Triethylamine → tert-Butyl 4-(2-methoxy-2-oxo-1-phenylethyl)piperazine-1-carboxylate

HRID 352192Notes

Reaction equation

HRID 352192 reaction equation
[CH3:1][O:2][C:3](=[O:12])[CH:4]([C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1)Br.CCN(CC)CC.[C:20]([N:27]1[CH2:32][CH2:31][NH:30][CH2:29][CH2:28]1)([O:22][C:23]([CH3:26])([CH3:25])[CH3:24])=[O:21]>O1CCCC1>[C:23]([O:22][C:20]([N:27]1[CH2:32][CH2:31][N:30]([CH:4]([C:3]([O:2][CH3:1])=[O:12])[C:6]2[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=2)[CH2:29][CH2:28]1)=[O:21])([CH3:26])([CH3:24])[CH3:25]

Participants

5

Reactant 3

HCID 8471TriethylamineHCID 137806Benzeneacetic acid, alpha-bromo-, methyl esterHCID 143452tert-Butyl piperazine-1-carboxylate

Product 1

HCID 23386132tert-Butyl 4-(2-methoxy-2-oxo-1-phenylethyl)piperazine-1-carboxylateYield 100%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of racemic α-bromophenylacetic acid methyl ester, 5.0 g (22.0 mmol) in 200 mL of tetrahydrofuran was added 3.4 mL (22.0 mmol) of Et3N and 12.3 g (66.0 mmol) of BOC-piperazine. The reaction mixture was refluxed for 3.5 hours, cooled to rt. and concentrated to dryness. The residue was partitioned between 20% isopropanol/chloroform and water. The mixture was washed with saturated NaHCO3, washed with brine, dried over Na2SO4, filtered and concentrated to dryness. The residue was purified by chromatography using chloroform as eluent and was concentrated to dryness to yield 7.73 g (100%) of the desired mixture of isomers as a colorless oil.

Workup

  1. temperatureThe reaction mixture was refluxed for 3.5 hours
  2. concentrationand concentrated to dryness
  3. customThe residue was partitioned between 20% isopropanol/chloroform and water
  4. washThe mixture was washed with saturated NaHCO3
  5. washwashed with brine
  6. dry with materialdried over Na2SO4
  7. filtrationfiltered
  8. concentrationconcentrated to dryness
  9. customThe residue was purified by chromatography
  10. concentrationwas concentrated to dryness

Sources & evidence

ORD record
ord-95c7c8f3110c4250844adfaef9c75880
Source dataset
uspto-grants-2004_06
Patent number
US06743794B2

Reaction notes

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