1-Methyl-3-phenylpiperazin-2-one → 1-Methyl-3-phenylpiperazine

HRID 1824453Notes

Reaction equation

HRID 1824453 reaction equation
[H-].[Al+3].[Li+].[H-].[H-].[H-].[CH3:7][N:8]1[CH2:13][CH2:12][NH:11][CH:10]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)[C:9]1=O>O1CCCC1>[CH3:7][N:8]1[CH2:13][CH2:12][NH:11][CH:10]([C:14]2[CH:15]=[CH:16][CH:17]=[CH:18][CH:19]=2)[CH2:9]1

Participants

4

Reactant 2

HCID 112869601-Methyl-3-phenylpiperazin-2-oneHCID 21226445Aluminium lithium hydride

Product 1

HCID 27600091-Methyl-3-phenylpiperazineYield 81.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
5 °C

Procedure

Lithium aluminium hydride (3.04 g, 0.8 moles) was suspended in tetrahydrofuran (60 ml) under nitrogen atmosphere. A solution of 1-methyl-2-oxo-3-phenylpiperazine (10 g in 10 ml of tetrahydrofuran) was added at 10–15° C. Slowly, raised the temperature of reaction mass and refluxed for 2 hours. Cooled the reaction mass to 5° C. and quenched successively with 3 ml of water, 3 ml of 15% aqueous sodium hydroxide solution and 9 ml of water. Reaction mass was stirred for 1 hour at 25–30° C. Filtered the reaction mass and the filtrate was concentrated under reduced pressure. Dissolved the residue in DM water (25 ml) and concentrated hydrochloric acid (8 ml) and the solution was washed with cyclohexane (20 ml). pH was adjusted to 11.0–12.0 with 50% w/w aqueous sodium hydroxide solution and extracted the product with methylene chloride (2×50 ml). Methylene chloride layer was concentrated under reduced pressure and 7.54 g of pure 1-Methyl-3-phenylpiperazine was isolated in cyclohexane having HPLC purity 99.7%.

Workup

  1. temperatureSlowly, raised
  2. customthe temperature of reaction mass
  3. temperaturerefluxed for 2 hours
  4. customquenched successively with 3 ml of water, 3 ml of 15% aqueous sodium hydroxide solution and 9 ml of water
  5. customReaction mass
  6. filtrationFiltered the reaction mass
  7. concentrationthe filtrate was concentrated under reduced pressure
  8. dissolutionDissolved the residue in DM water (25 ml) and concentrated hydrochloric acid (8 ml)
  9. washthe solution was washed with cyclohexane (20 ml)
  10. extractionextracted the product with methylene chloride (2×50 ml)
  11. concentrationMethylene chloride layer was concentrated under reduced pressure

Sources & evidence

ORD record
ord-69a0ef38b5a84710abe55767a2a4ecc7
Source dataset
uspto-grants-2006_05
Patent number
US07041826B2

Reaction notes

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