Diethyl Ether → benzyl (2S)-N-tert-butoxycarbonylamino-5-oxohexanoate

HRID 1372776Notes

Reaction equation

HRID 1372776 reaction equation
[C:1]([O:5][C:6]([N:8]1[C:12](=[O:13])[CH2:11][CH2:10][C@H:9]1[C:14]([O:16][CH2:17][C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)=[O:15])=[O:7])([CH3:4])([CH3:3])[CH3:2].C[Li].[CH3:26]COCC.[Cl-].[NH4+]>C1COCC1>[C:1]([O:5][C:6]([NH:8][C@@H:9]([CH2:10][CH2:11][C:12](=[O:13])[CH3:26])[C:14]([O:16][CH2:17][C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)=[O:15])=[O:7])([CH3:4])([CH3:3])[CH3:2]

Participants

6

Reactant 4

HCID 3283Diethyl EtherHCID 25517Ammonium ChlorideHCID 80274822-Benzyl 1-tert-butyl (2S)-5-oxopyrrolidine-1,2-dicarboxylateHCID 178418348HCID 178418348, compound

Product 1

HCID 13893427benzyl (2S)-N-tert-butoxycarbonylamino-5-oxohexanoateYield 39%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Benzyl N-tert-butoxycarbonyl-(2S)-pyroglutamate (20.5 g, 64.2 mmol) was dissolved in THF (500 ml). Methyl lithium (a 1.04M ether solution, 61.7 ml, 64.2 mmol) was added dropwise at −78° C. The temperature of the reaction mixture was caused to rise back gradually to room temperature under stirring, and the resulting mixture was stirred for 18 hours. A saturated aqueous solution of ammonium chloride was added and the resulting mixture was concentrated under reduced pressure. The concentrate was extracted with ether. The extract was washed with saturated brine, dried over anhydrous sodium sulfate, and distilled under reduced pressure to remove the solvent. The residue was purified by chromatography on a silica gel column, whereby from hexane/ethyl acetate (3/1) eluate fractions, benzyl (2S)-N-tert-butoxycarbonylamino-5-oxohexanoate (8.37 g, 39%) was obtained as a yellow oil.

Workup

  1. customto rise back gradually to room temperature
  2. stirringthe resulting mixture was stirred for 18 hours
  3. concentrationthe resulting mixture was concentrated under reduced pressure
  4. extractionThe concentrate was extracted with ether
  5. washThe extract was washed with saturated brine
  6. dry with materialdried over anhydrous sodium sulfate
  7. distillationdistilled under reduced pressure
  8. customto remove the solvent
  9. customThe residue was purified by chromatography on a silica gel column, whereby from hexane/ethyl acetate (3/1) eluate fractions

Sources & evidence

ORD record
ord-897313a1a0a740cf821e0cd452127af5
Source dataset
uspto-grants-2007_01
Patent number
US07157487B2

Reaction notes

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