4-Nitrophenyl chloroformate → HCID 57918966, compound

Participants

Reaction Steps

To a stirred solution of crude (3S,4S)-4-amino-N-butyl-3-(tertbutyldimethylsilyloxy)-5-cyclohexylpentanamide (311 mg, 0.81 mmol) in MeCN were added powdered NaHCO3 (203 mg, 2.43 mmol) and p-nitrophenyl chloroformate (244 mg, 1.21 mmol) and the mixture was stirred overnight at rt. The mixture was concentrated under reduced pressure. The residue was taken up in 1:1 EtOAc/Et2O (90 mL), washed with water (20 mL) and brine (20 mL), dried over MgSO4 and concentrated to leave an orange oil. This material was chromatographed on a 40-g silica cartridge eluted with a 0 to 100% ethyl acetate in hexanes gradient to afford 4-nitrophenyl (2S,3S)-5-(butylamino)-3-(tert-butyldimethylsilyloxy)-1-cyclohexyl-5-oxopentan-2-ylcarbamate (39 mg, 8%).

Provenance & Evidence