Reaction #343674

Reaction equation

H-Gly-OEt.HCl

Boc-Val-OH

HOBT

WSC.HCl

→

Boc-Val-Gly-OEt

Yield 85.3%

Solvents

DMF

Conditions

Workup

1. 1
   ConcentrationThe reaction mixture was concentrated under reduced pressure
2. 2
   workup.DISSOLUTIONthe residue was dissolved in ethyl acetate
3. 3
   Washsuccessively washed three times with 1N hydrochloric acid
4. 4
   Dryingonce with saturated aqueous sodium chloride, three times with 5% aqueous sodium hydrogen carbonate, three times with saturated aqueous sodium chloride, and dried over anhydrous sodium sulfate
5. 5
   Concentrationfollowed by concentration under reduced pressure
6. 6
   OtherThe residue was recrystallized from ethyl acetate-n-hexane

Procedure

To a solution of 3.21 g of the H-Gly-OEt.HCl dissolved in 10 ml of DMF, under cooling at -5° C., 5.00 g of Boc-Val-OH, 3.10 g of HOBT and 4.79 g of WSC.HCl were added, and the mixture was stirred at -5° C. for one hour and at room temperature overnight. The reaction mixture was concentrated under reduced pressure, and the residue was dissolved in ethyl acetate, successively washed three times with 1N hydrochloric acid, once with saturated aqueous sodium chloride, three times with 5% aqueous sodium hydrogen carbonate, three times with saturated aqueous sodium chloride, and dried over anhydrous sodium sulfate, followed by concentration under reduced pressure. The residue was recrystallized from ethyl acetate-n-hexane to give 5.93 g (yield: 85.2%) of Boc-Val-Gly-OEt melting at 91.5° to 93° C.

Source