p-Bromobenzenesulfonyl chloride → 4-(4-BOC-piperazinosulfonyl)bromobenzene

Participants

Reaction Steps

Triethylamine (0.94 mL, 6.71 mmol) was added to a stirred reaction mixture of N-tert-butoxycarbonyl piperazine (0.50 g, 2.68 mmol) in tetrahydrofuran (6 mL) at 0° C., then the reaction mixture was stirred at room temperature for 15 minutes. A solution of 4-bromo-benzenesulfonyl chloride (0.686 g, 2.68 mmol) in tetrahydrofuran (4 mL) was added to the reaction mixture and stirring continued for another 2 hours. Tetrahydrofuran was evaporated off under reduced pressure, then the reaction mixture was diluted with ethyl acetate (20 mL). The inorganic materials were filtered off through a celite bed. The filtrate was washed with 2 N aqueous HCl (5 mL), dried over anhydrous sodium sulfate and concentrated in vacuo to yield 1.00 g (92%) of 4-(4-bromo-benzenesulfonyl)-piperazine-1-carboxylic acid tert-butyl ester as a white solid, which was used in the next step without further purification. MS cald. for C15H21BrN2O4S [(M+NH4)+] 422, obsd. 422.1.

Provenance & Evidence