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ISSN 1998-9539

Synthesis, Electrochemical and Mass Spectrometric Properties of the Macrocycles with One, Two and Four 3,3´-Biindolizine Redox-Active Fragments on the 3-(Indolizin-2-yl)quinoxalin-2-one Platform

A. A. Kalinin, D. M. Rakov, L. Z. Latypova, I. Kh. Rizvanov, V. I. Morozov, V. V. Yanilkin, and V. A. Mamedov@

A.E. Arbuzov Institute of Organic and Physical Chemistry of Kazan Scientific Centre of RAS, 420088 Kazan, Russia

@Corresponding author E-mail: mamedov@iopc.ru

 

DOI: 10.6060/mhc151203m

Macroheterocycle 2016 9(1) 34-45

 

The macrocycles of large size have structural features and possess physical properties and chemical behavior different from their smaller analogues. The interest to these compounds is due to their use as drugs, selective sensors, efficient transistors, organic light-emitting diodes, solar cells. Unfortunately, the entropy of the cyclization prevents the formation of such compounds because of the large number of monomeric units and significant flexibility of acyclic oligomeric precursors, so they are very difficult to be synthesized. It is possible to allocate three approaches to the synthesis of “large macrocycles”. One of them is based on the disclosure of macrocyclic ring of smaller macrocycles, the oligomerization and subsequent closure into oligomacrocycle. Another approach is a multicomponent macrocyclization (self-assembly), resulting in the formation of a large number of bonds simultaneously. The main approach is a step-by-step synthesis. The examples of the synthesis of macrocyclic oligoanilines, oligopyridines, oligopyrroles, oligothiophenes, oligocarbazoles are known. Oligoaquinoxaline or oligoindolizine macrocycles have not been obtained. Step-by-step approach to the synthesis of the macrocycles containing 2n quinoxaline and indolizine structural units as a part of a macrocyclic skeleton has been developed. The final stage of the synthesis of macrocycles involves intramolecular dehydrocyclization of the precursors which results in the formation of the carbon-carbon bond between indolizine fragments. Three-step oxidation of biindolizine fragments are registered for the macrocycles by CVA method. The first and third stages are reversible, and the second is irreversible. Oxidation at the potentials of the first peak leads to the stable cation-radicals registered by EPR method (g = 2.0024, a2N 0.26 мТ). The fragmentation of macrocycles under the shooting conditions of MALDI mass-spectrometry measurements, unlike EI, occurs with phenyl radical ejection from the charged molecules.

 

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