Chalcogenation Of Indole

Abstract

Organoselenium compounds are organic chemical compounds containing C-Se bond, and selenium belongs to group 16 (known as chalcogens) in the periodic table of elements. Selenium is important for being an essential component for maintaining human health especially for enhancement of the immune system, increasing thyroid health, and prevention of occurrence of numerous types of tumors. Organic diselenides (R−Se−Se−R) are the selenium equivalents of peroxides and disulfides. They are useful to make more reactive organoselenium reagents like selenols and selenenyl halides because it is characterized by its high stability. Indole is an aromatic, heterocyclic organic compound with a bicyclic structure which consists of a benzene ring and pyrrole ring. It has the formula C_8 H_7 N. The importance of functionalization of indole is because it is essential ingredients for many medicines that used for treatments of cancer, migraines, convulsions, viruses, etc. Diphenyl diselenide has been used with success to obtain seleno-indole derivatives. The objective of this project is to explore a method for direct chalcogenation on C-H bond of indole. In my research, two methods are explored to study the selenation of indole. The first synthetic method involves two steps: the synthesis of diaryl diselenides (ArSeSeAr) followed by the selenation reaction between ArSeSeAr and indole promoted by I_2 and DMSO. While the second method involves a one-pot three-component selenation reaction of indole with elemental Se powder and aryl iodides (ArI) catalyzed by copper catalyst. The selenation occurs exclusively at the 3-position of indole unit. The products are characterized by NMR spectroscopy.