TCCA; A Mild Reagent for Decarboxylative/Dehydrogenative Aromatization of Tetrahydro-β- carbolines: Utility in the Total Synthesis of Norharmane, Harmane, Eudistomin U, I and N

Abstract

An operationally simple and efficient protocol has been devised for the synthesis of various β‐carbolines using TCCA as a mild oxidant at ambient temperature. The reaction proceeds via a tandem oxidative decarboxylation followed by dehydrogenative aromatization of tetrahydro‐β‐carboline acids. In addition, this protocol works well for the partial dehydrogenation of tetrahydro‐β‐carbolines.

Recent Insights into β-Carboline Alkaloids with Anticancer Potential

“…DHβCs: These types of alkaloids possess a tricyclic pyrido [3,4-b] indole ring as common but with partially saturated pyridine ring system, hence called as 3,4-dihydro-β-carbolines (DHβCs). These can be synthesized via Pictet-Spengler reaction followed by dehydrogenation [40]. D. THβCs: These tricyclic systems usually contain saturated pyridine ring in the tricyclic pyrido [3,4-b] indole ring system the most traditional methods to synthesize THβC frameworks are Pictet-Spengler and Bischler-Napieralski reaction.…”

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

“…A general method used for this purpose is Pictet‐Spengler reaction [35] of tryptamine derivatives and an aldehyde followed by dehydrogenation to access β‐carboline. Often, oxidative dehydrogenation requires special conditions like elemental sulfur, [36] palladium on carbon, [37] MnO 2 , [38] n Bu 4 NBr‐CHP, [39] DDQ, [40] trichloroisocyanuric acid, [41] PhI(OAc) 2 , [42] N ‐chlorosuccinimide, [43] IBX, [44a] (Figure 2) I 2 /DMSO [44b] . and DBN/Air, [45a] FeCl 3 , [45b] and activated carbon [45c] .…”

TCCA-mediated oxidative rearrangement of tetrahydro-β-carbolines: facile access to spirooxindoles and the total synthesis of (±)-coerulescine and (±)-horsfiline

“…Bathini and co-workers also reported the TCCA-mediated decarboxylative/dehydrogenative aromatization of tetrahydro-β-carbolines (THBCs), which was applied for the total synthesis of β-carboline alkaloids. 19 Veisi and co-workers developed a method to produce nitriles through the direct oxidation of the corresponding amines, alcohols, aldehydes, and benzyl halides using TCCA. 20 Thus, based on these significant findings such as bioactivity and research interest on the synthesis of spirooxindoles, we developed an efficient protocol to construct spirooxindole via oxidative rearrangement using TCCA, which is a cost effective and versatile reagent.…”