5-Amino-1-cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid → 7-(4-Acetyl-3-methyl-1-piperazinyl)-5-amino-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid

Participants

Reaction Steps

A mixture of 5-amino-1-cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid, 1-acetyl-2-methylpiperazine and pyridine was heated under reflux for 5 hours. The reaction mixture was concentrated under reduced pressure, and the residue was dissolved in aqueous ammonia. The solution was neutralized with an aqueous solution of acetic acid and cooled with ice. The crystals were collected by filtration to give 7-(4-acetyl-3-methyl-1-piperazinyl)-5-amino-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid. It was recrystallized from ethanol/chloroform. m.p. 269°-271° C.

Provenance & Evidence