Triethylamine → 3-Ethoxycarbonyl-7,8-difluoro-1-methoxy-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

2.13 g of triethylamine are added to a suspension of 1.7 g of methoxylamine hydrochloride in 40 cm3 of trichloromethane. After stirring for 15 minutes at a temperature close to 20° C., 3.69 g of ethyl 2-(2-chloro-6,7-difluoroquinoline-3-carbonyl)-3dimethylaminoacrylate are added to the solution obtained and the mixture is stirred for 4 hours and a half at about 20° C. The reaction mixture is concentrated to dryness under reduced pressure (20 kPa) at a temperature close to 50° C. The residue is taken up in 70 cm3 of ethanol and 3.6 g of triethylamine and the mixture is heated for 30 minutes at a temperature close to 75° C. After cooling to about 20° C., the precipitate obtained is drained and washed with 3 times 30 cm3 of ethanol. 2.67 g of 3-ethoxycarbonyl-7,8-difluoro-1-methoxy-4-oxo-1,4-dihydro-benzo[b] [1,8]naphthyridine are obtained in the form of a pale yellow solid melting at 266°-268° C.

Provenance & Evidence