Cesium carbonate → 4-(2-{[5-((R)-1-Benzyloxycarbonyl-ethoxy)-1-phenyl-1H-pyrazole-3-carbonyl]-amino}-acetyl)-piperazine-1-carboxylic acid butyl ester

Beteiligte Stoffe

Reaktionsschritte

To a solution of 1.75 g 4-{2-[(5-Hydroxy-1-phenyl-1H-pyrazole-3-carbonyl)-amino]-acetyl}-piperazine-1-carboxylic acid butyl ester in 10 ml DMF were added 990 mg (S)-2-bromo-propionic acid benzyl ester (prepared by standard benzylation procedure using (S)-2-bromopropionic acid and benzyl alcohol/p-TsOH) and 2.67 g cesium carbonate. After stirring at room temperature for 12 h the solution was diluted with 100 ml ethyl acetate and extracted with aqueous LiCl (4% w/w), 0.1 M HCl and aqueous NaHCO3. The crude product obtained after evaporation of the solvent was pure enough for the following reactions. Yield: 2.1 g

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