Iodoethane → HCID 13309027, compound

Participants

Reaction Steps

A mixture containing 2.63 g of ethyl 6-fluoro-1,4-dihydro-4-oxo-7-(4-pyridyl)-1,8-naphthyridine-3-carboxylate, 0.42 g of 50% sodium hydride (dispersed in mineral oil) and 30 ml of dimethylformamide was heated at 50°-60° C. for 10 minutes. To the stirred mixture was added 1.31 g of ethyl iodide, and heating was continued for 1.5 hours. The reaction mixture was filtered and the filtrate was concentrated to dryness in vacuo and the residue was taken up in a mixture of chloroform and water. The chloroform layer was separated and the chloroform was evaporated in vacuo to give crystals which were recrystallized from ethyl acetate to yield ethyl 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-pyridyl)-1,8-naphthyridine-3-carboxylate (2.1 g, m.p. 185°-186° C.). This compound was heated at 90°-100° C. with 25 ml of 2N sodium hydroxide for 5 minutes. The reaction mixture was treated with decolorizing charcoal and filtered. The filtrate was adjusted to pH 6-7 with acetic acid and chilled. The resulting solid was collected by filtration and recrystallized from ethanol to give 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-pyridyl)-1,8-naphthyridine-3-carboxylic acid (Compound 1) (1.5 g, m.p. 286°-288° C.).

Provenance & Evidence