Triethylamine → 3-Ethoxycarbonyl-7,8-difluoro-1-methoxy-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

A suspension of methoxylamine hydrochloride (1.7 g) in trichloromethane (40 cc) is treated with triethylamine (2.13 g). After 15 minutes' stirring at a temperature in the region of 20° C., the solution obtained is treated with ethyl 2-(2-chloro-6,7-difluoro-3-quinolinecarbonyl)-3-(dimethylamino)acrylate (3.69 g) and stirred for 4 hours and a half at approximately 20° C. The reaction mixture is concentrated to dryness under reduced pressure (20 kPa) at a temperature in the region of 50° C. The residue is taken up with ethanol (70 cc) and triethylamine (3.6 g) and heated for 30 minutes to a temperature in the region of 75° C. After cooling to approximately 20° C., the precipitate obtained is drained and washed with ethanol (3×30 cc). 3-Ethoxycarbonyl-7,8-difluoro-1-methoxy-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine (2.67 g) is obtained in the form of a pale yellow solid, m.p. 266°-268° C.).

Provenance & Evidence