One‐Pot Synthesis of Functionalized Carbazoles and β‐Carbolines via Diethyl Azodicarboxylate Mediated Dehydrogenative Aromatization in Deep Eutectic Solvent.

Herein we report a one‐pot approach for the functionalized carbazoles and β‐carbolines via Fischer indole/Pictet‐Spengler type reactions followed by diethyl azodicarboxylate (DEAD) mediated dehydrogenative aromatization using Deep Eutectic Solvent (N,N'‐Dimethyl urea and L‐tartaric acid combination) as reaction medium. This one‐pot method enables the synthesis of library of compounds of carbazoles and β‐carbolines with good to excellent yields in short reaction times. The developed method was extended for the copper‐mediated reaction to minimize the amounts of DEAD required. Also, the application of gram scale reaction and reusability of the DES (in both cases) is demonstrated efficiently. [ABSTRACT FROM AUTHOR]