Reaktion #1272642

Reaktionsgleichung

(S)-2-Benzyloxycarbonylamino-pentanedioic acid 5-tert-butyl ester

TOTU

Piperazine-1-carboxylic acid butyl ester trifluoroacetate

→

4-((S)-2-Benzyloxycarbonylamino-4-tert-butoxycarbonyl-butyryl)-piperazine-1-carboxylic acid butyl ester

Lösungsmittel

DMF

sodium hydrogen carbonate

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted with 300 ml of ethyl acetate
2. 2
   WaschenThe organic phase was washed with diluted saturated aqueous sodium hydrogen carbonate solution
3. 3
   Trocknendried over MgSO4
4. 4
   SonstigeThe solvents were removed under reduced pressure
5. 5
   SonstigeThe crude product was purified by chromatography on silica gel eluting with n-heptane/ethyl acetate (1/1)
6. 6
   workup.ADDITIONThe fractions containing the product
7. 7
   Sonstigethe solvent evaporated under reduced pressure

Vorschrift

To a solution of 22.4 g of (S)-2-Benzyloxycarbonylamino-pentanedioic acid 5-tert-butyl ester, 30.7 g of NEM and 21.8 g of TOTU in 75 ml of DMF, 20 g of Piperazine-1-carboxylic acid butyl ester trifluoroacetate was added at RT and stirred for 16 h. The reaction mixture was then diluted with saturated aqueous sodium hydrogen carbonate solution and then extracted with 300 ml of ethyl acetate. The organic phase was washed with diluted saturated aqueous sodium hydrogen carbonate solution and dried over MgSO4. The solvents were removed under reduced pressure. The crude product was purified by chromatography on silica gel eluting with n-heptane/ethyl acetate (1/1). The fractions containing the product were combined and the solvent evaporated under reduced pressure. Yield: 33.4 g.

Quelle