Heterociclos nitrogenados funcionalizados com selênio: síntese de organosselanilpirróis promovida por ultrassom e de organosselanilpiridinas utilizando Oxone ®

Abstract

In the present work, the synthesis of mono- and bisorganylselanyl-1Hpyrroles through

a multicomponent reaction between 2,5-hexanedione, primary amines and diorganyl diselenides was developed. The reaction was carried out in the presence of copper(I) iodide catalyst and under ultrasonic irradiation in DMSO as a solvent. By this efficient and simple approach, thirty-two mono- or bisorganylselenation products were obtained in moderate to excellent yields (4595%) in short reaction times (0.5 h to 4 h).

Furthermore, a green method for the synthesis of 2-aryl-(3organochalcogenyl)thieno[2,3-b]pyridines using

electrophilic chalcogen species was developed. These species were generated in situ by the reaction between diorganyl dichalcogenides and Oxone ® , using ethanol as a solvent at 78 °C. Thus, the chalcogenation/cyclization reactions of 3-(arylethynyl)-2-(alkylthio)pyridines were carried out in 2 h to 24 h, obtaining twenty-one products in good to excellent yields (70-99%). In addition, some synthetic transformations of the synthesized compounds were evaluated in oxidation, selenation and hydrogenation reactions.