Hydrogen Bromide → 8-Ethyl-7-fluoro-1,5-naphthyridin-2(1H)-one

Participants

Reaction Steps

A suspension of 8-ethyl-7-fluoro-2-(methyloxy)-1,5-naphthyridine (1.045 g, 5.07 mmol) in glacial acetic acid (10 ml) at rt under argon, was treated with 33% HBr in acetic acid (10 mL). After stirring at rt for 18 h, the solvents were evaporated under reduced pressure. More glacial acetic acid (10 ml) was added to the reaction mixture and the solvent was removed to give a yellow solid. As this residue was placed in water (ca. 50 ml) a white precipitate came out of solution. The pH was adjusted to pH 6-7 by addition of solid sodium hydrogen carbonate. The mixture was then stirred at rt for 2 h, after which the solid was isolated by filtration with suction to give a white damp solid. This product was dried on the sinter with suction for 2 h then dried in a vacuum oven over 18 h at 40° C. to give the title compound as an white solid (0.81 g, 83%).

Provenance & Evidence