Methylamine → 3-Ethoxycarbonyl-7,8,9-trifluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

A solution, at about 5° C., of 10 g of methylamine in 50 cm3 of ethanol is added in the course of 10 minutes, at between 5° and 10° C., to a stirred suspension of 19.3 g of ethyl 2-(2-chloro-6,7,8-trifluoroquinoline-3-carbonyl)-3-dimethylaminoacrylate in 150 cm3 of ethanol kept at a temperature close to 5° C., the mixture is stirred for 1 hour at between 5° and 10° C. and the temperature is allowed to rise to about 20° C. 7.6 g of DBU are added to the solution obtained and the mixture is heated at about 30° C. for 1 hour. After cooling to a temperature close to 20° C., the product is drained and washed with twice 100 cm3 of ethanol and twice 100 cm3 of diisopropyl ether. 13.4 g of 3 -ethoxycarbonyl-7,8,9-trifluoro-1-methyl-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine are obtained in the form of a yellow solid melting at 320° C., which is used for the subsequent steps without further purification.

Provenance & Evidence