MnO2-Mediated Oxidative Cyclization of “Formal” Schiff’s Bases: Easy Access to Diverse Naphthofuro-Annulated Triazines |
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| Authors: | Ramil F. Fatykhov Igor A. Khalymbadzha Ainur D. Sharapov Anastasia P. Potapova Nataliya N. Mochulskaya Anton N. Tsmokalyuk Alexandra V. Ivoilova Polina N. Mozharovskaia Sougata Santra Oleg N. Chupakhin |
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| Affiliation: | 1.Department of Organic and Biomolecular Chemistry, Chemical Engineering Institute, Ural Federal University, 19 Mira Str., 620002 Ekaterinburg, Russia;2.Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya Str., 620990 Ekaterinburg, Russia |
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| Abstract: | A different type of MnO2-induced oxidative cyclization of dihydrotriazines has been developed. These dihydrotriazines are considered as a “formal” Schiff’s base. This method provided easy access to naphthofuro-fused triazine via the C-C/C-O oxidative coupling reaction. The reaction sequence comprised the nucleophilic addition of 2-naphthol or phenol to 1,2,4-triazine, followed by oxidative cyclization. The scope and limitations of this novel coupling reaction have been investigated. Further application of the synthesized compound has been demonstrated by synthesizing carbazole-substituted benzofuro-fused triazines. The scalability of the reaction was demonstrated at a 40 mmol load. The mechanistic study strongly suggests that this reaction proceeds through the formation of an O-coordinated manganese complex. |
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| Keywords: | oxidative cyclization manganese(IV) oxide 1 2 4-triazine phenols cross-coupling |
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