Síntese de compostos nitrogenados promovida por selênio

Abstract

In this work was developed a new and selective methodology to obtain 3-(thioaryl)-1Hindoles 3 e 2,3-di(thioaryl)-1H-indoles 4 using an oxidazing system formed by SeO2/I2 in glycerol as a green solvent. As starting materials were selected indole 1 and diphenyl disulfide 2. The reaction occurs at 100°C and the selectivety is controlled by the amount of SeO2. The use of 30 mol% of SeO2 direct the reaction in favor of products 3, on the other hand, 60 mol% allows the formation of products 4. A second part of the work was focus in the reaction of selenoamides 5 with of SmI2 (reducing agent), envisioning amines preparation. The best reaction condition was using SmI2 (6 equiv.), H2O (36 equiv.) under N2 at room temperature for 1 h. The methodology was general and allowed the preparation of 14 amines, among primary, secondary and terciary. Preliminary studies on selenoamides reductions as 5a, containing an specific pattern of substitution, has open the pathway for the use of it in radical cyclization, allowing the formation of 4,5-dibenzyl-3,4-dihydro-2H-pyrrole (7a) in moderated yield