(R)-tert-butyl 4-benzyl-2-isopropyl-3-oxopiperazine-1-carboxylate → HCID 67492477, compound

HRID 1521479Notes

Reaction equation

HRID 1521479 reaction equation
C([N:8]1[CH2:13][CH2:12][N:11]([C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])[C@H:10]([CH:21]([CH3:23])[CH3:22])[C:9]1=[O:24])C1C=CC=CC=1>C1COCC1>[CH:21]([CH:10]1[C:9](=[O:24])[NH:8][CH2:13][CH2:12][N:11]1[C:14]([O:16][C:17]([CH3:19])([CH3:18])[CH3:20])=[O:15])([CH3:23])[CH3:22]

Participants

3

Reactant 1

HCID 89827913(R)-tert-butyl 4-benzyl-2-isopropyl-3-oxopiperazine-1-carboxylate

Product 1

HCID 67492477HCID 67492477, compoundYield 59%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a three-necked bottle containing THF (10 mL) was bubbled with NH3 (gas) at −78° C. for 5 mins. Na (300 mg, 13.0 mmol) was added to the mixture slowly at −78° C. After stirring for 30 min, (R)-tert-butyl 4-benzyl-2-isopropyl-3-oxopiperazine-1-carboxylate (700 mg, 2.11 mmol) was added dropwise at −78° C. The mixture was stirred at −78° C. for 30 min. The mixture was quenched with sat. aq NH4Cl (10 mL) and extracted with EtOAc (3×10 mL). The combined organic layers were washed with brine (10 mL), dried over anhydrous Na2SO4, filtered, concentrated and purified by preparative TLC with PE/EtOAc 1/1 to afford tert-butyl 2-isopropyl-3-oxopiperazine-1-carboxylate (300 mg, 59% yield) as a white solid. The product was found to be a racemic mixture. The cause of racemization was not investigated. LC-MS m/z 187.1 [M-56+H]+, 265.1 [M+Na]+. 1H NMR (CDCl3 400 MHz): δ 6.29 (s, 1H), 4.55-3.99 (m, 2H), 3.51-3.36 (m, 1H), 3.32-3.12 (m, 2H), 2.34-2.29 (m, 1H), 1.46 (s, 9H), 1.09 (d, J=6.8 Hz, 3H), 0.99 (d, J=7.2 Hz, 3H).

Workup

  1. customwas bubbled with NH3 (gas) at −78° C. for 5 mins
  2. stirringThe mixture was stirred at −78° C. for 30 min
  3. customThe mixture was quenched with sat. aq NH4Cl (10 mL)
  4. extractionextracted with EtOAc (3×10 mL)
  5. washThe combined organic layers were washed with brine (10 mL)
  6. dry with materialdried over anhydrous Na2SO4
  7. filtrationfiltered
  8. concentrationconcentrated
  9. custompurified by preparative TLC with PE/EtOAc 1/1

Sources & evidence

ORD record
ord-487a03f3fac5490a93720fe8b9fc7d3c
Source dataset
uspto-grants-2015_07
Patent number
US09073931B2

Reaction notes

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