SYNTHESIS AND INTERACTION OF 4-(CINNAMYLOXY)-5,6-DIMETHYL-2-(THIOPHEN-2-YL)THIENO[2,3-d]PYRIMIDINE WITH TELLURIUM TETRAHALIDES

The work investigates the synthesis of 4-(cinnamyloxy)-5,6-dimethyl-2-(thiophen-2-yl)thieno[2,3-d]pyrimidine and its interaction with tellurium tetrachloride and tetrabromide. The synthesis of 4-(cinnamyloxy)-5,6-dimethyl-2-(thiophen-2-yl)thieno[2,3-d]pyrimidine was carried out via the alkylation reaction of 5,6-dimethyl-2-(thiophen-2-yl)thieno[2,3-d]pyrimidin-4(3H)-one in DMF in the presence of potassium carbonate with a yield of 79%. The structure of the cinnamyl ether was confirmed by spectral methods. The reactivity of the synthesized 4-(cinnamyloxy)-5,6-dimethyl-2-(thiophen-2-yl)thieno[2,3-d]pyrimidine in its interaction with tellurium tetrahalides was studied in situ. It was established that under tellurohalogenation conditions, acidolysis of the cinnamyl fragment occurs, resulting in the formation of the initial 5,6-dimethyl-2-(thiophen-2-yl)thieno[2,3-d]pyrimidin-4(3H)-one, which subsequently forms molecular complexes with tellurium tetrahalides in a 1:1 ratio. The structure and composition of the obtained adducts were confirmed by spectral methods and elemental analysis. It was shown that the nature of the tellurium-containing electrophilic reagent does not affect the reaction pathway. The obtained results expand the understanding of the reactivity of cinnamyl derivatives of thienopyrimidine and may be useful for the further synthesis of telluro-functionalized heterocyclic systems.