Hydrochloric Acid → 9-Fluoro-4-methyl-1-oxo-8-pyrrolidinyl-1,4-dihydrobenzo[f][1,7]naphthyridine-2-carboxylic acid

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Reaction Conditions

Reaction Steps

A suspension of 0.8 g of ethyl 9-fluoro-4-methyl-1-oxo-8-pyrrolidinyl-1,4-dihydrobenzo[f][1,7]naphthyridine-2-carboxylate in a mixture of 60 Cm3 of aqueous ethanol at 50% and 2.8 cm3 of a 1 N aqueous potassium hydroxide solution was heated, with stirring, for 2 hours at a temperature of 70° C. After concentration under reduced pressure (5.2 kPa) at 60° C., the residue was dissolved in 100 cm3 of water; the light insoluble material was removed by filtration. The solution obtained was neutralized with 2.8 cm3 of a 1 N aqueous hydrochloric acid solution. The insoluble material formed was dewatered, washed 3 times with 20 cm of water, twice with 15 cm3 of ethanol and dried under vacuum at 100° C. 0.65 g of 9-fluoro-4-methyl-1-oxo-8-pyrrolidinyl-1,4-dihydrobenzo[f][1,7]naphthyridine-2-carboxylic acid was obtained in the form of yellow crystals, which melted at 365° C.

Provenance & Evidence