108275-03-2Relevant articles and documents
Radical Reactions of N-Heterocyclic Compounds. IV. ESR Investigation of H-Transfer between Aminic Antioxydants and Peroxy Radicals
Tkac, A.,Omelka, L.,Schulz, M.,Moegel, L.
, p. 71 - 80 (2007/10/02)
The N-radicals of pyrazole-, imidazole- and indole-derivatives were prepared in comparatively high concentrations at room temperature in benzene or toluene and their e.s.r. signals were interpreted.In H-abstraction by free or to Co(III)-coordinated tert-butylperoxy radicals from bifunctional heterocyclic substituted amines 2-9, 11 the following efficiency was ascertained: unhindered - OH - > aniline-NH > heterocyclic-NH-, hindered OH-groups.No radical attack on the exocyclic NH2-group took place.The splitting constant concerning the heterocyclic nitrogen of nitroxyl radicals 5a, 10a was in the range aNendo = 0.7 to 0.85 mT in contrast to exocyclic nitroxyls 6a,8a,9a,11a possessing aNexo = 1.0 to 1.1 mT.The interruption of the ?-conjugation betweeen the heterocyclic and the aniline groups by insertion of a CH2-group led to the decrease of the stability of the generated N-radicals.In the case of anilinebenzimidazole 9 the Co(III)-complexed endocyclic aminyl radical 9b was observed simultaneously with the exocyclic nitroxyl radical 9a.
