Trifluoroacetic acid → 5,5-Dimethyl-1-(5-fluoro-2-methylphenyl)piperazin-2-one

HRID 1694944Notes

Reaction equation

HRID 1694944 reaction equation
FC(F)(F)C(O)=O.C(OC([N:15]1[CH2:20][C:19](=[O:21])[N:18]([C:22]2[CH:27]=[C:26]([F:28])[CH:25]=[CH:24][C:23]=2[CH3:29])[CH2:17][C:16]1([CH3:31])[CH3:30])=O)(C)(C)C>C(Cl)Cl>[CH3:30][C:16]1([CH3:31])[CH2:17][N:18]([C:22]2[CH:27]=[C:26]([F:28])[CH:25]=[CH:24][C:23]=2[CH3:29])[C:19](=[O:21])[CH2:20][NH:15]1

Participants

4

Reactant 2

HCID 6422Trifluoroacetic acidHCID 666457692,2-Dimethyl-4-(5-fluoro-2-methylphenyl)-5-oxopiperazine-1-carboxylic acid t-butyl ester

Product 1

HCID 666457455,5-Dimethyl-1-(5-fluoro-2-methylphenyl)piperazin-2-oneYield 86%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

10 ml of trifluoroacetic acid (134 mmol) was added to a solution of 4.5 g of 2,2-dimethyl-4-(5-fluoro-2-methylphenyl)-5-oxopiperazine-1-carboxylic acid t-butyl ester obtained in Example (70c) (13.4 mmol) in methylene chloride (20 ml) at room temperature, and the mixture was stirred at the same temperature for 30 minutes. The reaction mixture was concentrated under reduced pressure. A saturated sodium bicarbonate aqueous solution was added, followed by extraction with methylene chloride. Then, the organic layer was dried over anhydrous magnesium sulfate. After filtration, the solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (elution solvent:methylene chloride/methanol=10/1) to obtain 2.71 g of the title compound (yield: 86%).

Workup

  1. concentrationThe reaction mixture was concentrated under reduced pressure
  2. additionA saturated sodium bicarbonate aqueous solution was added
  3. extractionfollowed by extraction with methylene chloride
  4. dry with materialThen, the organic layer was dried over anhydrous magnesium sulfate
  5. filtrationAfter filtration
  6. customthe solvent was evaporated under reduced pressure
  7. customthe residue was purified by silica gel column chromatography (elution solvent:methylene chloride/methanol=10/1)

Sources & evidence

ORD record
ord-4dfe31eb0afa4ae9ae02824b57aa3051
Source dataset
uspto-grants-2012_04
Patent number
US08158790B2

Reaction notes

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