MnO2-Mediated Oxidative Cyclization of “Formal” Schiff’s Bases: Easy Access to Diverse Naphthofuro-Annulated Triazines

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 20; p. 7105
• Main Authors: Fatykhov, Ramil F., Khalymbadzha, Igor A., Sharapov, Ainur D., Potapova, Anastasia P., Mochulskaya, Nataliya N., Tsmokalyuk, Anton N., Ivoilova, Alexandra V., Mozharovskaia, Polina N., Santra, Sougata, Chupakhin, Oleg N.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 21-10-2022; MDPI
• Subjects: 1,2,4-triazine; Carbazole; Carbazoles; cross-coupling; Cyclin-dependent kinases; Hydrocarbons; Investigations; Manganese; Manganese dioxide; manganese(IV) oxide; oxidative cyclization; Phenols; Triazine
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27207105

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.