Water → tert-butyl [(3S)-3-hydroxy-4-oxo-4-((5-(tritylamino)-1-[2-(trityloxy)ethyl]-1H-pyrazol-4-yl)amino)butyl]carbamate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of tert-butyl ((3S)-3-hydroxy-4-{[1-(2-hydroxyethyl)-5-(tritylamino)-1H-pyrazol-4-yl]amino}-4-oxobutyl)carbamate (2.5 g) in N,N-dimethylformamide (25 ml) were added trityl chloride (1.25 g), triethylamine (1.78 ml) and 4-dimethylaminopyridine (52.1 mg), and the mixture was stirred for 1 hour. The reaction mixture was warmed up to 60° C. and stirred at the same temperature for 2 days. Water was added to the mixture, and the whole mixture was extracted with ethyl acetate. The extract was washed with water and brine and dried over anhydrous magnesium sulfate. Concentration under reduced pressure gave an oil, which was purified by column chromatography on silica gel (methylene chloride:ethyl acetate=5:1) to give tert-butyl [(3S)-3-hydroxy-4-oxo-4-({5-(tritylamino)-1-[2-(trityloxy)ethyl]-1H-pyrazol-4-yl}amino)butyl]carbamate (1.5 g).

Provenance & Evidence