反应详情

2.84 g (0.013 mole) of diethyl ethoxymethylenemalonate were added to 1.74 g (0.011 mole) of 3,4-difluoro-2-methoxyaniline (VIII) (prepared as described in Preparation 13). The mixture was then stirred at 140°-150° C. for 3 hours, after which 20 ml of diphenyl ether were added, and the mixture was stirred at 240°-250° C. for 1 hour. At the end of this time, the mixture was allowed to cool to room temperature, and then hexane was added to precipitate crystals, which were collected by filtration. 1.60 g of ethyl 6,7-difluoro-4-hydroxy-8-methoxyquinoline-3-carboxylate (IX) were obtained as colorless crystals.

1. stirringthe mixture was stirred at 240°-250° C. for 1 hour
2. customto precipitate crystals, which
3. filtrationwere collected by filtration