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

Temperature

60 °C

Water (0.15 mL), cyclobutanone (1 g, 14.27 mmol) and acetic acid (1.742 mL, 30.44 mmol) were added to a stirred solution of tert-butyl piperazine-1-carboxylate (1.772 g, 9.51 mmol) in THF (20 mL) under nitrogen. Sodium cyanoborohydride (0.897 g, 14.27 mmol) was added portion wise over a period of 10 mins. The resulting mixture was stirred at 60° C. for 20 h. The reaction mixture was evaporated to dryness and mixed with water (40 mL) and 1M HCl (15 mL). The solution was washed with EtOAc (2×25 mL), basified with solid K2CO3 and extracted with EtOAc (2×15 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 (1.155 g, 50.5%) as a colourless oil.

1. customThe reaction mixture was evaporated to dryness
2. additionmixed with water (40 mL) and 1M HCl (15 mL)
3. washThe solution was washed with EtOAc (2×25 mL)
4. extractionextracted with EtOAc (2×15 mL)
5. washThe organic layer was washed with saturated brine
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. customevaporated

ORD record

ord-434fd138f4dd4c9a82375bc7ddcf52ad

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07737149B2