2-Benzylpyrazine → 2-Benzylpiperazine

HRID 344901Notes

Reaction equation

HRID 344901 reaction equation
[CH2:1]([C:8]1[CH:13]=[N:12][CH:11]=[CH:10][N:9]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1>C(O)(=O)C.[Pt](=O)=O>[CH2:1]([CH:8]1[CH2:13][NH:12][CH2:11][CH2:10][NH:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

4

Reactant 1

HCID 5203702-Benzylpyrazine

Product 1

HCID 5590332-BenzylpiperazineYield 64.2%

Reagents, catalysts & solvents 2

HCID 345198Adams' catalystCatalystHCID 176Acetic AcidSolvent

Conditions

Temperature
20 °C

Procedure

A solution of 2-benzylpyrazine (8 g) in acetic acid (60 cc) is treated with platinum dioxide (0.8 g) and hydrogenated under a pressure of 1 atmosphere at approximately 20° C. When the absorption of hydrogen is complete, the catalyst is removed by filtration through diatomaceous silica. The solution is concentrated to dryness under reduced pressure (20 kPa) at approximately 60° C. The dry extract is suspended in ethanol (40 cc) and treated at approximately 20° C. with a solution of sodium ethylate prepared from sodium (1.49 g) in ethanol (40 cc). After 2 hours' stirring at approximately 20° C., the suspension is concentrated to dryness under reduced pressure (20 kPa) at approximately 30° C. The dry extract is taken up with ethyl ether (60 cc). The insoluble matter is removed by filtration through diatomaceous silica. The filtrate is concentrated to dryness under reduced pressure under the same conditions as above. The dry extract is taken up with isopropyl ether (20 cc), drained and washed with the same solvent (2×5 cc). (RS)-2-Benzylpiperazine (5.32 g) is obtained in the form of a light beige solid, m.p. 90° C.

Workup

  1. customWhen the absorption of hydrogen
  2. customthe catalyst is removed by filtration through diatomaceous silica
  3. concentrationThe solution is concentrated to dryness under reduced pressure (20 kPa) at approximately 60° C
  4. extractionThe dry extract
  5. additiontreated at approximately 20° C. with a solution of sodium ethylate
  6. customprepared from sodium (1.49 g) in ethanol (40 cc)
  7. concentrationthe suspension is concentrated to dryness under reduced pressure (20 kPa) at approximately 30° C
  8. extractionThe dry extract
  9. customThe insoluble matter is removed by filtration through diatomaceous silica
  10. concentrationThe filtrate is concentrated to dryness under reduced pressure under the same conditions as above
  11. extractionThe dry extract
  12. washwashed with the same solvent (2×5 cc)

Sources & evidence

ORD record
ord-e8955fce54b2478a958998f1ac2765a1
Source dataset
uspto-grants-1991_10
Patent number
US05053509

Reaction notes

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