Alkyl Nitrite-Metal Halide Deamination Reactions. 7. Synthetic Coupling of Electrophilic Bromination with Substitutive Deamination for Selective Synthesis of Multiply Brominated Aromatic Compounds from Arylamines

Article abstract of DOI:10.1021/jo01301a004

Aromatic amines undergo substitution with copper(II)bromide that is in competition with substitutive deamination when these reactions are performed with tert-butyl nitrite.Except for the exceptionally reactive 4-substituted 1-aminonaphthalenes,which undergo selective bromine substitution at the 1- and 2-positions in relatively high isolated yields,rates for oxidative bromination and substitutive deamination are not sufficiently different that selective multiple bromination can be achieved.Oxidative bromination of N,N-dimethylaniline by copper(II)bromide occurs with partial dealkylation,and nitration products are observed from reactions performed with copper(II)bromide and tert-butyl nitrite.Implications of these results for the successful utilization of copper(II)bromide/tert-butyl nitrite combinations in substitutive deamination reactions of aromatic amines are discussed.Multiply brominated aromatic compounds are produced from aromatic amines in high yield through treatment of the aromatic amine with the combination of molecular bromine and catalytic quantities of copper(II)bromide and,following a normally brief time delay,with tert-butyl nitrite.All unsubstituted aromatic ring positions ortho and para to the amino group,as well as the position of the amino group,are substituted by bromine.The only observed byproducts from use of this procedure (usually <2percent yield) are the partially brominated benzene derivatives.