反应详情

To ethyl 1-cyclopropyl-6,7,8-trifluoro-5-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylate (4.10 g) are added 90% acetic acid--conc. hydrochloric acid (4:1, 81.25 ml) and the mixture is refluxed for 2 hours. After cooling, the precipitated crystals are isolated, washed with water, ethanol, and diethyl ether in this order to give 1-cyclopropyl-6,7,8-trifluoro-5-methyl-1,4,-dihydro-4-oxoquinoline-3-carboxylic acid (3.47 g), as white needles, m.p. 218°-220° C.

1. temperatureAfter cooling
2. customthe precipitated crystals are isolated
3. washwashed with water, ethanol, and diethyl ether in this order