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

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Reaction Steps

To a solution of 3.5 g 4-{2-[(5-Hydroxy-1-phenyl-1H-pyrazole-3-carbonyl)-amino]-acetyl}-piperazine-1-carboxylic acid butyl ester in 23 ml DMF were added 1.87 g benzyl bromoacetate and 5.31 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: 3.6 g

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