L-Alanine → L-alanine ethyl ester 4-ethylbenzenesulfonate

HRID 1271653

Reaction equation

HRID 1271653 reaction equation
[NH2:1][C@H:2]([C:4]([OH:6])=[O:5])[CH3:3].[CH2:7]([C:9]1[CH:14]=[CH:13][C:12]([S:15]([OH:18])(=[O:17])=[O:16])=[CH:11][CH:10]=1)[CH3:8]>C(O)C>[CH2:7]([C:9]1[CH:10]=[CH:11][C:12]([S:15]([OH:18])(=[O:16])=[O:17])=[CH:13][CH:14]=1)[CH3:8].[CH2:7]([O:5][C:4](=[O:6])[C@H:2]([CH3:3])[NH2:1])[CH3:8]

Participants

4

Reactant 2

HCID 5950L-AlanineHCID 74024-Ethylbenzenesulfonic acid

Product 1

HCID 10357619L-alanine ethyl ester 4-ethylbenzenesulfonateYield 97.3%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Procedure

L-alanine (1.50 g, 16.84 mmol) and 4-ethylbenzenesulfonic acid (4-EBS) (3.76 g, 20.20 mmol) were added to ethanol (15 ml), and the mixture was heated overnight at 70 EC to perform esterification. To complete the esterification reaction, the mixture was heated to 90 EC, and ethanol (200 ml) was added over 3.5 hours, while distilling away almost the same amount of ethanol. Thereafter, the solvent was evaporated under reduced pressure, and the residue was dried under reduced pressure. The obtained oily residue was cooled in a refrigerator to allow partial crystallization. Diethyl ether (5 ml) and ethyl acetate (5 ml) were added, the residue was completely dissolved at 40° C., and the mixture was stirred at room temperature. Since crystallization occurred when a vessel containing the reaction solution was immersed in ice water, ethyl acetate (15 ml) was further added, and the mixture was stirred at room temperature to give a slurry. This slurry was cooled overnight in a refrigerator, and the crystals were separated and dried to give 2.98 g of L-alanine ethyl ester 4-ethylbenzenesulfonate (L-Ala-OEt 4-EBS salt) dry crystals (L-Ala-OEt 4-EBS salt content 98.5%, 9.67 mmol, yield 57.4%).

Workup

  1. temperaturethe mixture was heated overnight at 70 EC
  2. customthe esterification reaction
  3. additionwas added over 3.5 hours
  4. distillationwhile distilling away almost the same amount of ethanol
  5. customThereafter, the solvent was evaporated under reduced pressure
  6. customthe residue was dried under reduced pressure
  7. temperatureThe obtained oily residue was cooled in a refrigerator
  8. customcrystallization
  9. additionDiethyl ether (5 ml) and ethyl acetate (5 ml) were added
  10. dissolutionthe residue was completely dissolved at 40° C.
  11. customSince crystallization
  12. additioncontaining the reaction solution
  13. additionethyl acetate (15 ml) was further added
  14. stirringthe mixture was stirred at room temperature
  15. customto give a slurry
  16. temperatureThis slurry was cooled overnight in a refrigerator
  17. customthe crystals were separated
  18. customdried

Sources & evidence

ORD record
ord-d78ef16b578a44ccaba6617ff72056db
Source dataset
uspto-grants-2007_04
Patent number
US07205433B2

Linked notes

Loading…