反应详情

A solution was prepared by dropping 1.5 ml (0.04 mole) of formic acid onto 3.8 ml (0.04 mole) of acetic anhydride, whilst ice-cooling, and then stirring the mixture at the same temperature for 15 minutes and then at 50° C. for 15 minutes. This solution was added dropwise to a solution of 0.6 g (0.002 mole) of ethyl 1-amino-6,7-difluoro-8-methoxy-1,4-dihydro-4-oxoquinoline-3-carboxylate (XV) [prepared as described in Step (D1) above] dissolved in 4.2 ml (0.11 mole) of formic acid, whilst ice-cooling. The mixture was stirred at room temperature for 9 hours. At the end of this time, the solvent was distilled off under reduced pressure from the mixture. The residue was washed, in turn, with water and diethyl ether, to give 0.6 g of ethyl 6,7-difluoro-1-(formylamino)-8-methoxy-1,4-dihydro-4-oxoquinoline-3-carboxylate (XVI) as a pale yellow powder.

1. customA solution was prepared
2. temperaturewhilst ice-cooling
3. waitat 50° C. for 15 minutes
4. temperaturecooling
5. stirringThe mixture was stirred at room temperature for 9 hours
6. distillationAt the end of this time, the solvent was distilled off under reduced pressure from the mixture
7. washThe residue was washed, in turn, with water and diethyl ether