Visible-Light-Mediated Regioselective C3-H Selenylation of Pyrazolo[1,5-a]pyrimidines Using Erythrosine B as Photocatalyst

A visible-light-induced efficient methodology has beendevelopedfor the C-H selenylation of pyrazolo[1,5-a]pyrimidine derivatives employing erythrosine B as the photocatalyst.This is the first report on the regioselective selenylation of pyrazolo[1,5-a]pyrimidines. The efficiency of this methodology for theselenylation of different electron-rich heterocycles like pyrazole,indole, imidazo[1,2-a]pyridine, imidazo[2,1-b]thiazole, and 4-(phenylamino)-2H-chromen-2-onehas been also demonstrated. The exploration of erythrosine B as aphotocatalyst with a simple and mild procedure, wide substrate scope,and practical applicability and the employment of eco-friendly energy,oxidant, and solvent are the attractive characteristics of this methodology.

Automated summary

An efficient visible-light-induced methodology using erythrosine B as the photocatalyst has been developed for the regioselective selenylation of pyrazolo[1,5-a]pyrimidine derivatives. The methodology has also been demonstrated to be efficient for selenylation of different electron-rich heterocycles. The use of erythrosine B as the photocatalyst, along with the simplicity of the procedure and the eco-friendly energy, oxidant, and solvent employed, are attractive characteristics of this methodology.