Sodium Hydroxide → 2-Phenylpiperazine

HRID 443061Notes

Reaction equation

HRID 443061 reaction equation
[C:1]1([C:7]2[CH:12]=[N:11][CH:10]=[CH:9][N:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[OH-].[Na+]>C(O)(=O)C.O>[C:1]1([CH:7]2[CH2:12][NH:11][CH2:10][CH2:9][NH:8]2)[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1

Participants

5

Reactant 2

HCID 14798Sodium HydroxideHCID 642870Pyrazine, 2-phenyl-

Product 1

HCID 2506732-PhenylpiperazineYield 59.5%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Procedure

To a solution of 2-phenylpyrazine (11.64 g, 74.53 mmol) in acetic acid (58.2 mL) was added palladium acetate Pd(OAc)2 (2.33 g, 9.94 mmol). The mixture was hydrogenated at 50 psi for 4 h. After the reaction was complete, the catalyst was filtered off and rinsed with a small portion of acetic acid. The filtrate was concentrated under house vacuum to give a brown-black solid which was suspended in deionized water (300 mL) and adjusted to pH 13 with 20% NaOH solution. The product was extracted from aqueous solution with EtOAc (200 mL, 3×), dried over MgSO4, filtered and evaporated to dryness to give 2-phenylpiperazine (7.2 g). An additional 1.6 g of 2-phenylpiperazine was obtained by evaporating the aqueous fraction to a solid and triturating the solid with CH2Cl2. Total yield of 2-phenyl-piperazine was 73%. The crude material was crystallized from EtOAc and hexane for characterization, m.p. 86°-88° C.; FAB MS [M+1]+ 163;

Workup

  1. filtrationthe catalyst was filtered off
  2. washrinsed with a small portion of acetic acid
  3. concentrationThe filtrate was concentrated under house vacuum
  4. customto give a brown-black solid which
  5. extractionThe product was extracted from aqueous solution with EtOAc (200 mL, 3×)
  6. dry with materialdried over MgSO4
  7. filtrationfiltered
  8. customevaporated to dryness

Sources & evidence

ORD record
ord-f2c79ed541144f2f96a11b9c267a6001
Source dataset
uspto-grants-1999_04
Patent number
US05892039

Reaction notes

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