Acetic Acid → tert-Butyl 4-cyclopropylpiperazine-1-carboxylate

Temperature

60 °C

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.

1. temperatureThe reaction mixture was cooled
2. filtrationfiltered
3. customevaporated to dryness
4. addition1N HCl (40 ml) and water (60 ml) were added
5. extractionthe solution extracted with ethyl acetate (3×50 ml)
6. extractionextracted with ethyl acetate (4×50 ml)
7. washThe organic extracts were washed with saturated sodium chloride solution (50 ml)
8. dry with materialdried over MgSO4
9. filtrationfiltered
10. customevaporated to dryness

ORD record

ord-96114825bb9d43c79c23579a8e9e0a18

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07737149B2