Filak I. Electrophilic heterocyclization of 2-alkenyl(alkynyl)thio(seleno)quinoline-3-carbaldehydes.

The scientific work is devoted to the elucidation of the regularities of the reactions of electrophilic heterocyclization of alkenyl(alkynyl)-functionalized 2-thioxo(selenoxo)-quinoline-3-carbaldehydes under the action of halogens and chalcogen tetrahalides, to the development of convenient methods for the construction of azolo(azino) annelated quinolines and investigation of their biological properties. It was established the regularities of the annelation of an additional nitrogen-containing heterocycle to the quinoline backbone through the reaction of electrophilic heterocyclization under the action of halogens, depending on the nature of the substituent in the allyl fragment of the alkenyl derivatives of quinoline-3-carbaldehyde. The trihalides of thiazoloquinolines are formed during the halocyclization of terminally unsubstituted alkenylthioquinolines. The introduction of the two methyl substituents into the allyl fragment does not impact the regioselectivity of the cyclization process. The direction of the cyclization changes and the thiazinoquinolinium trihalides are formed In the case of the phenyl substituent in the allyl fragment. The chalcogene nature in position 2 of the quinoline moiety has the minimal influence on the regioselectivity of the process. The halogencyclization of propargyl-thio- and seleno-ethers of quinoline-3-carbaldehyde proceeds regio- and stereoselectively with the formation of a single configurational isomer. The regiochemistry of the electrophilic cyclization of quinoline thio- and seleno-ethers with selenium and tellurium tetrahalides depends not only on the type of alkenyl substituent but also on the nature of the chalcogen of the electrophilic reagent. The allyl thioether cyclizes with the annelation of the thiaselenazine ring under the action of selenium tetrabromide. The regioselectivity of selenobromination of quinoline-3-carbaldehyde cinnamyl thioether decreases and leads to the formation of a mixture of isomers of selenium-containing heterocycles. The introduction of the two methyl substituents to the allyl fragment of the quinoline seleno-ether moiety increases the selectivity of selenobromination. The process of tellurium-induced electrophilic cyclization of allyl, methallyl and propargyl thio-(seleno)-ethers is regioselective and leads to the formation of biologically active tellurium-containing thiazolo(selenazolo) quinolines.