Hydrochloric Acid → 7-fluoro-1-[(1R,2S)-2-fluorocyclopropyl]-8-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acid

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Reaction Steps

Ethyl 7-fluoro-1-[2-(S)-fluoro-1-(R)-cyclopropyl]-1,4-dihydro-8-methyl-4-oxoquinoline-3-carboxylate (1.40 g, 4.56 mmol) was dissolved in acetic acid (4 ml), and after adding concentrated hydrochloric acid (4 ml) thereto, it was heated under reflux for 3 hours. After cooling, the reaction solution was poured into ice water (50 ml) and the precipitated crystals were filtered out. After washing the filtered-out crystals with an excess amount of water, washing in cold ethanol and washing in diethyl ether were performed in that order, and after drying under a reduced pressure, 1.18 g (93%) of the title compound was obtained in the form of a white powder.

Provenance & Evidence