Aromatic nucleophilic substitution: A case study of the interaction of a lithiated nitronyl nitroxide with polyfluorinated quinoline-N-oxides
By Gurskaya, Larisa; Rybalova, Tatyana; Beregovaya, Irina; Zaytseva, Elena; Kazantsev, Maxim; Tretyakov, Evgeny
Published in Journal of Fluorine Chemistry
Journal of Fluorine Chemistry
2020
Abstract
A 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl lithium derivative was found to react with 5,6,7,8-tetrafluoro- or 5,7,8-trifluoro-6-(trifluoromethyl)quinoline-N-oxides with the formation of products of aromatic nucleophilic substitution of the H atom at position 2 of the quinoline ring. The reaction regioselectivity is supported by the data of quantum-chemical calculations. Molecular and crystal structures of the obtained nitronyl nitroxides were solved by monocrystal X-ray diffraction analysis, and the nature of the radical was ascertained by electron spin resonance spectroscopy. Heterospin complexes of Cu(hfac)2 with the synthesized quinoline-substituted nitronyl nitroxides were prepared. According to X-ray diffraction analysis, seven-membered metallocycles are formed in the complexes owing to simultaneous coordination of the nitroxyl and N-oxide groups by the Cu atom.