N-Heterociclos funcionalizados com Enxofre e Selênio: Síntese de 1,3 benzosselenazóis 2-acilsubstituídos e bis-4,7-arilcalcogenil benzo-2,1,3 calcogenadiazóis

Abstract

In this thesis the results of synthesis studies of new N-heterocycles functionalized with sulfur and selenium will be reported. Firstly, will be described the results of one-pot synthesis of 1,3-benzeneselenazoles 2-acyl substituted 3a-1 from in situ formation of 1a '-l' glyoxal from different aryl methyl ketones 1a-1, with the bis(2-aminophenyl) diselenide 2, mediated by Na2S2O5. Two reaction methodologies were developed: conventional oil bath heating (Method A) and microwave irradiation (Method B). In both methods the desired products were obtained in yields from moderate to excellent (Scheme 1) The second paper refers to the efficient study of coupling reactions for the synthesis of bis-4,7-arylcalcogenyl benzo-2,1,3-thiadiazoles 6a-h and 8a-d, using copper species (CuO NPs and CuI) from 4,7-dibromobenzothiadiazole 4 and arylthios 5a-h or diaryl diselenide 7a-d, using KOH as base and DMSO as solvent. The desired products were obtained in good to excellent yields (69 90%) (Scheme 2). Photophysical characterization studies, such as absorption and light emission (UV-Vis) and solvatochromic effect evaluation, were developed. Scheme 2. The last methodology described in this thesis is also related to coupling reactions for the synthesis of the bis-4,7-arylselanyl benzo-2,1,3-selenadiazoles 10a-i, using CuO NPs as catalyst, from the substrates, 4,7 dibromobenzoselenadiazole 9 and diorganoyl diselenide 7a-i, using KOH as base and DMSO as solvent. The products were obtained in moderate to good yields (43-86%) (Scheme 3). Photophysical characterization tests, such as absorption and light emission (UV-Vis) were developed with all the molecules synthesized in this work. Scheme 3.