Ethanol → 6,8-Difluoro-1-(2-fluoroethyl)-1,4-dihydro-7-(4-methyl-1-piperazinyl)-3-quinolinecarboxylic acid ethyl ester

関与物質

反応手順

To a stirred suspension of 6,8-difluoro-1-(2-fluoroethyl)-1,4-dihydro-7-(4-methyl-1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid (Fleroxacin; Belgian Patent No. 887,574) (35 g, 0.095 mol) in anhydrous ethanol (2.0 L) was added dropwise thionyl chloride (184 mL, 2.52 mol) over a 2-hour period. The solution was then heated at reflux and monitored by thin layer chromatography, until all starting material had been consumed (at this point a clear solution was obtained). The mixture was evaporated to dryness (36.3 g) and recrystallized from ethanol to give a white crystalline solid (30.4 g, 81% yield).

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