Triethylamine → Ethyl 6,7-difluoroquinoline-3-carboxylate

Participants

Reaction Steps

A solution of 52.9 g of ethyl 4-chloro-6,7-difluoroquinoline-3-carboxylate in 750 cm3 of ethanol, in the presence of 19.7 g of triethylamine, was hydrogenated at atmospheric pressure, at a temperature in the region of 20° C., for 1 hour in the presence of 3 g of 5% palladium on carbon (type D). After removing the catalyst by filtration at high temperature, being concentrated to dryness under reduced pressure (5.2 kPa) at about 50° C., the residue was taken up, with stirring, in 1.2 liters of water, dewatered, and washed 3 times with 200 cm3 of water. It was dissolved in 1 liter of diethyl ether; the ethereal extracts were washed twice with 100 cm3 of water and were dried over sodium sulphate. After filtration and concentration under reduced pressure (5.2 kPa), the compound obtained was recrystallized from 600 cm3 of diisopropyl ether. 42.8 g of ethyl 6,7-difluoroquinoline-3-carboxylate was obtained in the form of white crystals, which melted at 135° C.

Provenance & Evidence