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

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Reaction Steps

A solution at approximately 2° C. of ethylamine (14.6 g) in ethanol (200 cc) is added in the course of 10 minutes at between 2° and 5° C. and with stirring to a suspension of ethyl 2-(2-chloro-6,7-difluoro-3-quinolinecarbonyl)-3-(dimethylamino)acrylate (20 g) in ethanol (200 cc) at approximately 2° C., the mixture is stirred for a further 40 minutes at between 2° and 5° C. and the temperature is then allowed to rise to approximately 20° C. in the course of 2 hours. After 24 hours at approximately 20° C., the insoluble matter is drained and washed with ethanol (2×30 cc) and isopropyl ether (2×50 cc). 3-Ethoxycarbonyl-1-ethyl-7,8-difluoro-4-oxo-1,4-dihydrobenzo [b][1,8]naphthyridine (16.35 g) is obtained in the form of a beige solid, m.p. 290° C.

Provenance & Evidence