Hydrochloric Acid → 1-Cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-{4-[(3-methoxycarbonylpropyl)-carbamoyl]-piperazin-1-yl}-quinoline-3-carboxylic acid

Participants

Reaction Steps

6.6 g (0.02 mol) of 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(piperazin-1-yl)-quinoline-3-carboxylic acid are dissolved in a solution of 0.4 g of sodium hydroxide in 40 ml of water, and a solution of 3.2 g (0.022 mol) of methyl 4-isocyanato-butyrate in 12 ml of dioxane is added, while cooling with ice. Thereafter, stirring is continued for 2 hours at room temperature, the pH is adjusted to 5 with 2N hydrochloric acid and the precipitate is filtered off under suction and recrystallised from methanol. 6 g (63% of theory) of 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-{4-[(3-methoxycarbonylpropyl)-carbamoyl]-piperazin-1-yl}-quinoline-3-carboxylic acid of melting point 198°-200° C. are obtained.

Provenance & Evidence