Nucleophilic aromatic substitution of hydrogen in the reaction of tert-alkylamines with nitrosobenzenes - Synthesis and NMR study of N-(tert-alkyl)-ortho-nitrosoanilines

The reaction of primary amines bearing tertiary alkyl groups (e.g. R-NH2; R = tBu, 1-adamantyl) with nitrosobenzenes has been found to proceed by oxid ative nucleophilic aromatic substitution of hydrogen, thereby affording N-( tert-alkyl)-ortho- and -para-nitrosoanilines. The replacement of hydrogen p roceeds more rapidly than the replacement of ortho- or para-nitro or -bromo substituents. With p-nitronitrosobenzene, both ortho-hydrogen atoms are su bstituted to afford N,N'-di(tert-alkyl)-4-nitro-2-nitroso-1, phenylenediami nes 8a,b. The addition of oxidizing agents (e.g. MnO2) increases the yield of products. H-1-, C-13-, N-14- and N-15-NMR studies have confirmed the str uctures oi the compounds under investigation. In ortho-nitrosoanilines, the rotamer with the nitroso group syn to the amino group is favored.