反应详情

A mixture of 6,7,8-trifluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid ethyl ester (0.3 g), anhydrous potassium carbonate (0.8 g), methyl iodide (1.6 g), and N,N-dimethyl-formamide (DMF) (10 ml) was heated with stirring at 90°-100° C. for 10 hours. The mixture was evaporated to dryness. The residue was treated with water, extracted with dichloromethane. The organic layer was washed with water, dried over anhydrous sodium sulfate, and evaporated. The residue was added to a mixture of 18% hydrochloric acid (5 ml) and ethanol (2.5 ml) and the mixture was refluxed for 2.5 hours. After water (5 ml) and ethanol (5 ml) added and cooled, the resulting precipitate was filtered off and recrystallized from a mixture of DMF and ethanol to give 6,7,8-trifluoro-1,4-dihydro-1-methyl-4-oxoquinoline-3-carboxylic acid (0.22 g), mp 255°-258° C.

1. temperaturewas heated
2. customThe mixture was evaporated to dryness
3. additionThe residue was treated with water
4. extractionextracted with dichloromethane
5. washThe organic layer was washed with water
6. dry with materialdried over anhydrous sodium sulfate
7. customevaporated
8. additionThe residue was added to a mixture of 18% hydrochloric acid (5 ml) and ethanol (2.5 ml)
9. temperaturethe mixture was refluxed for 2.5 hours
10. additionAfter water (5 ml) and ethanol (5 ml) added
11. temperaturecooled
12. filtrationthe resulting precipitate was filtered off
13. customrecrystallized from a mixture of DMF and ethanol