ARYLTELLUROCHLORINATION OF 4,5-DIARYL-SUBSTITUTED 3-ALLYLTHIO-1,2,4-TRIAZOLES

Thiazolotriazole derivatives have a number of biological activities. Electrophilic intramolecular cyclization of unsaturated alkyl derivatives of 1,2,4-triazole under the action of various electrophilic reagents (halogens, tetrahalides of chalcogenides) is the most effective and simple method of synthesis of thiazolotriazoles. It was previously reported that 3-metalylthio-4,5-diphenyl-1,2,4-triazole reacts with aryltellur-trichloride to form an adduct of the substrate-electrophile composition 1: 1. Therefore, the aim of this research is to study the regioselectivity of aryltelluriumchlorination of allyl thioethers 1,2,4-triazole. It was found that in different solvents 3-allylthio-4-phenyl-5- (3-chlorophenyl) -4H-1,2,4-triazole with p-methoxyphenyltellurium trichloride forms a molecular adduct of similar composition. Instead, the addition of sodium perchlorate as doping additive to the reaction medium changes the direction of the reaction and leads to the formation of 6-(dichloro-(4-methoxyphenyl)-4-tellanyl) methyl)-5,6-dihydro-3H-thiazolo perchlorate [3,2- b][1,2,4]triazolium-7. Thus, thiazolo[3,2-b][1,2,4]triazolium salts were obtained as a result of aryl telluriumchlorination of 4,5-diaryl-substituted 3-allylthio-1,2,4-triazoles. Optimal conditions for proceeding of tellurium-induced cyclization have been found.