4-Bromopyridinium chloride → tert-butyl 4-(1-(pyridin-4-yl)-1H-indol-6-yl)piperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

tert-Butyl 4-(1H-indol-6-yl)piperazine-1-carboxylate (500 mg, 1.66 mmol), sodium tert-butoxide (447 mg, 4.65 mmol), 4-bromopyridine hydrochloride (355 mg, 1.83 mmol) and toluene (11 mL) were sequentially acted to a reactor. Then, the gas dissolved in the mixture was removed using ultrasonic waves and nitrogen gas. After adding 10% (w/w) palladium-carbon (Pd—C, 177 mg, 0.083 mmol) and 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP; 52 mg, 0.083 mmol), the mixture was stirred at 100° C. for 24 hours in a sealed state. After cooling to room temperature and filtering using a diatomite pad, water was added and the mixture was extracted with ethyl acetate. The collected organic layer was washed with brine and concentrated under reduced pressure by drying with anhydrous sodium sulfate. The residue was purified by chromatography (silica gel, EA:Hx=1:1→EA only). The target compound (369 mg, 59%) was obtained as white solid.

Provenance & Evidence