Formic Acid → Ethyl 6,7-difluoro-1-(formylamino)-8-methoxy-1,4-dihydro-4-oxoquinoline-3-carboxylate

Participants

Reaction Steps

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.

Provenance & Evidence