The use of arylseleninic acids in the synthesis of 4-selanylanilines, 3-selanylindoles, and 2-substituted oxazole-5-carbaldehydes

Abstract

In this thesis, are presented the results of two new methodologies using arylseleninic acids as a selenylating agent. The first work describes the use of arylseleninic acids as electrophilic selenium source, in the reaction with different N,N-dialkyl-anilines and with indole. The desired products 4-selanylanilines 1a-n and 3-selanylindoles 2a-e were achieved in good to excellent yields after 6-15 hours of reaction, at 70 °C in DMF as solvent. In the second work it is reported the cyclization of N-propargylamides mediated by visible light and promoted by benzeneseleninic acid. Twelve 2- substituted oxazole-5-carbaldehydes 8a-l were formed in 30-90% yield, and six of them were unprecedented at the time they were synthesized. This method is metal-, oxidant- and heating-free, and water and diphenyl diselenide, which can be recovered and reused, are the only waste products.