Ten YA, Salnikov OG, Amitina SA, Stass DV, Rybalova TV, Kazantsev MS, Bogomyakov AS, Mostovich EA, Mazhukin DG. The Suzuki-Miyaura reaction as a tool for modification of phenoxyl-nitroxyl radicals of the 4
H-imidazole
N-oxide series.
RSC Adv 2018;
8:26099-26107. [PMID:
35541934 PMCID:
PMC9082764 DOI:
10.1039/c8ra05103h]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 07/13/2018] [Indexed: 11/30/2022] Open
Abstract
2-(3,5-Di-tert-butyl-4-hydroxyphenyl)-5-(4-iodophenyl)-4,4-dimethyl-4H-imidazole 3-oxide reacts with phenylboronic acid and its substituted derivatives in a cross-coupling reaction of the Suzuki-Miyaura type to form 5-biphenyl derivatives of 4H-imidazole-N-oxide. Interaction of the same compound with B2(pin)2 in the presence of PdCl2(PPh3)2 proceeds through the formation of intermediate 1,3,2-dioxoborolane and leads to the product of homocoupling: biphenyl-bis(imidazole). Oxidation of the resultant imidazoles with lead dioxide quantitatively yields stable conjugated phenoxyl-nitroxyl mono- and diradicals, which are of interest as electroactive paramagnetic materials. The crystal structure of the monoradical, 2,6-di-tert-butyl-4-[1-oxido-4-(biphenyl-4-yl)-5,5-dimethyl-1H-imidazole-2(5H)-ylidene]cyclohex-2,5-dienone, its magnetic susceptibility, EPR spectra of the obtained hybrid radicals in solution, and cyclic voltammetry characteristics of 4H-imidazoles were studied.
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