General procedure for the synthesis of 6-aminoisoquinoline from 6-bromoisoquinoline: 17.2 g of 6-bromoisoquinoline (see WO 2008/077553), 200 mL of 28% ammonia solution and 10.8 g of copper (II) sulfate pentahydrate were placed in an autoclave and sealed. The mixture was stirred and reacted at 190 °C for 6 hours. After completion of the reaction, it was cooled to room temperature and the reaction solution was poured into 250 mL of 10% aqueous sodium hydroxide solution and extracted with ethyl acetate (100 mL each time, 5 times). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and concentrated. The resulting crude product was suspended with dichloromethane and filtered to give 10.2 g of light brown crystalline 6-aminoisoquinoline in 85% yield.1H-NMR spectrum (CDCl3, δ ppm): 5.54 (broad single peak, 2H), 6.58 (single peak, 1H), 7.00 (double peak, J = 9.0 Hz, 1H), 7.35 (double peak, J = 5.5 Hz, 1H), 7.75 (double peak, J = 5.5 Hz, 1H). 7.75 (double peak, J = 9.0 Hz, 1H), 8.32 (double peak, J = 5.5 Hz, 1H), 8.98 (single peak, 1H).
