Diethyl (ethoxymethylene)malonate → Ethyl 7-chloro-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate

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Reaction Steps

A mixture of 3-chloro-4-fluoroaniline (1.46 g) and diethyl ethoxymethylene malonate (2.16 g) was heated at 120°-130° C. After 2 hours, the resulting ethanol was evaporated off. The residue was added to diphenyl ether (50 ml) and refluxed for 1 hour. After the solution cooled, the resulting precipitate was filtered, washed with benzene, and dried. The solid was recrystallized from N,N-dimethylformamide (DMF) to give 7-chloro-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid ethyl ester (3.2 g).

Provenance & Evidence