5-Aryl-2-(3,5-dialkyl-4-hydroxyphenyl)-4,4-dimethyl-4<i>H</i>-imidazole 3-Oxides and Their Redox Species: How Antioxidant Activity of 1-Hydroxy-2,5-dihydro-1<i>H</i>-imidazoles Correlates with the Stability of Hybrid Phenoxyl–Nitroxides
Svetlana A. Amitina,
Elena V. Zaytseva,
Natalya A. Dmitrieva,
Alyona V. Lomanovich,
Natalya V. Kandalintseva,
Yury A. Ten,
Ilya A. Artamonov,
Alexander F. Markov,
Dmitrii G. Mazhukin
Affiliations
Svetlana A. Amitina
Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
Elena V. Zaytseva
Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
Natalya A. Dmitrieva
Department of Chemistry, Institute of Chemistry of Antioxidants, Novosibirsk State Pedagogical University, Vilyuyskaya Str. 28, 6301026 Novosibirsk, Russia
Alyona V. Lomanovich
Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
Natalya V. Kandalintseva
Department of Chemistry, Institute of Chemistry of Antioxidants, Novosibirsk State Pedagogical University, Vilyuyskaya Str. 28, 6301026 Novosibirsk, Russia
Yury A. Ten
Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
Ilya A. Artamonov
Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
Alexander F. Markov
Department of Chemistry, Institute of Chemistry of Antioxidants, Novosibirsk State Pedagogical University, Vilyuyskaya Str. 28, 6301026 Novosibirsk, Russia
Dmitrii G. Mazhukin
Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia
Cyclic nitrones of the imidazole series, containing a sterically hindered phenol group, are promising objects for studying antioxidant activity; on the other hand, they can form persistent hybrid phenoxyl–nitroxyl radicals (HPNs) upon oxidation. Here, a series of 5-aryl-4,4-dimethyl-4H-imidazole 3-oxides was obtained by condensation of aromatic 2-hydroxylaminoketones with 4-formyl-2,6-dialkylphenols followed by oxidation of the initially formed N-hydroxy derivatives. It was shown that the antioxidant activity of both 1-hydroxy-2,5-dihydroimidazoles and 4H-imidazole 3-oxides increases with a decrease in steric volume of the alkyl substituent in the phenol group, while the stability of the corresponding HPNs generated from 4H-imidazole 3-oxides reveals the opposite tendency.
