Example 5 Synthesis of 7,8-dihydro-6H-isoquinolin-5-one hydrochloride (8A): 7,8-dihydro-6H-isoquinolin-5-one oxime (50 mmol) was dissolved in acetone (400 mL) and 6N hydrochloric acid (160 mL), and heated to reflux for 15 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was dissolved in ethanol, the solid was collected by filtration and washed sequentially with ethanol and diethyl ether. Drying gave the title compound in 95% yield.ESI (+) MS: m/z 148 (MH+).1H NMR (solvent: DMSO-d6) δ: 2.10 (q, J = 12.53, 6.23 Hz, 1H), 2.70 (d, J = 6.19 Hz, 1H), 2.98 (t, J = 6.10 Hz, 2H), 7.75 (d. J = 5.12 Hz, 1H), 8.65 (d, J = 5.12 Hz, 1H), 8.78 (s, 1H).
