Triphenylphosphine → tert-butyl 4-{2-[3-(3,4-difluorophenyl)-2,2-dioxido-2,1,3-benzothiadiazol-1(3H)-yl]ethyl}piperazine-1-carboxylate

Participants

Reaction Steps

A solution of 1-(3,4-difluorophenyl)-1,3-dihydro-2,1,3-benzothiadiazole2,2-dioxide (0.29 g, 1.0 mmol) in tetrahydrofuran (10 mL) was cooled to 0° C., treated with triphenylphosphine (0.41 g, 1.5 mmol), tert-Butyl 4-(2-hydroxyethyl)piperazine-1-carboxylate (0.47 g, 2.1 mmol) were added followed by diisopropylazodicarboxylate (0.3 mL, 1.5 mmol). The reaction mixture stirred for 2 hours at ambient temperature and then was evaporated. The crude reaction product was purified by flash chromatography (SiO2, 3-70% ethyl acetate/hexane) to provide tert-butyl 4-{2-[3-(3,4-difluorophenyl)-2,2-dioxido-2,1,3-benzothiadiazol-1(3H)-yl]ethyl}piperazine-1-carboxylate (0.39 g, 76%) as a pink solid:

Provenance & Evidence