Polyfluoroheterocyclic compounds. Part XIV. Some reactions of tetrafluoroisonicotinic acid and pentafluorobenzoic acid

Abstract

The anhydride and acid chloride of tetrafluoroisonicotinic acid have been made and used to prepare substituted amides and hydrazines. NN′-Di(tetrafluoroisonicotinoyl)hydrazine undergoes cyclodehydration when treated with phosphoryl chloride or phosphorus pentasulphide, to give 2,5-di(tetrafluoro-4-pyridyl)-1,3,4-oxadiazole and -thiadiazole respectively. Tetrafluoroisonicotinoyl fluoride reacts with the heptafluoroisopropyl anion, prepared from hexafluoropropene and fluoride ion, to give perfluoro(isopropyl 4-pyridyl ketone). Some of these reactions have been duplicated with pentafluorobenzoyl chloride and pentafluorobenzoyl fluoride. In addition to forming a ketone with the heptafluoroisopropyl anion, the latter also undergoes nycleophilic substitution in the ring to give perfluoro(isopropyl 4-isopropylphenyl ketone).