Benzaldehyde → methyl (S)-N-tert-butoxycarbonyl-4-(alpha-hydroxybenzyl)pyroglutamate

HRID 1493381Notes

Reaction equation

HRID 1493381 reaction equation
C(NC(C)C)(C)C.C([Li])CCC.CCCCCC.[C:19]([O:23][C:24]([N:26]1[C:30](=[O:31])[CH2:29][CH2:28][C@H:27]1[C:32]([O:34][CH3:35])=[O:33])=[O:25])([CH3:22])([CH3:21])[CH3:20].[CH:36](=[O:43])[C:37]1[CH:42]=[CH:41][CH:40]=[CH:39][CH:38]=1>O1CCCC1.[Cl-].[NH4+]>[C:19]([O:23][C:24]([N:26]1[C:30](=[O:31])[CH:29]([CH:36]([OH:43])[C:37]2[CH:42]=[CH:41][CH:40]=[CH:39][CH:38]=2)[CH2:28][C@H:27]1[C:32]([O:34][CH3:35])=[O:33])=[O:25])([CH3:22])([CH3:21])[CH3:20]

Participants

7

Reactant 4

HCID 240BenzaldehydeHCID 7912DiisopropylamineHCID 108684851-O-tert-butyl 2-O-methyl (2S)-5-oxopyrrolidine-1,2-dicarboxylateHCID 178418244HCID 178418244, compound

Product 1

HCID 15092433methyl (S)-N-tert-butoxycarbonyl-4-(alpha-hydroxybenzyl)pyroglutamateYield 65%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent3×HCID 25517Ammonium ChlorideSolvent

Conditions

Temperature
-78 °C

Procedure

To 40 ml of tetrahydrofuran were added 1.54 ml (11 m mol) of diisopropylamine and 6.9 ml of 1.6M butyllithium-hexane solution, followed by stirring for 10 minutes under a stream of nitrogen. A solution of 2.43 g of methyl (S)-N-tert-butoxycarbonylpyroglutamate in 15 ml of tetrahydrofuran, was added and stirred for 10 minutes at -78° C. and further for 20 minutes at -40° C. To the reaction mixture which was again cooled to -78° C. was added dropwise a solution of 1.12 ml (11 m mol) of benzaldehyde in 4 ml of tetrahydrofuran. After stirring for 10 minutes, the reaction mixture was diluted with a saturated ammonium chloride solution, stirred until the temperature of the mixture reached room temperature and extracted with ethyl acetate. The combined organic layers were washed with water and then a saturated saline solution, dried over sodium sulfate and distilled to remove the solvent. The residue was subjected to a silica gel column (2.5×40 cm) chromatography (developed by ethyl acetate-hexane=1:3→1:2→1:1) to obtain 2.26 g (65%) of methyl (S)-N-tert-butoxycarbonyl-4-(α-hydroxybenzyl)pyroglutamate as colorless oil.

Workup

  1. stirringstirred for 10 minutes at -78° C. and further for 20 minutes at -40° C
  2. stirringAfter stirring for 10 minutes
  3. stirringstirred until the temperature of the mixture
  4. customreached room temperature
  5. extractionextracted with ethyl acetate
  6. washThe combined organic layers were washed with water
  7. dry with materiala saturated saline solution, dried over sodium sulfate
  8. distillationdistilled
  9. customto remove the solvent

Sources & evidence

ORD record
ord-0dabdf408bd743ce857d96c548eb1d8a
Source dataset
uspto-grants-1991_06
Patent number
US05021439

Reaction notes

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