Recent Achievements in the Synthesis of Carbazole Derivatives

Carbazole derivatives possess tricyclic structure consisting of two benzene rings fused on both sides with the central pyrrole ring. These compounds diversely appear both in natural and synthetic sources. Carbazole-based compounds have a wide range of bioactivities such as antimicrobial, anticancer, antiparasitic, antihypertensive, antineuropathic, and anti-inflammatory activities. Some carbazole derivatives have been employed as drugs in the market. The synthesis of carbazole derivatives has attracted intensive interest from chemists and a huge number of studies on the synthesis of carbazole-based compounds have been published over the years. In this article, we will give a comprehensive review of studies on the synthesis of carbazoles, which date back to 2012. One hundred twenty-six studies on the synthesis of carbazoles are summarized. A huge number of novel methods have been developed to improve efficiency or employ environmentally benign procedures. In most cases, reaction mechanisms were included. The review article might be useful for chemists who work in the synthesis of heterocycles or drug chemistry.