Mechanism of the chlorination of anilines and related aromatic amines. Involvement of nitrenium ions

Aryl Nitrenium Ions in Aqueous Solution

“…[57][58][59] In an attempt to detect nitrenium ions directly in superacid media, Olah instead generated the dicationic species 13 characterized by 13 Gassman and coworkers examined the solvolysis of N-tert-butyl-N-chloroanilines 14 (Scheme 4.5) in methanol and ethanol starting in 1968. [60][61][62][63][64] In buffered ethanol the solvolysis rate constants for 14a-f correlate with s þ with r þ of À6.4. 62,64 The major products are 15 and the anilines 16.…”

“…[60][61][62][63][64] In buffered ethanol the solvolysis rate constants for 14a-f correlate with s þ with r þ of À6.4. 62,64 The major products are 15 and the anilines 16. Unsubstituted 14c also yields 16d (11% compared to 48% of 15c).…”

“…Often concerted reactions could not be ruled out because kinetics experiments had not been performed. Reduction products had been attributed to triplet ions, [60][61][62][63][64]72 but calculations suggested that triplet ions are not accessible in thermal processes. 101 Singlet ions can also be reduced under certain conditions.…”

A non-target approach to identify disinfection byproducts of structurally similar sulfonamide antibiotics

“…There are two additional lines of evidence that support the proposed N-chlorinated structure. First, studies on halogenation patterns of para-substituted anilines predict N-chlorination (Gassman and Campbell, 1971). Second, the confirmed formation of SMX142, an N-chlorinated product, provides structural evidence of N-chlorination on a downstream transformation product.…”

Anilines as Nucleophiles

“…N-Chloroanilines undergo acid-catalyzed rearrangement in nonpolar solvents to yield a mixture of 2-Cl, 4-Cl and 2,4-Cl 2 anilines. Based on the high ortho-para ratio, an intramolecular rearrangement of N-chloroanilines was proposed 146 . However, Paul and Haberfield 147 were unable to find conclusive evidence for an intramolecular mechanism for the acid-catalyzed rearrangement of N-chloroanilines, and the results can be equally interpreted to support an intermolecular transfer of chlorine to the ortho and para ring positions of anilines.…”