Synthesis of Indole Derivatives via Aryl Triazole Ring-Opening and Subsequent Cyclization
Aleksejs Burcevs,
Armands Sebris,
Irina Novosjolova,
Anatoly Mishnev,
Māris Turks
Affiliations
Aleksejs Burcevs
Institute of Chemistry and Chemical Technology, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Str. 3, LV-1048 Riga, Latvia
Armands Sebris
Institute of Chemistry and Chemical Technology, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Str. 3, LV-1048 Riga, Latvia
Irina Novosjolova
Institute of Chemistry and Chemical Technology, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Str. 3, LV-1048 Riga, Latvia
Anatoly Mishnev
Latvian Institute of Organic Synthesis, Aizkraukles Str. 21, LV-1006 Riga, Latvia
Māris Turks
Institute of Chemistry and Chemical Technology, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Str. 3, LV-1048 Riga, Latvia
A metal-free two-step synthetic approach for obtaining indole derivatives from aryl triazole fragment-containing compounds has been developed. In the first step, the Dimroth equilibrium, followed by nitrogen extrusion, Wolff rearrangement, and amine nucleophile addition, leads to the formation of N-aryl ethene-1,1-diamines. In the second step, the latter intermediates are cyclized into the target 1H-indoles in the presence of iodine. The developed method ensures the synthesis of indoles that possess N-substituents at the indole C2 position. Depending on the applied N-nucleophile, the indolization step provides a selectivity either towards 1H-indoles or 1-aryl-1H-indoles.
