Ultrasound-promoted regioselective synthesis of chalcogeno-indolizines by a stepwise 1,3-dipolar cycloaddition

Marcelo M Vieira; Bianca T Dalberto; Felipe L Coelho; Paulo H Schneider

doi:10.1016/j.ultsonch.2020.105228

Ultrasound-promoted regioselective synthesis of chalcogeno-indolizines by a stepwise 1,3-dipolar cycloaddition

Ultrason Sonochem. 2020 Nov:68:105228. doi: 10.1016/j.ultsonch.2020.105228. Epub 2020 Jun 23.

Authors

Marcelo M Vieira¹, Bianca T Dalberto¹, Felipe L Coelho¹, Paulo H Schneider²

Affiliations

¹ Federal University of Rio Grande do Sul (UFRGS), Chemistry Institute, Av. Bento Gonçalves 9500. CEP 91501-970, PO Box 15003, Porto Alegre, RS, Brazil.
² Federal University of Rio Grande do Sul (UFRGS), Chemistry Institute, Av. Bento Gonçalves 9500. CEP 91501-970, PO Box 15003, Porto Alegre, RS, Brazil. Electronic address: paulos@iq.ufrgs.br.

PMID: 32604055
DOI: 10.1016/j.ultsonch.2020.105228

Abstract

A series of new organochalcogen derivatives of indolizines was synthesized in moderate to excellent yields from pyridinium salts and chalcogeno-alkynes. The reaction can be carried out under thermal conditions or by sonochemical processes in short reaction times. The stepwise cycloaddition reaction forming chalcogeno-indolizines is regioselective and extends to a broad range of functional groups. Furthermore, novel chalcogeno-alkynes are reported and the first derivatives of teluro-indolizine are described. The influence of selenium functionalization on the photophysical properties of indolizines is also described, in which the compounds showed absorption in the UV-Vis region around 360 nm and emission in the blue-to-green region. Relatively low fluorescence quantum yield (ϕ_fl) values were calculated, in agreement with the chalcogen effect on other heterocycles.

Keywords: Cycloaddition; Fluorescence; Indolizines; Selenium; Ultrasound.