Benzyl Bromide → Tert-butyl 4-benzyl-3-oxopiperazine-1-carboxylate

HRID 1672152Notes

Reaction equation

HRID 1672152 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].[CH2:17](Br)[C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1>>[C:3]([O:7][C:8]([N:10]1[CH2:15][CH2:14][N:13]([CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[C:12](=[O:16])[CH2:11]1)=[O:9])([CH3:6])([CH3:4])[CH3:5]

Participants

4

Reactant 3

HCID 7498Benzyl BromideHCID 24758Sodium hydrideHCID 3157178Tert-butyl 3-oxopiperazine-1-carboxylate

Product 1

HCID 10891590Tert-butyl 4-benzyl-3-oxopiperazine-1-carboxylateYield 143.5%

Procedure

Sodium hydride (60%, 18.11 g, 452 mmol) in mineral oil was triturated with 35 hexanes, dried under a stream of nitrogen and taken up in 1500 mL of THF. To the slurry at 0° C. was added 3-oxo-piperazine-1-carboxylic acid tert-butyl ester (75.057 g, 200.4 mmol) in portions over 15 min. After 90 minutes benzyl bromide (71.01 g, 415.1 mmol) was added and the mixture was warmed to room temperature for 18 hours. The solution was quenched with H2O and extracted with Et2O. The combined organic layers were washed with H2O, washed with brine, dried over MgSO4. Concentration in vacuo gave a crude solid which was recrystallized from hexane to afford 4-benzyl-3-oxo-piperazine-1-carboxylic acid tert-butyl ester (83.5 g, 76%) as a white crystalline solid.

Workup

  1. customdried under a stream of nitrogen
  2. customThe solution was quenched with H2O
  3. extractionextracted with Et2O
  4. washThe combined organic layers were washed with H2O
  5. washwashed with brine
  6. dry with materialdried over MgSO4
  7. concentrationConcentration in vacuo
  8. customgave a crude solid which
  9. customwas recrystallized from hexane

Sources & evidence

ORD record
ord-48960d58ef184d9589fcc9db501cccb6
Source dataset
uspto-grants-2011_08
Patent number
US07998963B2

Reaction notes

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