反应详情

温度

130 °C

1-Hydroxypiperazine dihydrochloride (4.64 g), triethylamine (8.9 g) and dimethylsulfoxide (25 ml) are added to 1-cyclopropyl-6,7,8-trifluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (5.0 g), which is prepared according to the procidures described in Japanese Patent First Publication No. 212474/1984, and the mixture is stirred with heating at 130° C. for 45 minutes. After cooling of the mixture to room temperature, the resulting crystals are filtered. To the crystals is added water (20 ml) and the mixture is stirred at 50° C. for 1 hour. The insoluble substance is filtered and recrystallized from a mixture of dimethylformamide and water to afford 1-cyclopropyl-6,8-difluoro-1,4-dihydro-7-(4-hydroxypiperazin-1-yl)-4-oxoquinoline-3-carboxylic acid (4.6 g) as pale yellow prisms, m.p. 223°-227° C. (decomposed with foaming).

1. customis prepared
2. temperatureAfter cooling of the mixture to room temperature
3. filtrationthe resulting crystals are filtered
4. additionTo the crystals is added water (20 ml)
5. stirringthe mixture is stirred at 50° C. for 1 hour
6. filtrationThe insoluble substance is filtered
7. customrecrystallized from a mixture of dimethylformamide and water