Water → Ethyl 7-fluoro-1-[2-(S)-fluoro-1-(R)-cyclopropyl]-1,4-dihydro-8-methyl-5-nitro-4-oxoquinoline-3-carboxylate

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Reaction Conditions

Reaction Steps

Isoamyl nitrite (2.56 ml, 19.1 mmol) was added to dimethylformamide (40 ml), and while stirring at 65° C., a solution, wherein ethyl 6-amino-7-fluoro-1-[2-(S)-fluoro-1-(R)-cyclopropyl]-1,4-dihydro-8-methyl-5-nitro-4-oxoquinoline-3-carboxylate (5.00 g, 13.6 mmol) was dissolved in dimethylformamide (60 ml), was added dropwise over a period of 3 hours. After completion of dripping, the reaction solution was stirred at 65° C. for 4 hours, allowed to cool, and then poured into water (500 ml). After extraction with chloroform (200 ml×3), the organic layers combined were washed with 1 mol/l hydrochloric acid (200 ml) and saturated saline solution (100 ml×2) in that order, and then dried over anhydrous sodium sulfate. After filtering, the filtrate was concentrated under a reduced pressure, and the residue obtained was applied to a silica gel chromatography to obtain 2.91 g (61%) of the title compound in the form of a white powder from a chloroform:methanol=30:1 eluate.

Provenance & Evidence