N-halogeno-compounds. Part 3. N-Chlorination of some fluorinated aryl- and heteroaryl-amines and anilides

Abstract

t-Butyl hypochlorite has been used to convert 4-aminoheptafluorotoluene, 4-amino-2,3,5,6-tetrafluorobiphenyl, chlorotetrafluoroanilines, 4-amino-3-chlorotrifluoropyridine, and 4-aminotrifluoropyrimidine into the corresponding NN-dichloro-amines; N-methylpentafluoroaniline, tetrafluoro-4-(methylamino)pyridine, 3,5-dichloro-2,6-difluoro-4-(methylamino)pyridine, pentafluoroacetanilide, and pentafluorotrifluoroacetanilide into the corresponding N-monochloro-compounds: and 4,4′-diamino-octafluorobiphenyl into the corresponding bis(dichloroamino)-compound. Treatment of 2,3,4,5-tetrafluoroaniline with t-butyl hypochlorite gave N,4-dichloro-2,3,4,5-tetrafluorocyclohexa-2,5-dienylideneamine and 2H,2′H-octafluoroazobenzene. Perfluoro-(4,4′-dimethylazobenzene) and 2,2′,3,3′,5,5′,6,6′-octafluoro-4,4′-diphenylazobenzene were procured by thermolysis of the appropriate NN-dichloro-amines. Analysis of the ¹⁹F n.m.r. spectra of the dichloro-amines has enabled the electronic effect of the NCl₂ group to be assessed.