Sodium Hydroxide → 2-Phenylpiperazine

HRID 482291Notes

Reaction equation

HRID 482291 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 gram, 74.53 mmol) in acetic acid (58.2 ml) was added palladium acetate Pd(OAc)2 (2.33 gram, 9.94 mmol). The mixture was hydrogenated at 50 psi for four hours. 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 gram). 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 mass [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-210730ed87c04929b52026db3f0c2c77
Source dataset
uspto-grants-1998_08
Patent number
US05795894

Reaction notes

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