Methanesulfonic Acid → 6-Fluoro-1,2,3,4-tetrahydroisoquinolin-1-one

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-fluoro-2,3-dihydro-1H-inden-1-one (4.5 g, 29.97 mmol) in dichloromethane (50 ml) was added methanesulfonic acid (40 ml). This was followed by the addition of sodium azide (2.73 g, 42.0 mmol) in several batches with stirring over 2 hours at 0° C. The reaction mixture was then quenched with aqueous sodium hydroxide and extracted with dichloromethane (2×100 ml). The organic layers were combined, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to give a residue, which was purified by silica gel column chromatography using 10%-100% ethyl acetate in petroleum ether to afford 6-fluoro-1,2,3,4-tetrahydroisoquinolin-1-one as a white solid (2.5 g, 51%); (ES, m/z): [M+H]+ 166; 1H NMR (300 MHz, CDCl3): δ 8.11 (dd, J=6.0, 8.7 Hz, 1H), 7.07-7.00 (m, 1H), 6.94 (dd, J=2.4, 8.7 Hz, 1H), 6.57 (br s, 1H), 3.61 (t, J=6.6, 2H), 3.03 (t, J=6.6, 2H).

Provenance & Evidence