1-Piperazinecarboxylic acid, ethyl ester → 4-((S)-2-benzyloxycarbonylamino-3-tert-butoxycarbonyl-propionyl)-piperazine-1-carboxylic acid ethyl ester

Beteiligte Stoffe

Reaktionsschritte

To a solution of 25 g of (S)-2-Benzyloxycarbonylamino-succinic acid 4-tert-butyl ester, 35.6 g of NEM and 25.3 g of TOTU in 125 ml of DMF, 12.9 g of Piperazine-1-carboxylic acid ethyl ester was added at RT and stirred for 3 h. The reaction mixture was diluted saturated aqueous sodium hydrogen carbonate solution and extracted with 400 ml of ethyl acetate. The organic phase was washed with diluted saturated aqueous sodium hydrogen carbonate solution and dried over MgSO4 and 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: 35.4 g.

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