Homoallyl bromide → Tert-butyl 4-but-3-enyl-3-oxopiperazine-1-carboxylate

HRID 559323Notes

Reaction equation

HRID 559323 reaction equation
[H-].[Na+].[C:3]([O:7][C:8]([N:10]1[CH2:15][CH2:14][NH:13][C:12](=[O:16])[CH2:11]1)=[O:9])([CH3:6])([CH3:5])[CH3:4].Br[CH2:18][CH2:19][CH:20]=[CH2:21]>CN(C)C=O.O1CCCC1>[C:3]([O:7][C:8]([N:10]1[CH2:15][CH2:14][N:13]([CH2:21][CH2:20][CH:19]=[CH2:18])[C:12](=[O:16])[CH2:11]1)=[O:9])([CH3:6])([CH3:4])[CH3:5]

Participants

6

Reactant 3

HCID 21241Homoallyl bromide2×HCID 24758Sodium hydrideHCID 3157178Tert-butyl 3-oxopiperazine-1-carboxylate

Product 1

HCID 57445033Tert-butyl 4-but-3-enyl-3-oxopiperazine-1-carboxylateYield 85.3%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 8028TetrahydrofuranSolvent

Procedure

Sodium hydride (60% dispersion in mineral oil, 42 mg, 1.05 mmol) was added at room temperature to a solution of 3-oxo-piperazine-1-carboxylic acid tert-butyl ester (200 mg, 1.00 mmol) in N,N-dimethylformamide (4 ml), then after 10 min a solution of 4-bromo-1-butene (148 mg, 1.10 mmol) in tetrahydrofuran (1 ml) was added dropwise. The reaction mixture was stirred for 3 h at room temperature, then another portion of 4-bromo-1-butene (40 mg, 0.30 mmol) was added dropwise, and the reaction mixture was heated at 50° C. for 18 h. After cooling, the reaction mixture was partitioned between water and heptane/ethyl acetate 1:1. The organic layer was washed with brine, dried (MgSO4), and evaporated. Chromatography (SiO2; heptane/ethyl acetate 1:1) afforded the title compound (217 mg, 81%). Colorless oil, MS (ISP)=255.2 (M+H)+.

Workup

  1. temperaturethe reaction mixture was heated at 50° C. for 18 h
  2. temperatureAfter cooling
  3. customthe reaction mixture was partitioned between water and heptane/ethyl acetate 1:1
  4. washThe organic layer was washed with brine
  5. dry with materialdried (MgSO4)
  6. customevaporated

Sources & evidence

ORD record
ord-4dc888e857034dc99ac58e0e33a0a558
Source dataset
uspto-grants-2011_11
Patent number
US08063042B2

Reaction notes

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