Piperidine → HCID 13044288, compound

Participants

Reaction Conditions

Reaction Steps

In a 200 ml autoclave were placed 5 g of 9-fluoro-8-bromo-5-methyl-6,7-dihydro-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid, 5 g of piperidine and 45 ml of hexamethylphosphoric triamide and the mixture was stirred at 160° C. After 5.5 hours, the temperature was lowered to room temperature and disappearance of the starting materials was confirmed by thin layer chromatography followed by removing hexamethylphosphoric triamide using a vacuum pump (120° C./2 mm Hg). To the residue was added several drops of concentrated hydrochloric acid and then ethyl acetate. Crystals which formed were collected by filtration and washed with ethyl acetate. The crystals thus obtained were recrystallized from dimethylformamide-water and the resulting crystals were added sodium hydroxide and water so as to obtain an aqueous solution of pH 13 which then was treated with activated carbon and filtered. The filtrate was adjusted to pH 7 with acetic acid to precipitate crystals which then were collected by filtration and recrystallized from dimethylformamide-water to give 570 mg of 9-fluoro-8-(1-piperidyl)-5-methyl-6,7-dihydro-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid. m.p. 258°-261° C., white rhombic crystals.

Provenance & Evidence