L-Glutamine → HCID 13819651, compound

Participants

Reaction Conditions

Reaction Steps

H-Gln-OH (2 eq.) and NaHCO3 (2 eq.) were dissolved under stirring in water at maximum 45° C. and then cooled to about 5° C. Z-Val-OSu (1 eq.) was dissolved in MeCN and added in the aqueous solution in such way that the temperature did not rise above 10° C. The mixture was stirred for at least 1 h at ±5° C. before being warmed to room temperature for at least two hours. The peptide solution was concentrated under vacuum, diluted with water and washed twice with AcOEt. The aqueous phase was then diluted with i-BuOH and the pH was adjusted to 2.5 with a solution of KHSO4. DCM was then added to extract the peptide into the organic phase which was washed with a 5% weight NaCl solution and finally with water. The organic phase was collected and concentrated under reduced pressure until water content in the evaporates was <1% weight. The concentrate was diluted with hot isopropyl acetate and left to cool to 25° C. under gentle stirring to crystallize the peptide. The solid was recovered by filtration, once washed with AcOiPr at 25° C. and dried under vacuum until AcOiPr content in the peptide was ≦5% weight. After drying under vacuum not less than 70% of Z-Val-Gln-OH was recovered.

Provenance & Evidence