反应详情

1-((S)-1-tert-butyldimethylsilyloxymethyl-2-methylpropyl)-6-(3-chloro-2-fluorobenzyl)-7-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid ethyl ester (19 g, 33 mmol) obtained in Example 1, Step 5 was dissolved in isopropanol (100 ml), 1N aqueous sodium hydroxide solution (200 ml, 200 mmol) was added, and the mixture was heated under reflux for 2.5 hr. The reaction mixture was allowed to cool to room temperature, and the mixture was filtered through Celite. The filtrate was acidified by adding concentrated hydrochloric acid, and stirred at room temperature for 2 hr. The precipitated solid was collected by filtration and vacuum dried to give 6-(3-chloro-2-fluorobenzyl)-7-fluoro-1-((S)-1-hydroxymethyl-2-methylpropyl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (12 g, yield 82%) as a pale-yellow solid.

1. temperaturethe mixture was heated
2. temperatureunder reflux for 2.5 hr
3. filtrationthe mixture was filtered through Celite
4. additionby adding concentrated hydrochloric acid
5. filtrationThe precipitated solid was collected by filtration and vacuum
6. customdried