Triethylamine → 4-(3-{(R)-3-[(S)-2-tert-butoxycarbonyl-1-(4-hydroxy-phenyl)-ethylcarbamoyl]-piperidin-1-yl}-3-oxo-propyl)-piperidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

214.0 mg (0.90 mmol) (S)-3-amino-3-(4-hydroxy-phenyl)-propionic acid tert-butyl ester were dissolved in 3.5 ml N,N-dimethylformamide and cooled to 0° C. To this solution was added a solution of 466.4 mg (1.00 mmol) tert-butyl 4-{3-[(3R)-3-{[(2,5-dioxopyrrolidin-1-yl)oxy]carbonyl}piperidin-1-yl]-3-oxopropyl}piperidine-1-carboxylate (example 5c) and 0.38 ml (2.71 mmol) triethylamine in 3.5 ml dichloromethane. The mixture was kept at 6° C. for 20 hours. Saturated ammonium chloride solution was added and the mixture extracted with dichloromethane. The organic layer was dried over sodium sulfate and concentrated in vacuum to give 820 mg. Chromatography over 5 g silica gel (dichloromethane/ethanol 100/0-95/5-90/10) gave 539 mg (102%) 4-(3-{(R)-3-[(S)-2-tert-butoxycarbonyl-1-(4-hydroxy-phenyl)-ethylcarbamoyl]-piperidin-1-yl}-3-oxo-propyl)-piperidine-1-carboxylic acid tert-butyl ester

Provenance & Evidence