Diethyl (ethoxymethylene)malonate → Diethyl 2-((4-fluoro-3-nitroanilino)methylene)malonate

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Reaction Steps

50 g of 4-fluoro-3-nitroaniline and 69 g of ethoxymethylene malonic acid-diethyl ester were heated for 3 hours to 120° C. The mixture was added to n-hexane, stirred for 2 hours, and the crystalline material was suctioned off and dried in a vacuum at room temperature. 93 g of N-(4-fluoro-3-nitrophenyl)-aminomethylene malonic acid diethyl ester is obtained. The latter is added in 3 portions of 31 g to respectively 150 ml of a mixture that consists of 26.5% diphenyl and 73.5% diphenyl ether (DOWTHERM A⊕) that is preheated to 260° C., and it is stirred for 30 minutes at this temperature. After cooling, it is diluted with 500 ml of n-hexane, and the precipitate is suctioned off. A total of 64 g of a mixture of 1,4-dihydro-6-fluoro-5-nitro-4-oxo-quinoline-3-carboxylic acid ethyl ester and 1,4-dihydro-6-fluoro-7-nitro-4-oxo-quinoline-3-carboxylic acid-ethyl ester is obtained.

Provenance & Evidence