反应详情

Concd. sulfuric acid (300 ml) was added to ethyl 2-(3-acetoxy-2-oxopropylthio)-6,7,8-trifluoro-4-hydroxyquinoline-3-carboxylate (36.0 g) and the mixture was stirred at room temperature for 45 minutes and then at 85° C. for 19 hours. After adding ice-water (250 g) with cooling, the mixture was stirred at room temperature for 3 hours and the reaction mixture was then poured into ice-water. After precipitated crystal was filtered and washed with water, the resultant was recrystallized from a mixed solvent of chloroform - methanol to give the title compound (14.2 g) as light brown crystals, m.p. 220° C. (dec.).

1. waitat 85° C. for 19 hours
2. temperaturewith cooling
3. stirringthe mixture was stirred at room temperature for 3 hours
4. customAfter precipitated crystal
5. filtrationwas filtered
6. washwashed with water
7. customthe resultant was recrystallized from a mixed solvent of chloroform - methanol