SYNTHESIS OF 6,8-DINITRO-11H-INDENO[1,2-b]QUINOXALIN-11-ONE AND 1,3-DINITRO-6H-INDOLO[2,3-b]QUINOXALINE BASED ON 4,6-DINITRO-o- PHENYLENEDIAMINE

Abstract

The primary tasks of organic chemistry include the production of new nitrogen-containing heterocyclic systems. Quinoxalin derivatives are fragments of many biologically active and pharmacologically important compounds [1]: agonists and antagonists of various receptors, drugs with high antibacterial or antiviral activity [2]. In addition, they are known to be used as dyes [3], effective electroluminescent materials [4], organic semiconductors [5], "building blocks" in the synthesis of anionic receptors [6] and DNA-binding agents [7]. As part of the study, syntheses of compounds not previously described in the literature - 6,8-dinitro-11H-indeno[1,2-b]quinoxaline-1-one and 1,3-dinitro-6H-indolo[2,3-b]quinoxaline-1-one and 1,3-dinitro-6H-indolo[2,3-b]quinoxaline- were carried out. 6,8-dinitro-11H-indeno[1,2-b]quinoxalin-1-oh was obtained by the reaction of 2-amino-4,6-dinitroaniline, ninhydrin and glacial acetic acid when the mixture was heated in a boiling water bath for 6 hours and the sediment matured overnight. After filtration of the precipitate on the Schott filter, it was washed with cold isopropanol, recrystallized from ethanol, the isolated precipitate was dried at room temperature and at 60°C. 1,3-dinitro-6H-indolo[2,3-b]quinoxalin was synthesized during the reaction of 2-amino-4,6-dinitroaniline, isatin and glacial acetic acid. The mixture was heated in a boiling water bath for 9 hours. After the end of the reaction, the solution was left overnight to mature the precipitate. The next day, the sediment was filtered on a Schott filter, washed with cold isopropanol. Recrystallization was carried out from ethanol, and then the isolated precipitate was dried at room temperature and at 60°C. The structure of the obtained compounds was established using 1H, 13C NMR data and heteronuclear (HMBC, HSQC) correlation NMR spectroscopy, as well as data from elemental analysis, mass and IR spectroscopy. The developed synthesis methods are characterized by relative simplicity of execution, mild conditions, availability of reagents and allow obtaining target products with a yield of 75% (for 6,8-dinitro-11H-indeno[1,2-b]quinoxaline-11-one) and 92% (for 1,3-dinitro-6H-indolo[2,3-b]quinoxaline).