4-Toluenesulfonyl chloride → 1,4-Di(tert-butoxycarbonyl)-2-(2-tosyloxyethyl)piperazine

Participants

Reaction Conditions

Reaction Steps

A solution of 1,4-di(tert-butoxycarbonyl)-2-(2-hydroxyethyl)piperazine (5.05 g) and p-toluenesulfonyl chloride (4.34 g) in methylene chloride (200 ml) was cooled to 0° C., followed by the dropwise addition of triethylamine (11 ml). The resulting mixture was stirred at 0° C. for 1 hour and at room temperature for 1 day. The reaction mixture was concentrated under reduced pressure. After dilution with ethyl acetate, the residue was washed with 1N hydrochloric acid, water and saturated aqueous NaCl solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified by flash column chromatography (ethyl acetate/hexane=1/4 to 1/1) using, as a carrier, silica gel, whereby the title compound (4.82 g) was obtained as a colorless solid.

Provenance & Evidence