A novel and simple strategy for the synthesis of γ-carboline

This study introduces a novel and efficient approach for the oxidative aromatization of tetrahydroγcarboline using CuCl2.2H2O and I2, H2O2 in DMSO. This method was applied for all kinds of C3 substituted tetrahydroγcarboline (THγC) units to access the corresponding aromatic γcarbolines. With a 0.25 mol% CuCl2. 2H2O as a catalyst, THγC could be efficiently oxidized to γcarboline at 100 °C with excellent yield. This protocol was also generalized for the aromatization of tetrahydroβcarboline3carboxylic acid to corresponding βcarboline3carboxylic acid. The entire synthesized new compounds were characterized by using 1HNMR, 13CNMR and Mass spectroscopy technique. To the best of our knowledge, this is the first synthesis of γcarbolines via an oxidative aromatization of THγC.