Water → 4-[2-(3-Methoxypropoxy)phenyl]-2,2-dimethylpiperazine-1-carboxylic acid t-butyl ester

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Reaction Steps

2.30 ml of a borane-tetrahydrofuran complex (1.2 mol/l) (2.76 mmol) was added to a solution of 303 mg of 4-[2-(3-methoxypropoxy)phenyl]-2,2-dimethyl-5-oxopiperazine-1-carboxylic acid t-butyl ester obtained in Example (10e) (0.77 mmol) in tetrahydrofuran (2.8 ml) under a nitrogen atmosphere and under ice-cooling over five minutes, and the mixture was stirred at room temperature for 15 minutes. The reaction mixture was cooled in an ice bath. Then, 2.76 ml of a 1 N sodium hydroxide aqueous solution (2.76 mmol) was slowly added and the mixture was further stirred at room temperature for one hour. Water was added to the reaction mixture, followed by extraction with ethyl acetate. Then, the organic layer was washed with water and brine and dried over anhydrous magnesium sulfate. After filtration, the solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (elution solvent:n-hexane/ethyl acetate=30/1-10/1) to obtain 276 mg of the title compound (yield: 91%).

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