General procedure for the synthesis of 4-bromo-1(2H)-isoquinolinone from 1-hydroxyisoquinoline: N-bromosuccinimide (NBS, 142 mg, 0.796 mmol) was added to a solution of DMF (2 mL) containing isoquinolin-1(2H)-one (105 mg, 0.723 mmol). The reaction mixture was stirred at room temperature for 2 hours. After completion of the reaction, the mixture was concentrated to remove the solvent. The crude product was purified by preparative high performance liquid chromatography (HPLC) to afford the intermediate 6 4-bromoisoquinolin-1(2H)-one (110 mg, 68% yield). [C] MS (ESI) m/z: 223.9 (M + H)+. 1H NMR (500 MHz, DMSO-d6) δ 11.57 (br.s, 1H), 8.24 (dd, J = 8.0, 0.8 Hz, 1H), 7.88-7.83 (m, 1H), 7.79-7.75 (m, 1H), 7.61 (ddd, J = 8.0, 7.1, 1.1 Hz, 1H), 7.55 (s, 1H).
