Ethylenediamine → 2-Phenylpiperazine

HRID 2068657Notes

Reaction equation

HRID 2068657 reaction equation
[CH2:1]([NH2:4])[CH2:2][NH2:3].O.[C:6]1([C:12]([CH:14]=O)=O)[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.[BH4-].[Na+]>O>[C:6]1([CH:12]2[CH2:14][NH:4][CH2:1][CH2:2][NH:3]2)[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1

Participants

5

Reactant 3

HCID 3301EthylenediamineHCID 4311764Sodium borohydrideHCID 12215922Glyoxal, phenyl-, hydrate

Product 1

HCID 2506732-PhenylpiperazineYield 58.6%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To a stirring solution of ethylenediamine (1.2 g, 20.0 mmol) in IMS (10 mL) was added a solution of phenylglyoxal hydrate (3.0 g, 20.0 mmol) in IMS (20 mL) dropwise. The resultant solution was stirred at room temperature for 3 hours and then sodium borohydride was added and the reaction mixture stirred over the weekend. Water (25 mL) was added and stirring continued for 15 minutes then the ethanol was removed by evaporation. A further amount of water (25 mL) was added and the solution was extracted with DCM (×3) then the combined organics were washed with brine, dried and the solvent evaporated. The material was purified by column chromatography using a silica II cartridge, eluting with 0-20% ammonia in methanol to afford 2-phenyl-piperazine as a pale yellow-orange solid (1.9 g). LCMS m/z 163.36 [M+H]+ R.T.=0.34 min (Analytical Method 6).

Workup

  1. stirringstirring
  2. customthe ethanol was removed by evaporation
  3. additionA further amount of water (25 mL) was added
  4. extractionthe solution was extracted with DCM (×3)
  5. washthe combined organics were washed with brine
  6. customdried
  7. customthe solvent evaporated
  8. customThe material was purified by column chromatography
  9. washeluting with 0-20% ammonia in methanol

Sources & evidence

ORD record
ord-45ba996294964521b36c20be94c824a7
Source dataset
uspto-grants-2012_10
Patent number
US08299063B2

Reaction notes

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