Methanesulfonic Acid → N-benzyl-7-methoxy-1,2-dihydroisoquinolin-4(3H)-one

Participants

Reaction Conditions

Reaction Steps

To a round-bottomed flask containing methanesulfonic acid (75 mL) was added [benzyl-(3-methoxy-benzyl)-amino]-acetic acid (11.0 g, 38.5 mmol) with stirring. The mixture was heated to 100° C. for five hours whereupon LCMS showed completion of the reaction. The mixture was cooled to ambient temperature, water (300 mL) was added and the mixture was cooled in an ice-water bath and adjusted to pH 9 (10N NaOH), keeping the internal temperature below 30° C. The precipitate was collected by vacuum filtration, washed with water to neutrality, and dried to constant weight in vacuo to afford 2-benzyl-7-methoxy-2,3-dihydro-1H-isoquinolin-4-one (7.7 g, 75%) as a tan solid. 1H NMR (400 MHz, DMSO-d6) δ 7.83 (d, J=8 Hz, 1H), 7.34 (m, 5H), 6.95 (d, J=8 Hz, 1H), 6.90 (s, 1H), 3.82 (s, 3H), 3.76 (s, 2H), 3.71 (s, 2H), 3.27 (s, 2H); (m/e) 268 (M+1); mp 135° C. (dec.).

Provenance & Evidence