L-Serine → N-(Benzyloxycarbonyl)-L-serine

HRID 1648499Notes

Reaction equation

HRID 1648499 reaction equation
[NH2:1][C@H:2]([C:5]([OH:7])=[O:6])[CH2:3][OH:4].[OH-].[Na+].Cl[C:11]([O:13][CH2:14][C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1)=[O:12]>O>[C:11]([NH:1][C@H:2]([C:5]([OH:7])=[O:6])[CH2:3][OH:4])([O:13][CH2:14][C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1)=[O:12]

Participants

5

Reactant 3

HCID 5951L-SerineHCID 10387Benzyl chloroformateHCID 14798Sodium Hydroxide2×

Product 1

HCID 100310N-(Benzyloxycarbonyl)-L-serine

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
25 °C

Procedure

L-Serine (20.00 g, 190.3 mmol) was dissolved in water, and aqueous sodium hydroxide was added to adjust the pH of the solution to about 8.5 while maintaining the temperature at about 25° C. Benzyl chloroformate (36.0 g, 211.0 mmol) was added while maintaining the pH between 8.3 and 8.5 by the addition of aqueous sodium hydroxide and the temperature was maintained at about 30° C. The mixture was stirred for about 2 hours. The reaction mixture was extracted with methylene chloride. The phases were separated, and the pH of the aqueous phase was adjusted to about 7 with concentrated hydrochloric acid. The aqueous phase was heated to about 40° C. under low vacuum to remove any residual methylene chloride. Water was added and the aqueous solution was heated to about 60° C. The pH was adjusted to about 2 with concentrated hydrochloric acid while maintaining the temperature at about 60° C. The solution was cooled to about 50° C. while stirring and seed crystals were added with stirring, cooling was continued to about 0° C. to complete the crystallization. The product was collected and the cake was washed with cold (about 5° C.) water. The product was dried under vacuum at about 40° C. to afford carbobenzyloxy-L-serine.

Workup

  1. temperaturewhile maintaining the pH between 8.3 and 8.5
  2. temperaturethe temperature was maintained at about 30° C
  3. extractionThe reaction mixture was extracted with methylene chloride
  4. customThe phases were separated
  5. temperatureThe aqueous phase was heated to about 40° C. under low vacuum
  6. customto remove any residual methylene chloride
  7. additionWater was added
  8. temperaturethe aqueous solution was heated to about 60° C
  9. temperaturewhile maintaining the temperature at about 60° C
  10. temperatureThe solution was cooled to about 50° C.
  11. stirringwhile stirring
  12. additionseed crystals were added
  13. stirringwith stirring
  14. temperaturecooling
  15. customwas continued to about 0° C.
  16. customthe crystallization
  17. customThe product was collected
  18. washthe cake was washed with cold (about 5° C.) water
  19. customThe product was dried under vacuum at about 40° C.

Sources & evidence

ORD record
ord-567d20d746a240218fd4573585c5c327
Source dataset
uspto-grants-1995_07
Patent number
US05436347

Reaction notes

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