1,1-Dimethylethyl (2S)-4-{[4-(acetylamino)-2-methylphenyl]methyl}-2-methyl-1-piperazinecarboxylate → tert-butyl (2S)-4-[(4-amino-2-methylphenyl)methyl]-2-methylpiperazine-1-carboxylate

HRID 644732Notes

Reaction equation

HRID 644732 reaction equation
C([NH:4][C:5]1[CH:10]=[CH:9][C:8]([CH2:11][N:12]2[CH2:17][CH2:16][N:15]([C:18]([O:20][C:21]([CH3:24])([CH3:23])[CH3:22])=[O:19])[C@@H:14]([CH3:25])[CH2:13]2)=[C:7]([CH3:26])[CH:6]=1)(=O)C>[OH-].[K+].CO>[NH2:4][C:5]1[CH:10]=[CH:9][C:8]([CH2:11][N:12]2[CH2:17][CH2:16][N:15]([C:18]([O:20][C:21]([CH3:23])([CH3:22])[CH3:24])=[O:19])[C@@H:14]([CH3:25])[CH2:13]2)=[C:7]([CH3:26])[CH:6]=1

Participants

4

Reactant 1

HCID 592621441,1-Dimethylethyl (2S)-4-{[4-(acetylamino)-2-methylphenyl]methyl}-2-methyl-1-piperazinecarboxylate

Product 1

HCID 59262126tert-butyl (2S)-4-[(4-amino-2-methylphenyl)methyl]-2-methylpiperazine-1-carboxylateYield 49.9%

Reagents, catalysts & solvents 2

HCID 887MethanolSolvent2×HCID 14797Potassium HydroxideSolvent

Conditions

Temperature
130 °C

Procedure

1,1-Dimethylethyl (2S)-4-{[4-(acetylamino)-2-methylphenyl]methyl}-2-methyl-1-piperazinecarboxylate (D79) (497 mg, 1.4 mmol) in KOH (1M aq soln., 5 mL) and methanol (5 mL) was heated to 140° C. for 1 h in a microwave reactor. The reaction mixture was diluted with methanol (5 mL) and heated for a total of 4 h 55 minutes at 130° C. in the microwave. The reaction mixture was concentrated to remove the methanol and partitioned between DCM and water. The organic layer was dried and concentrated to give the crude product which was purified by chromatography. Elution with 0-100% diethyl ether/petroleum ether followed by a column flush with 10% (2M NH3 in methanol) in DCM yielded the title compound as a yellow oil (223 mg). δH (CDCl3, 400 MHz) 6.97 (1H, d), 6.52 (1H, d), 6.46 (1H, dd), 4.17 (1H, br.s), 3.76 (1H, d), 3.57 (2H, br.s), 3.29 (2H, m), 3.01 (1H, td), 2.70 (1H, d), 2.56 (1H, d), 2.30 (3H, s), 2.10 (1H, dd), 1.90 (1H, m), 1.45 (9H, s), 1.18 (3H, d). MS (AP+): MNa+ 342.3 (MNa+), no molecular ion (MH+) observed.

Workup

  1. concentrationThe reaction mixture was concentrated
  2. customto remove the methanol
  3. custompartitioned between DCM and water
  4. customThe organic layer was dried
  5. concentrationconcentrated
  6. customto give the crude product which
  7. customwas purified by chromatography
  8. washElution with 0-100% diethyl ether/petroleum ether
  9. customflush with 10% (2M NH3 in methanol) in DCM

Sources & evidence

ORD record
ord-bb4b6e1e58cc4f54a97fa038f339865c
Source dataset
uspto-grants-2010_04
Patent number
US07700599B2

Reaction notes

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