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Imine-Based Catechols and o-Benzoquinones: Synthesis, Structure, and Features of Redox Behavior

[Image: see text] Novel sterically hindered catechols of the type 3-(RN=CH)-4,6-DBCatH(2) with iminoalkyl or iminoaryl groups in the third position of the aromatic ring have been synthesized and characterized in detail. The o-benzoquinones 3-(RN=CH)-4,6-DBBQ have been synthesized by the oxidation of...

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Detalles Bibliográficos
Autores principales: Astaf’eva, Tatiana V., Arsenyev, Maxim V., Rumyantcev, Roman V., Fukin, Georgy K., Cherkasov, Vladimir K., Poddel’sky, Andrey I.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2020
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7482094/
https://www.ncbi.nlm.nih.gov/pubmed/32923776
http://dx.doi.org/10.1021/acsomega.0c02277
Descripción
Sumario:[Image: see text] Novel sterically hindered catechols of the type 3-(RN=CH)-4,6-DBCatH(2) with iminoalkyl or iminoaryl groups in the third position of the aromatic ring have been synthesized and characterized in detail. The o-benzoquinones 3-(RN=CH)-4,6-DBBQ have been synthesized by the oxidation of the corresponding catechols. The oxidation of methylimino-substituted catechol with K(3)[Fe(CN)(6)] in alkaline medium leads to the formation of two products: o-quinone and diene–dione, the product of the water addition to the corresponding o-quinone. Some o-benzoquinones react with water or methanol to yield products of water or methanol addition. A prototropic tautomerism is characteristic of catecholaldimines: a quinomethide form is observed in the case of aliphatic amine derivatives, while aryl-substituted catecholaldimines can exist both in the catechol and quinomethide forms in the crystalline state. The formation of dimeric structures motifs is observed in crystals. The electrochemical oxidation of imino-based catechols proceeds via two one-electron processes; the second wave is quasi-reversible, which is unusual for catechols.