Synthetic routes for N-arylation of carbazole derivatives and their applications as organic materials

Carbazole is a heterocyclic aromatic organic compound that has vast applications in pharmaceuticals, and in biological and material sciences. Carbazole derivatives show various biological activities such as antibiotic, anti-inflammatory, anti-tumor and anti-oxidant activities etc. Synthesis of N-arylated carbazoles has become a major area of interest for scientists due to their applications in organic light-emitting diodes, dye-sensitized solar cells, and other organic electronics. The N-arylated carbazoles have unique properties such as high thermal stability, wide band gap, and excellent electrical and optical properties. The methods used for the N-arylation of carbazoles include transition metal-catalyzed reactions and metal-free reactions. The most common and classical methods for the N-arylation of carbazoles are copper-catalyzed Ullmann coupling reactions, while palladium, nickel, and iron catalysts are also used. This review focuses on all the synthetic methods used for the N-arylation of carbazoles and their applications.