Polyfluoroheterocyclic compounds. Part VII. Heptafluoro-quinoline and -isoquinoline

Abstract

Heptachloro-quinoline and -isoquinoline have been prepared by initial direct chlorination of quinoline and isoquinoline and subsequent reaction of the products with phosphorus pentachloride at elevated temperatures. Reaction of these perchloro-compounds with potassium fluoride at elevated temperatures gives heptafluoro-quinoline and -isoquinoline in good yields. The perhalogeno-quinolines and -isoquinolines show no basic properties except that they dissolve in concentrated sulphuric acid, and that the solution of heptafluoroquinoline on the slow addition of water or methanol gives the mono-hydroxy or-methoxy-derivatives but on rapid dilution gives heptafluoroquinoline. The mechanism of the reaction is discussed in terms of nucleophilic displacement of fluoride ion from the protonated species.