Hydrogen Bromide → HCID 13044296, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 7 g of 9-fluoro-8-bromo-5-methyl-6,7-dihydro-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid, 12 g of 4-dimethylaminopiperidine and 50 ml of hexamethylphosphoric triamide was heated at 150° C. on an oil bath for 5 hours. After completion of reaction, hexamethylphosphoric triamide was distilled off under reduced pressure and to the residue was added ethyl acetate to form crystals. The crystals were suspended in 500 ml of water and a 47% aqueous hydrobromic acid was added thereto to adjust pH to 3 followed by heating. Then, insoluble substances were removed by filtration. The filtrate was concentrated and the residue was recrystallized from ethanol-water. Crystals which formed were dissolved in a 10% aqueous sodium hydroxide solution and the resulting solution was adjusted to pH 8 with dilute hydrochloric acid to precipitate white crystals, which then were dried to give 2.4 g of 9-fluoro-8-(4-dimethylamino-1-piperidyl)-5-methyl-6,7-dihydro-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid. m.p. 259°-261° C., white rhombic crystals.

Provenance & Evidence