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

Temperature

60 °C

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).

1. customA 1-L three-neck round-bottomed flask equipped with a mechanical stirrer
2. temperaturereflux condenser
3. customwas purged with nitrogen
4. temperatureAfter this time, the reaction was cooled to room temperature
5. filtrationThe resulting suspension was filtered
6. washthe filter cake washed with ethanol (4×100 mL)
7. concentrationThe filtrate was concentrated under reduced pressure
8. customto yield a brown solid
9. customThis solid was purified by column chromatography on silica gel

ORD record

ord-a5cf592e2d004aaa848de6478e32082a

Source dataset

uspto-grants-2011_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07884108B2