Organocatálise na síntese de arilselanil-1,2,3-triazóis: reações entre arilselanil fenilazidas com β-cetoésteres ou β-cetoamidas

Abstract

The β-enaminone-azide cycloaddition was used for the synthesis of arylselanyl-1H,1,2,3-triazole-4-carboxylates and arylselanyl-1H,1,2,3-triazole-4- carboxamides by the reaction of azidophenyl arylselenides 1 with β-ketoesters 2 or β-ketoamides 4. In this work, the cycloaddition reactions were performed under mild conditions. We described the use of Et2NH (diethylamine) as an organocatalyst in reactions between azidophenyl arylselenides 1 and β-ketoesters 2 or βketoamides 4 in the presence of DMSO as solvent in short reaction times. At first, reactions between azidophenyl arylselenides 1 with β-keto esters using Et2NH (1 mol%) as an organocatalisador and DMSO as solvent at room temperature were performed. A series of arylselanyltriazoil carboxylates 3 were obtained in good yields and in times ranging from 3 to 24h. These reactions were efficient substrates to provide a variety of the arylselanyl-1H-1,2,3-triazoles in good yields [78 - 98% (3a-o)]. Thus, the reaction times have been significantly decreased from hours to just 10 minutes by performing the reactions under microwave irradiation with the desired products in excellent yields (90 to 94%). Additionally, in order to expand the use of azidophenyl arylselenides 1, they were subjected to reactions with β-ketoamides 4 using Et2NH (5 mol%) as an organocatalisador and DMSO as solvent at room temperature. Various arylselanyltriazoil carboxamides 5 were obtained with satisfactory yields in short reaction times. Therefore, the method is efficient for a variety of substrates, providing arylselanyl-1H-1,2,3-triazoles in good yields [59 and 93% (5a-n)]. In both cases, it was possible to observe the methods effectiveness used for their reactions, since a series of compounds were obtained in satisfactory yields.