Hydrochloric Acid → 3-Amino-5-bromo-1-methyl-1,2-dihydropyridin-2-one

Participants

Reaction Conditions

Reaction Steps

A 1-L three-neck round-bottomed flask equipped with a mechanical stirrer and reflux condenser was purged with nitrogen and charged with 41 (21.7 g, 93.3 mmol), ethanol (305 mL), iron powder (−325 mesh, 52.1 g, 933 mmol) and 2N hydrochloric acid (50 mL, 100 mmol), and the mixture was heated for 2 h at 60° C. After this time, the reaction was cooled to room temperature, and potassium carbonate was added to pH 8 as determined by a pH paper. The resulting suspension was filtered and the filter cake washed with ethanol (4×100 mL). The filtrate was concentrated under reduced pressure to yield a brown solid. This solid was purified by column chromatography on silica gel to afford 42 in 77% yield (14.5 g) as an off-white powder: mp 104-105° C.; 1H NMR (500 MHz, DMSO-d6) δ 7.15 (d, 1H, J=2.5 Hz), 6.46 (d, 1H, J=2.5 Hz), 5.45 (bs, 2H), 3.40 (s, 3H); MS (ESI+) m/z 203 (M+H).

Provenance & Evidence