Water → 5,7-Dichloro-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid

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Reaction Steps

5.2 g of ethyl 5,7-dichloro-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate are heated under reflux in a mixture of 38 ml of acetic acid, 30 ml of water and 4.3 ml of concentrated sulphuric acid for 2.5 hours. After cooling, the mixture is poured into 250 ml of ice-water and the precipitate is filtered off with suction, washed with water and dried. 4.8 g of 5,7-dichloro-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid of melting point 277°-278° C. are obtained.

Provenance & Evidence