Cyclopropylamine → 1-Cyclopropyl-3-ethoxycarbonyl-7,8,9-trifluoro-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

4.12 g of cyclopropylamine are added in the course of 5 minutes to a solution of 7 g of ethyl 2-(2-chloro-6,7,8-trifluoroquinoline-3-carb onyl)-3-dimethylamino-acrylate in 100 cm3 of trichloromethane kept at a temperature close to 20° C. and the mixture is stirred for a further 4 hours at this temperature. The reaction mixture is concentrated under reduced pressure (20 kPa) at about 50° C. The oily residue obtained is taken up in 100 cm3 of ethanol and 3 g of DBU. The mixture is heated to 80° C. and kept at this temperature, with stirring, for 1 hour and a half. After cooling to about 20° C., the insoluble matter is drained and washed with twice 30 cm3 of ethanol and twice 30 cm3 of diisopropyl ether. 4.5 g of 1-cyclopropyl-3-ethoxycarbonyl-7,8,9-trifluoro-4-oxo-1,4-dihydro-benzo[b][1,8]naphthridine are obtained in the form of a colourless solid melting at 260° C.

Provenance & Evidence