Borane;tetrahydrofuran → (S)-2-Benzylpiperazine

HRID 1784695Notes

Reaction equation

HRID 1784695 reaction equation
[CH2:1]([C@@H:8]1[NH:13][C:12](=O)[CH2:11][NH:10][C:9]1=O)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.B.O1CCCC1>O1CCCC1>[CH2:1]([C@H:8]1[CH2:9][NH:10][CH2:11][CH2:12][NH:13]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 2723981Borane;tetrahydrofuranHCID 7076549Cyclo(-Gly-Phe)

Product 1

HCID 20760001(S)-2-BenzylpiperazineYield 40.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a suspension of (S)-3-benzyl-2,5-dioxopiperazine (2.284 g, 11.18 mmol) in tetrahydrofuran (20 mL) was added borane-tetrahydrofuran complex (49 mL, 1.0 M solution in THF, 49 mmol) at room temperature. The resulting mixture was refluxed for several hours before it was quenched with methanol at 0° C. After concentration in vacuo, the residue was treated with 10% sodium hydroxide aqueous solution, which was extracted with dichloromethane thoroughly. The organic layer was washed with water, dried over anhydrous sodium sulfate, and concentrated in vacuo to afford white crystals, which were washed with ether to yield (S)-2-benzylpiperazine (795 mg, 40.3%).

Workup

  1. temperatureThe resulting mixture was refluxed for several hours before it
  2. customwas quenched with methanol at 0° C
  3. concentrationAfter concentration in vacuo
  4. additionthe residue was treated with 10% sodium hydroxide aqueous solution, which
  5. extractionwas extracted with dichloromethane thoroughly
  6. washThe organic layer was washed with water
  7. dry with materialdried over anhydrous sodium sulfate
  8. concentrationconcentrated in vacuo
  9. customto afford white crystals, which
  10. washwere washed with ether

Sources & evidence

ORD record
ord-f1d429434cc449ce9006358226a97478
Source dataset
uspto-grants-2009_03
Patent number
US07504411B2

Reaction notes

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