Reactions of the N-carbazolyl radical

Abstract

An attempt has been made to prepare and study the N-carbazolyl free radical. It can be obtained by thermolysis or photolysis of NN′-azocarbazole and is evidently a transient intermediate in the oxidation of carbazole with potassium permanganate or silver oxide. In inert solvents these reactions yield NN′-dicarbazolyl, 3,9′-dicarbazolyl, carbazole, and telomers in which carbazolyl radicals are linked together through either the 3-(=C) or the 9-(=N) positions. Thus N-carbazolyl radicals can attack the 3-positions of other carbazolyl radicals or of NN′-dicarbazolyl. They can also abstract hydrogen from the α-positions of toluene, cumene, and p-xylene; from reaction in the last solvent both bi-p-xylyl (4,4′-dimethylbibenzyl) and N-xylylcarbazole have been isolated. Products were identified by a combination of spectrographic techniques, and a number of new N-arylcarbazoles have been prepared.