Hydrochloric Acid → Mefloquine carboxylic acid

Participants

Reaction Steps

A mixture of 100 parts by volume of water, 9.6 parts of sodium hydroxide, 43 parts of 7-trifluoromethylisatin and 26.8 parts of 1,1,1-trifluoroacetone is boiled for 6 hours, under atmospheric pressure, in a reaction vessel equipped with a stirrer, condenser, internal thermometer and feed device. The thin layer chromatogram of a sample taken after this reaction time and worked up with acid no longer shows any 7-trifluoromethyl-isatin. The batch is then allowed to cool, and 2 N hydrochloric acid is added, whilst stirring, until the pH is 2.5. The product which precipitates is washed with water and dried. 57 parts of 2,8-bis-(trifluoromethyl)-quinoline-4-carboxylic acid, ie. 92.2% of theory, are obtained.

Provenance & Evidence