In a 50 mL round-bottomed flask, 1.29 g of isoquinoline, 1.1 g of 35% mass fraction of hydrogen peroxide, 5% mass fraction of perfluorosulfonic acid resin, and 10 mL of water as solvent were sequentially added. The resulting mixture was placed in a 30 W/20 kHz ultrasonic reactor for 15 min. After the reaction was completed, the perfluorosulfonic acid resin catalyst was removed from the system by filtration, the water in the solvent was removed by distillation under reduced pressure, and finally the target product was purified by recrystallization to give 1.39 g of isoquinoline-N-oxide in 96% yield.
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