Trifluoromethanesulfonic anhydride → 5-Bromo-2-pentyl-3,4-dihydroisoquinolin-1(2H)-one

Participants

Reaction Conditions

Reaction Steps

5.44 g of methyl[2-(2-bromophenyl)ethyl]pentylcarbamate are dissolved, under an inert atmosphere, in 200 cm3 of dichloromethane at a temperature close to 20° C. 6.07 g of 4-dimethylaminopyridine are added to the reaction mixture. It is cooled to a temperature in the vicinity of 0° C. 13.94 cm3 of trifluoromethanesulfonic anhydride are poured into the reaction mixture over 15 min. The suspension is kept stirring for 4 h at a temperature close to 20° C. Dichloromethane and also 50 cm3 of a water/ice mixture are added to the reaction medium. The 4-dimethylaminopyridine is filtered. The filtrate is decanted, the aqueous phase is extracted with dichloromethane. The organic phases are combined, washed with a saturated aqueous solution of sodium chloride, dried over magnesium sulfate and concentrated using a rotary evaporator under reduced pressure (5 kPa). The crude product obtained is purified by flash chromatography over silica (column: 200 g; particle size: 15-40 μm; eluent: 90% dichloromethane/10% ethyl acetate). After concentrating the fractions under reduced pressure, 4.14 g of 5-bromo-2-pentyl-3,4-dihydroisoquinolin-1(2H)-one are obtained in the form of a colorless oil.

Provenance & Evidence