Cesium carbonate → 4-[2-(2,4-Bis-benzyloxy-5-chloro-phenyl)-2-oxo-ethyl]-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

Cesium carbonate (2.95 g, 9 mmol) was added in three portions to a stirred solution of 1-(2,4-Bis-benzyloxy-5-chloro-phenyl)-2-bromo-ethanone (4.4 g, 9 mmol) and piperazine-1-carboxylic acid tert-butyl ester (1.74 g, 9 mmol) in dimethylformamide (20 ml). The suspension was stirred for 2 h then partitioned between water (200 ml) and ethyl acetate (3×50 ml). The combined organic extracts were washed with water (100 ml), dried over magnesium sulphate and concentrated to give 4-[2-(2,4-Bis-benzyloxy-5-chloro-phenyl)-2-oxo-ethyl]-piperazine-1-carboxylic acid tert-butyl ester as a yellow oil (4 g)

Provenance & Evidence