Methylamine → 3-Ethoxycarbonyl-7,8,9-trifluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

A solution of approximately 5° C. of methylamine (10 g) in ethanol (50 cc) is added in the course of 10 minutes at between 5° and 10° C. to a suspension, maintained at a temperature in the region of 5° C., of ethyl 2-(2-chloro-6,7,8-trifluoro-3-quinolinecarbonyl)-3-(dimethylamino)acrylate (19.3 g) in ethanol (150 cc), the mixture is stirred for 1 hour at between 5° and 10° C. and the temperature is allowed to rise to approximately 20° C. The solution obtained is treated with DBU (7.6 g) and heated to approximately 30° C. for 1 hour. After cooling to a temperature in the region of 20° C., the product is drained and washed with ethanol (2×100 cc) and isopropyl ether (2×100 cc). 3-Ethoxycarbonyl-7,8,9-trifluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine (13.4 g) is obtained in the form of a yellow solid, m.p. 320° C., which is used without further purification for the subsequent steps.

Provenance & Evidence