Acetic Acid → Tert-butyl 4-cyclobutylpiperazine-1-carboxylate

Temperatur

60 °C

Water (0.3 mL), cyclobutanone (2.000 g, 28.53 mmol) and acetic acid (3.48 mL, 60.86 mmol) were added to a stirred solution of tert-butyl piperazine-1-carboxylate (3.54 g, 19.02 mmol) in THF (40 mL) under nitrogen. Sodium cyanoborohydride (1.793 g, 28.53 mmol) was added portionwise over a period of 10 mins. The resulting mixture was stirred at 60° C. for 19 h. The reaction mixture was evaporated to dryness and mixed with water (80 mL) and 1M HCl (25 mL). The solution was washed with EtOAc (2×50 mL), basified with K2CO3 and extracted with EtOAc (2×30 mL). The organic layer was washed with saturated brine and dried over MgSO4, filtered and evaporated to afford pure tert-butyl 4-cyclobutylpiperazine-1-carboxylate (2.445 g, 53.5%) as a colourless oil.

1. customThe reaction mixture was evaporated to dryness
2. additionmixed with water (80 mL) and 1M HCl (25 mL)
3. washThe solution was washed with EtOAc (2×50 mL)
4. extractionextracted with EtOAc (2×30 mL)
5. washThe organic layer was washed with saturated brine
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. customevaporated

ORD-Eintrag

ord-d9ddea175d7547909e7151d1e5cfebeb

Quelldatensatz

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07737149B2