N 52 New approach to synthesis of nitronyl and imino nitroxides based on S(N)(H) methodology [Text] / E. V. Tretyakov, I. A. Utepova, M. V. Varaksin, S. E. Tolstikov, G. V. Romanenko, A. S. Bogomyakov, D. V. Stass, V. Ovcharenko, O. N. Chupakhin // ARKIVOC. - 2011. - Part 8. - P76-98 : ил. - Bibliogr. : p. 98 (36 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: It is shown that S(N)(H) approach opens new possibilities in the synthesis of polyfunctional nitronyl and imino nitroxides. It is found that the interaction of 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl lithium salt Li1 with 3,6-diaryl-1,2,4-triazines leads to formation of the corresponding triazines bearing nitronyl nitroxide or imino nitroxide substituent at position 5 of the heterocycle. The reaction of Li1 with pyridazine-N-oxide gives rise to nitroxide with buten-3-ynyl substituent 5. Spin-labeled 5 could be readily transformed by the use of 1,3-dipolar and nucleophilic addition reactions, as well as oxidative coupling, that gives a large group of new paramagnets: 2-(1H-pyrazol-5-yl)vinyl-, 2-ethynylcyclopropyl-, 2-(3-(ethoxycarbonyl) isoxazol-5-yl)vinyl-, 1-(pyrrolidin-1-yl)but-3-ynyl-substituted nitronyl nitroxide and a diradical -2,2'-((1E,7E)-octa-1,7-dien-3,5-diyne-1,8-diyl)bis(4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl). The new nitroxides were characterized by X-ray single crystal data, ESR and static magnetic susceptibility measurements |