Síntese de selanil-imidazo[2,1-b]tiazóis e selanil-imidazo[1,2- a]piridinas utilizando Oxone®

Abstract

In the present work, a fast and efficient methodology for the synthesis of different selanil-imidazo[2,1-b]thiazoles 3a-n was developed by the use of different imidazothiazoles 1a-g and diorganyl diselenides 2a-h in the presence of Oxone® (2 equiv.) (Scheme 1, equation I). The reactions were conducted at 60 °C under open atmosphere, using acetonitrile as the solvent for a period of 2 hours. This methodology proved to be efficient for a variety of substrates, providing 14 different selanil-imidazo[2,1-b]thiazoles 3a-n in yields ranging from 62 to 95%. This synthetic methodology was also extended to imidazopyridines 4a-c under the same reaction conditions, to produce the 3-selanil-imidazo[1,2- a]pyridines 5a-c in yields from 76% to 83% (Scheme 1, equation II). Besides that, the use of sonochemistry for some examples was investigated as a tool for rapid and efficient energy transfer, which significantly reduced the reaction time to a maximum of 30 minutes for the examples tested.