Ethylmorpholine → 1-[3(S)-[[N-(tert.butoxycarbonyl)-L-cysteinyl]amino]-2(R)-hydroxy-4-phenylbutyl]-N-tert.butyl-2(S)-piperidinecarboxamide

Participants

Reaction Steps

A solution of 1.02 g of 1-[3(S)-amino-2(R)-hydroxy-4-phenylbutyl]-N-tert.butyl-2(S)-piperidinecarboxamide and 685 mg of N-(tert.butoxycarbonyl)-S-methyl-L-cysteine in 7 ml of dry tetrahydrofuran was cooled in an ice/salt mixture. 394 mg of hydroxybenzotriazole, 335 mg of N-ethylmorpholine and 661 mg of dicyclohexylcarbodiimide were added and the mixture was stirred for 3 hours. The mixture was diluted with ethyl acetate and filtered. The filtrate was washed with aqueous sodium bicarbonate solution and with sodium chloride solution and then evaporated. The solvent was removed by evaporation and the residue was chromatographed on silica gel using dichloromethane/methanol (96:4) for the elution to give 630 mg of 1-[3(S)-[[N-(tert.butoxycarbonyl)-L-cysteinyl]amino]-2(R)-hydroxy-4-phenylbutyl]-N-tert.butyl-2(S)-piperidinecarboxamide in the form of a white solid; MS: m/e 565 [M+H]+.

Provenance & Evidence