6-Methyl-3,4-dihydroisoquinolin-1(2H)-one

147497-32-3

13061-96-6

1082041-78-8

To a mixture of 6-bromo-3,4-dihydro-2H-isoquinolin-1-one (19.0 g, 82.4 mmol), methylboronic acid (20.8 g, 329 mmol), and sodium carbonate (18.4 g, 165 mmol) was added 1,4-dioxane (200 mL) and water (10.0 mL) under nitrogen protection, followed by the addition of [1,1'-bis ( diphenylphosphino)ferrocene]palladium(II) dichloride (2.46 g, 3.29 mmol). The reaction mixture was stirred at 105 °C under nitrogen atmosphere for 16 hours. After completion of the reaction, the suspension was filtered through a diatomaceous earth pad and the filter cake was washed with dichloromethane (3 x 250 mL). The combined filtrates were washed sequentially with water (100 mL) and brine (80 mL), dried with anhydrous sodium sulfate, and concentrated under reduced pressure to remove the solvent. The crude product was purified by rapid chromatography on silica gel, using a gradient elution from petroleum ether to 50% ethyl acetate, to afford 6-methyl-3,4-dihydroisoquinolin-1(2H)-one (13.0 g, 95.2% yield) as a yellow solid.ESI-MS (m/z): 162.0 ([M+H]+).1H NMR (400 MHz, CDCl3) δ: 7.94 (d, J = 8.0 Hz, 1H), 7.15 (d, J = 7.8 Hz, 1H), 7.02 (s, 1H), 6.89 (br s, 1H), 3.55 (dt, J = 2.9, 6.6 Hz, 2H), 2.94 (t, J = 6.5 Hz, 2H), 2.37 (s, 3H).