Triethylamine → 5-Amino-7-(3-methylaminopiperidin-1-yl)-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylic acid

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Reaction Steps

A suspension of 5-amino-1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylic acid (1.039 g), 3-methylaminopiperidine hydrochloride (1.5 g) and triethylamine (2.5 g) in acetonitrile (30 ml) and N,N-dimethylformamide (10 ml) was refluxed overnight. Concentration of thereaction mixture followed by purification by silica gel column chromatography (chloroform:methanol:ammonium hydroxide=15:5:1) gave a yellow crystalline substance [MS m/e: 404 (M+)]. The crystalline substance thus obtained was recrystallized from ethanol to afford 5-amino-7-(3-methylaminopiperidin-1-yl)-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-4-oxoquinoline-3-carboxylic acid (400 mg) as yellow needles. m.p. 265°-275° C. (decomposition).

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