced pressure
7. 7
   Waschenwashed successively with 1 M NaOH solution and NaCl solution
8. 8
   Trocknendried over MgSO4
9. 9
   SonstigeAfter the solvent had been removed under reduced pressure
10. 10
    Sonstigethe product was obtained as a colorless oil

Vorschrift

tert-Butyl 3,9-diazaspiro[5.5]undecane-3-carboxylate (250 mg, 0.98 mmol) were dissolved in 10 ml of absolute methanol. 3 g of molecular sieves (3 Å, which had been dried beforehand under high vacuum) were added to this solution. Under argon, glacial acetic acid (0.55 ml, 10 eq.), [(1-ethoxycyclopropyl)oxy]trimethylsilane (0.69 ml, 3.5 eq.) and 4.4 ml of a 1 M NaCNBH3 solution in THF (4.4 mmol, 4.5 eq.) were then added successively. After stirring at RT for 20 minutes, the mixture was heated to 60° C. and stirred at this temperature for about 15 h. The reaction mixture was filtered and the filtrate was concentrated under reduced pressure. The residue was taken up in dichloromethane, washed successively with 1 M NaOH solution and NaCl solution, and dried over MgSO4. After the solvent had been removed under reduced pressure, the product was obtained as a colorless oil.

Quelle