Sodium sulfate decahydrate → (S)-2-Phenethylpiperazine

HRID 1350355Notes

Reaction equation

HRID 1350355 reaction equation
[CH2:1]([C@@H:9]1[NH:14][C:13](=O)[CH2:12][NH:11][C:10]1=O)[CH2:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1.[H-].[Al+3].[Li+].[H-].[H-].[H-].O.O.O.O.O.O.O.O.O.O.S([O-])([O-])(=O)=O.[Na+].[Na+].[H][H]>C1COCC1>[CH2:1]([C@H:9]1[CH2:10][NH:11][CH2:12][CH2:13][NH:14]1)[CH2:2][C:3]1[CH:4]=[CH:5][CH:6]=[CH:7][CH:8]=1

Participants

6

Reactant 4

HCID 62649Sodium sulfate decahydrateHCID 148336803-(S)-phenethyl-piperazine-2,5-dioneHCID 21226445Aluminium lithium hydrideHCID 178418361HCID 178418361, compound

Product 1

HCID 44828673(S)-2-PhenethylpiperazineYield 90.8%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
0 °C

Procedure

Add 3-(S)-phenethyl-piperazine-2,5-dione (2.5 g, 11 mmol) portionwise to lithium aluminum hydride (1.75 g, 46 mmol) in THF (46 mL). Reflux the resulting suspension for an hour and cool to 0° C. Add sodium sulfate decahydrate carefully until hydrogen evolution ceases and stir the mixture for an additional three hours at room temperature and filter. Wash the solids with THF several times. Combine the filtrates, concentrate, and recrystallize the residue with THF/pentane to afford 2-(S)-phenethyl-piperazine as white crystals (1.9 g, 90%): mp 114–115° C.; 1H NMR (CDCl3): δ1.58–1,70 (m, 2H), 2.41 (dd, 1H), 2.58–3.02 (m, 8H), 7.16–7.30 (m, 5H); MS (APCI) m/z (rel intensity) 191 (100).

Workup

  1. temperatureReflux the resulting suspension for an hour
  2. filtrationfilter
  3. washWash the solids with THF several times
  4. concentrationCombine the filtrates, concentrate
  5. customrecrystallize the residue with THF/pentane

Sources & evidence

ORD record
ord-f8c5b92996a844679e249529204cfb48
Source dataset
uspto-grants-2007_05
Patent number
US07214673B2

Reaction notes

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