Sodium Bicarbonate → 4-((S)-4-Benzyloxy-2-tert-butoxycarbonylamino-butyryl)-piperazine-1-carboxylic acid butyl ester

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Reaction Steps

To a solution of 5 g of (S)-4-Benzyloxy-2-tert-butoxycarbonylamino-butyric acid, 7.4 g of NEM and 5.3 g of TOTU in 35 ml of DMF, 4.8 g of Piperazine-1-carboxylic acid butyl ester trifluoroacetate was added at RT and stirred for 16 h. The reaction mixture was diluted saturated aqueous sodium hydrogen carbonate solution and extracted with 250 ml of ethyl acetate. The organic phase was dried over MgSO4 and the solvents were removed under reduced pressure. The crude product was purified by chromatography on silica gel eluting with a gradient of n-heptane/ethyl acetate. The fractions containing the product were combined and the solvent evaporated under reduced pressure. Yield: 6.3 g.

Provenance & Evidence