Acetic Acid → 1-Isopropylpiperazine dihydrochloride

To a solution of tert-butyl piperazine-1-carboxylate (100 g) and acetone (48 mL) in CH2Cl2 (1 L) was added acetic acid (31 mL) and NaBH(OAc)3 (170 g). The reaction mixture was stirred for 18 h, then was diluted with 1 N NaOH (500 mL), and extracted with CH2Cl2 (500 mL×2). The combined organic layers were dried (Na2SO4) and concentrated to a residue. The residue was dissolved in MeOH (200 mL) and 4 M HCl in 1,4-dioxin (700 mL) was added to the reaction mixture over a period of several hours. After 18 h, the reaction mixture was concentrated to yield a solid, which was washed with Et2O (500 mL×2) and dried overnight to yield the title compound as a white solid.

1. extractionextracted with CH2Cl2 (500 mL×2)
2. dry with materialThe combined organic layers were dried (Na2SO4)
3. concentrationconcentrated to a residue
4. dissolutionThe residue was dissolved in MeOH (200 mL)
5. addition4 M HCl in 1,4-dioxin (700 mL) was added to the reaction mixture over a period of several hours
6. waitAfter 18 h
7. concentrationthe reaction mixture was concentrated
8. customto yield a solid, which
9. washwas washed with Et2O (500 mL×2)
10. customdried overnight

ORD record

ord-705a0ce74fa4446a90d3c88d762d78cf

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07728129B2