Hydrochloric Acid → Methyl 6,7,8-trifluoro-1-methylamino-1,4-dihydro-4-oxoquinoline-3-carboxylate

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Reaction Steps

To ethyl acetate solution (55 ml) of 4N hydrochloric acid, was added methyl 1-(N-tert-butoxycarbonyl-N-methylamino)-6,7,8-trifluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate (10.85 g) with ice-cooling, and the mixture was stirred for one hour at the same temperature and then for 14 hours at room temperature. The mixture was concentrated under reduced pressure to obtain a solid. The solid was poured into a mixture comprising methylene chloride (150 ml) and water (150 ml). The suspension was neutralized with sodium hydrogencarbonate. The precipitates were taken out by filtration, washed with water and dried with phosphorus pentaoxide to obtain a solid. The solid was recrystallized from a liquid mixture of methylene chloride and diisopropyl ether to obtain methyl 6,7,8-trifluoro-1-methylamino-1,4-dihydro-4-oxoquinoline-3-carboxylate (4.05 g).

Provenance & Evidence