Benzyl chloroformate → Benzyloxycarbonyl-L-proline

HRID 620917Notes

Reaction equation

HRID 620917 reaction equation
[NH:1]1[CH2:8][CH2:7][CH2:6][C@H:2]1[C:3]([OH:5])=[O:4].[OH-].[Na+].[CH2:11]([O:18][C:19](Cl)=[O:20])[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1>O>[C:19]([N:1]1[CH2:8][CH2:7][CH2:6][C@H:2]1[C:3]([OH:5])=[O:4])([O:18][CH2:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)=[O:20]

Participants

5

Reactant 3

HCID 10387Benzyl chloroformateHCID 14798Sodium Hydroxide2×HCID 145742L-Proline

Product 1

HCID 101987Benzyloxycarbonyl-L-prolineYield 96%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

To a solution of (S)-proline (25 g:0.22 mole) and sodium hydroxide (8.7 g:0.22 mole) in 150 ml of water was slowly added a solution of benzylchloroformate (43.5 g:0.26 mole) and sodium hydroxide (11.6 g:0.29 mole) in 75 ml of water with stirring under cooling on ice over 30 minutes, followed by continuing the stirring at the same temperature for 15 minutes. From the reaction mixture, excess benzylchloroformate was removed by extraction with 150 ml of chloroform. The aqueous layer was acidified with 5N hydrochloric acid, and the resulting oily product was extracted with chloroform. After drying the chloroform layer over magnesium sulfate, chloroform was removed by evaporation to give 52.2 g of (S)-1-carbobenzoxypyrrolidine-2-carboxylic acid as oil. Yield: 96%.

Workup

  1. temperatureunder cooling on ice over 30 minutes
  2. customfor 15 minutes
  3. customFrom the reaction mixture, excess benzylchloroformate was removed by extraction with 150 ml of chloroform
  4. extractionthe resulting oily product was extracted with chloroform
  5. dry with materialAfter drying the chloroform layer over magnesium sulfate, chloroform
  6. customwas removed by evaporation

Sources & evidence

ORD record
ord-d8a2efce942e4edd82c650ffe615ae23
Source dataset
uspto-grants-1989_04
Patent number
US04822892

Reaction notes

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