Ammonium Chloride → 2-Benzyl-5-bromo-3,4-dihydroisoquinolin-1(2H)-one

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Reaction Steps

0.5 g of methyl benzyl[2-(2-bromophenyl)ethyl]carbamate is dissolved under an inert atmosphere in 20 cm3 of dichloromethane at a temperature close to 20° C. 0.526 g of N,N-dimethylpyridin-4-amine is added, then the reaction mixture is cooled to a temperature close to 0° C. 1.2 cm3 of trifluoromethanesulfonic anhydride is introduced dropwise. The suspension obtained is stirred for 15 min at a temperature close to 0° C., then for 4 h 30 min while allowing it to gradually climb back up to a temperature close to 20° C. Dichloromethane is added to the reaction mixture and also a saturated aqueous solution of ammonium chloride. The aqueous phase is extracted with dichloromethane. The organic phases are combined, dried over magnesium sulfate then concentrated using a rotary evaporator under reduced pressure (5 kPa). The crude product obtained (1 g) is purified by flash chromatography over silica (column: 90 g; particle size: 15-40 μm; eluent: 100% dichloromethane to 95% dichloromethane/5% ethyl acetate gradient). After concentrating the fractions under reduced pressure, 0.22 g of 2-benzyl-5-bromo-3,4-dihydroisoquinolin-1(2 H)-one is obtained.

Provenance & Evidence