Arylnaphthoquinones. 8. Synthesis of 6-arylbenzo[a]phenazines

Abstract

Quinonoid compounds widespread in wildlife are involved in many biological processes and are extremely important for almost every living organism. On the other hand, the features of the structure of quinones cause a wide range of their chemical transformations. They are active in many homolytic and heterolytic reactions capable of cycloaddition. A practically important group of reactions leading to the formation of heterocyclic compounds with nitrogen atoms in the cycle is the interaction between benzo- and naphthoquinones and aliphatic and aromatic diamines as well as their derivatives. However, among the condensed nitrogen-containing heterocycles there were found practically useful substances for which anticancer, antiparasitic, antimicrobial and other biological activities were recorded. For example, the main representatives of the group of arylamine dyes are derivatives of phenazine, phenothiazine and phenoxazine. Phenazines are also widely used in the field of organic electronics, in particular, they are integrated into solar cells and OLED devices. Possibility of preparation of angular heterocyclic systems based on 3-aryl-1,2-naphtho-quinones were investigated. The 3-aryl-1,2-naphthoquinones 1–6 (аryl = 4-ClC 6 H 4 (1), 4-BrC 6 H 4 (2), 3-NO 2 C 6 H 4 (3), 4-NO 2 C 6 H 4 (4), 2,5-Cl 2 C 6 H 3 (5), 3,4-Cl 2 C 6 H 3 (6)) were obtained by means of the reaction between arenediazonium salts and 1,2-naphthoquinone under Meerwein reactions conditions. The reactions were carried out in formic acid – water medium in the presence of sodium acetate and catalytic amounts of copper salts. The yields of arylnaphthoquinones 1–6 are in range of 20–50 %. The reaction of 3-aryl-1,2-naphthoquinones 1–6 with benzene-1,2-diamine led to the formation of fused angular heterocyclic systems of 6-arylbenzo[ a ]phenazines 7–12 in high yields. The structures of the synthesized compounds were verified by the 1 H NMR spectroscopy and element analysis data. Key words: 1,2-naphthoquinone, benzene-1,2-diamine, 3-aryl-1,2-naphthoquinones, Meerwein arylation reaction, benzo[ a ]phenazines.