Ethylamine → 8-Chloro-3-ethoxycarbonyl-1-ethyl-7-fluoro-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

Ethylamine (16 g) is added in the course of 5 minutes at between 10° and 15° C. to a stirred suspension of ethyl 2-(2,7-dichloro-6-fluoro-3-quinolinecarbonyl)-3-(dimethylamino)acrylate (13.5 g) in ethanol (135 cc), the temperature is allowed to rise to approximately 20° C., DBU (0.5 g) is added and the mixture is heated with stirring for 2 hours to a temperature in the region of 75° C. After cooling to a temperature in the region of 20° C., the precipitate is drained and washed with ethanol (2×100 cc) and ethyl ether (2×100 cc). 8-Chloro-3-ethoxycarbonyl-1-ethyl-7-fluoro-4-oxo-1,4-dihydrobenzo[b][1, 8]naphthyridine (10.4 g) is obtained in the form of a yellow solid, m.p. 300°-301° C., which is used without further purification for the subsequent steps.

Provenance & Evidence