Hydrochloric Acid → 5-Amino-7-(3-aminopiperidin-1-yl)-1-cyclopropyl-6,8-difluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid

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Reaction Steps

A suspension of 5-amino-1-cyclopropyl-6,7,8-trifluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (1.3 g), 3-aminopiperidine hydrochloride (0.905 g), triethylamine (3.0 g) in acetonitrile (40 ml) was refluxed for 5 hours and the reaction mixture was then cooled to room temperature. Removal of the solvent followed by purification by silica gel column chromatography (chloroform:methanol:ammonium hydroxide=15:5:1) gave a yellow crystalline substance [MS m/e: 378 (M+)]. The crystalline substance thus obtainedwas suspended in isopropanol and the suspension was adjusted to pH about 1-2 with 10% aqueous hydrochloric acid. Filtration of the precipitated crystals followed by recrystallization from ethanol afforded hydro-chloride of 5-amino-7-(3-aminopiperidin-1-yl)-1-cyclopropyl-6,8-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (0.6 g). m.p. 265° C. (decomposition).

Provenance & Evidence