SYNTHESIS AND BROMINATION OF 2-METALLYLTHIO-3-HYDROXYIMINOMETHYLQUINOLINE

Quinoline and its condensed analogues are an important class of heterocycles with a wide range of biological activity. Many quinoline derivatives are used as substrates in organic synthesis and molecular design of pharmacologically active substances with different effects. Its reported a number of natural compounds containing a quinoline fragment are used as drugs. The annulation of azole and azine heterocycles to the quinoline backbone expands the search for biologically active compounds in this series. The most convenient and most effective method of annulation of additional cycles to quinoline is the reaction of electrophilic intramolecular cyclization of its unsaturated derivatives with various electrophilic reagents. Therefore, the synthesis of previously unknown polycyclic quinoline derivatives is an urgent problem. The purpose of this work is to study of the regio-selectivity of the process of electrophilic intramolecular cyclization of 2-methallylthio-3-(hydroxyiminomethyl)quinoline. The model oxime was obtained by the condensation reaction of 3-formyl-2-methalylthioquinoline with hydroxylamine hydrochloride in an alcohol-alkaline medium. 2-Methallylthio-3-(hydroxyiminomethyl)quinoline has several nucleophilic centers for studying of the regioselectivity of electrophilic heterocyclization - a multiple bond of a methallyl fragment, an endocyclic nitrogen atom of quinolone cycle, an exocyclic nitrogen atom of an imino group and an exocyclic atom oxygen of ОН- group. During the bromination of such an oxime, the formations of both a linear and angular tricyclic system are possible. It was found that when brominated with a double excess of bromine in chloroform medium, the thiazole cycle is annealed to the quinoline backbone to form 1-bromomethyl-4-((hydroxyimino)methyl)-1-methyl-1,2-dihydrothiazolo[3,2-a]-quinolin-10-ium tribromide. Thus, as a result of the performed research, the 2-methallylthio-3-(hydroxyiminomethyl) quinoline was obtained and its bromination was carried out. It is proved that the bromocyclization of the model oxime occurs regio-selectively with the formation of angular tribromide of 1-bromomethyl-4 -((hydroxyimino)methyl) -1-methyl-1,2-dihydrothiazolo [3,2-a] quinolin-10-ium. This tricyclic salt has the potential to have high biological activity.