Síntese de 4,7-bis-arilvinilbenzo-2,1,3 calcogenodiazóis e 4,7-bis arilcalcogeniltriazoilbenzo-2,1,3-tiadiazóis catalisada por metais de transição

Abstract

This thesis described the results about the study for synthesis of 4,7-bis arylvinylbenzo-2,1,3-calcogenadiazoles containing electron-donating and withdrawing groups in the aromatic ring. The desired products were obtained with yields ranging from moderate to excellent (65-97%) from the reaction between different styrenes or methyl acrylate with 4,7-dibromobenzocalcogendiazoles. The reaction was catalyzed by palladium acetate (10 mol%) through Heck reaction, using 4 equivalents of potassium carbonate as base, dimethylformamide as solvent, under nitrogen atmosphere at temperature of 100 ºC during 4 hours (Scheme 1). The results obtained in the synthesis of non symmetrical products will also be discussed (73-86%), through the reaction between monosubstituted compounds and styrenes (Scheme 2). All synthesized molecules were subjected to photophysical tests in collaboration with the Federal University of Santa Maria and presented satisfactory results, It is important to highlight that bisarylselanyl-benzo-2,1,3-selenadiazoles showed strong absorption bands in the UV-vis region attributed to charge transfer type transitions and red emission properties, depending on the substituent attached to the structure. The results of DNA and HSA binding studies by spectroscopic and theoretical methods of the new compounds containing chalcogen indicated a greater interaction with biomolecules. In addition, another study was carried out for synthesis of 4,7-bis arylcalcogenyltriazoylbenzo-2,1,3-thiadiazoles, using copper acetate monohydrate (Cu(OAc)2.H2O) and sodium ascorbate (NaAsc) using a cycloaddition [3 + 2] between 4,7-diethylbenzothiadiazole and arylcalcogenyl phenylazides, using a 1: 1 THF: H2O mixture as a solvent, at room temperature for 12 hours (Scheme 3). The products were obtained in yields that ranged from good to excellent (52-89%).