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Small amounts of Fe(II) salt initiate redox chains with hydroxyamino-O-sulfonic acid (HSA) and aromatic compounds leading to the amination of the aromatic ring. The positional and substrate selectivity with a variety of substituted benzenes show the important role of the electrophilic character of the radical -+NH3. Hammett relationships with and + are roughly observed. The lower sensitivity to polar effects of the radical •+ 3 compared with (CH3)2+NH• is explained by the different reaction enthalpies. The different positional selectivity obtained with anisóle and the redox system +NH3OH/Ti(III) is discussed.The amination of aromatic compounds by AVV-dialkyl, R2+ÑH, and jV-monqalkyl, R+ÑH2, amino radical cations from iV-alkylchloramines in acidic medium is particularly interesting for the synthetic and theoretical involvements.1 The exceptional positional and substrate selectivity, observed with many aromatic substrates has been ascribed to the polar effects connected with the strong electrophilic character of the alkylamino radical cations and with a charge-transfer character of the transition state1 (eq 1).The behavior of the simple amino radical cation, •+ 3, for which a similar trend would be expected, has been less investigated. Unfortunately the use of the iV-chloramine, NH2C1, in acidic medium in order to have a homogeneous comparison proved to be unsuitable.Years ago two different radical sources were investigated for the aromatic amination by •+ 3, the redox couples +NH3OH/Ti(III)2 (eq 2) and +NH30S037Fe(II)3 (eq 3).

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