Methyl iodide → 7-Methoxy-3,4-dihydroquinolin-2(1H)-one

Participants

Reaction Steps

To a solution of 7-hydroxy-3,4-dihydroquinolin-2(1H)-one (3) (16.317 g, 100 mmol) in anhydrous isopropanol (200 mL) was added potassium carbonate (16.585 g, 120.0 mmol) with stirring under an atmosphere of dry N2. The reaction mixture was stirred at room temperature for 30 minutes, then iodomethane (10.0 mL, 161.3 mmol) was added slowly. The reaction was heated to reflux with stirring for 60 hours, cooled, and the solvent evaporated under reduced pressure. To this residue water (200 mL) was added, and the mixture stirred and sonicated, filtered, and the pale yellow solid was washed with water (1000 mL), and dried under reduced pressure. To the crude dry solid was added 15% ethyl acetate in n-hexane (150 mL), and the mixture sonicated, filtered, washed with n-hexane (50 mL), and dried under reduced pressure, to afford 7-methoxy-3,4-dihydroquinolin-2(1H)-one (15.865 g, 89.5 mmol, 90%), the compound of formula (4). LCMS mz 178.0 (M+H), 200.0 (M+Na), anal HPLC >95% in purity, 1H NMR (400 MHz; dmso-D6) δ 7.09 (d, J=8.2 Hz, 1H); 6.57 (dd, J=8.2 and 2.7 Hz, 1H); 6.48 (d, J=2.7 Hz, 1H); 3.78 (s, 2H); 2.90 (t, J=7.0 Hz, 2H); 2.57 (t, J=7.0 Hz, 2H).

Provenance & Evidence