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

Novel sterically hindered catechols of the type 3-(RNCH)-4,6-DBCatH2 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 c...

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Veröffentlicht in:ACS omega 2020-09, Vol.5 (35), p.22179-22191
Hauptverfasser: Astaf’eva, Tatiana V, Arsenyev, Maxim V, Rumyantcev, Roman V, Fukin, Georgy K, Cherkasov, Vladimir K, Poddel’sky, Andrey I
Format: Artikel
Sprache:eng
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Zusammenfassung:Novel sterically hindered catechols of the type 3-(RNCH)-4,6-DBCatH2 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 K3[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.
ISSN:2470-1343
2470-1343
DOI:10.1021/acsomega.0c02277