Polyfluoroarenes. Part XX. Some homolytic arylations with pentafluorophenylhydrazine
Abstract
Oxidation of pentafluorophenylhydrazine in benzene by aqueous reagents (CuSO4, NaOCl, H2O2, and H2O2–FeSO4) gives 2,3,4,5,6-pentafluorobiphenyl. Use of solid potassium permanganate in pyridine or silver oxide in a solution of naphthalene in carbon tetrachloride gives low yields of the corresponding pentafluorophenylarenes, but a 57% yield of 2,3,4,5,6-pentafluoro(phenoxy)biphenyls is obtained from the hydrazine and silver oxide in molten diphenyl ether. The isomer ratio for the last reaction has been determined. Unambiguous syntheses of the two pentafluorophenylnaphthalenes and the three 2,3,4,5,6-pentafluoro(phenoxy)biphenyls are described.