Formaldehyde → 1-Cyclopropyl-7-(3,4-dimethyl-1-piperazinyl)-6-fluoro-8-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acid

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Reaction Steps

To 1-cyclopropyl-7-(3-methyl-1-piperazinyl)-6-fluoro-8-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (0.4 g) are added formic acid (3 ml), 37% formalin (3 ml) and sodium formate (0.4 g), and the mixture is refluxed for 5 hours. After cooling, the reaction mixture is poured into ice water and adjusted to below pH 8 with aqueous sodium hydrogen carbonate, and the mixture is extracted with dichloromethane. After removing the solvent by concentration, the resulting residue is recrystallized from ethyl acetate to give 1-cyclopropyl-7-(3,4-dimethyl-1-piperazinyl)-6-fluoro-8-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (0.12 g), as pale yellow powder, m.p. 181°-183° C.

Provenance & Evidence