反应详情

Employing ethyl 1-ethyl-5-methyl-6,7-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate (0.55 g), conc. hydrochloric acid (1.5 ml) and 90% acetic acid (6 ml), the procedure of Reference Example 10 is repeated to give 1-ethyl-5-methyl-6,7-difluoro-1,4-dihydro-4-oxoquinoline-3- carboxylic acid (0.40 g), as white crystals, m.p. >300° C.