23308-56-7Relevant articles and documents
The rearrangement of N-triarylmethyl anilines to their p-triarylmethyl derivatives
Siskos, Michael G.,Tzerpos, Nikolaos I.,Zarkadis, Antonios K.
, p. 759 - 768 (2007/10/03)
The N-triarylmethyl anilines Ph3C-NHAr (Ar = Ph, o-Me-C6H4, m-Me-C6H4, p-Me-C6H4, p-O2N-C6H4, p-Ph3C-C6H4) and Ar'3C-NHPh tBu-C6H4)3C> prepared by the reaction of Ph3C-Cl with anilines ArNH2 and of the corresponding chlorides Ar'3C-Cl with aniline (at 50-100 deg C), undergo a Hoffmann-Martius rearrangement to p-triarylmethyl derivatives (i.e., p-Ar'3C-C6H4-NH2 for Ar = Ph) when they are heated (ca. 185 deg C) with equimolar amounts of PhNH3(1+)Cl(1-).The latter catalyses the rearrangement probably through the formation of the instable anilinium salt Ar'3C-NH2Ar(1+)Cl(1-) that serves as a Ar'3C(1+) ion source.Ar'3C(1+) in a second step (electrophilic aromatic substitution) leads with excess of ArNH2 to p-substituted derivatives (e.g. p-Ar'3C-C6H4-NH2).A free radical mechanism, resonable in view of the high temperatures used (ca. 185 deg C), could be excluded; Ar'3C-NHAr undergoes homolysis of the C-N bond to Ar'3C. radicals at temperatures higher than 200 deg C, a fact which was established using ESR spectroscopy and product analysis.
