N-(polyfluoroaryl)-hydroxylamines. Synthesis and properties

Fluorine-containing N-arylhydroxylamines have been obtained by the action of hydroxylamine or its N- and O-derivatives on polyfluorinated benzenes and pentafluoropyridine. The influence of fluorine atoms on the reactivity of hydroxylamino group has been investigated. The reaction of N-polyfluoroarylhydroxylamines with aldehydes has been shown not to occur, whereas their reaction with nitrosobenzenes leads to azoxybenzenes and with Lewis acids leads to corresponding nitrosobenzenes, azoxybenzenes and anilines. The action of acids on 2,3,5,6-tetrafluorophenylhydroxylamine leads to the acid-catalyzed rearrangement of the latter into 4-amino-2,3,5,6-tetrafluorophenol. C,N-Diarylnitrones have been obtained by the oxidation with MnO2 of fluorine-containing arylhydroxylamines possessing the CH-fragment in an α-position.