10184-98-2Relevant articles and documents
Convenient Synthesis of 6,7,12,13-Tetrahydro-5H-Cyclohepta[2,1-b:3,4-b’]diindole Derivatives Mediated by Hypervalent Iodine (III) Reagent
Peng, Lei,Zhang, Xiaofei,Yang, Chunhao
, (2019)
Bisindolyl alkaloids represent a large family of natural and synthetic products that display various biological activities. Among the bisindole compounds, 6,7,12,13-tetrahydro-5H-cyclohepta[2,1-b:3,4-b’]diindoles have received little attention. Only two methods have been developed for the construction of the 6,7,12,13-tetrahydro-5H-cyclohepta[2,1-b:3,4-b’]diindole scaffold thus far, including the classical Fischer indole synthesis conducted by reacting indole-fused cycloheptanone and hydrazines, and the condensation reaction to build the seven-membered ring. Here, we report for the first time a new route to synthesize 6,7,12,13-tetrahydro-5H-cyclohepta[2,1-b:3,4-b’]diindoles through intramolecular oxidative coupling of 1,3-di(1H-indol-3-yl)propanes in the presence of PIFA, DDQ and TMSCl with moderate to excellent yields.
Substitution of the Dimethylamino Group in Gramines and One-Pot Cyclization to Tetrahydro-β-carbolines Using a Triazine-Based Activating Agent
Fujita, Hikaru,Nishikawa, Riho,Sasamoto, Ozora,Kitamura, Masanori,Kunishima, Munetaka
, p. 8380 - 8391 (2019)
A new method for the substitution of 3-[(dimethylamino)methyl]indoles (gramines) with malonate-based nucleophiles was developed using 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) as the activating agent for the dimethylamino group. The reaction was completed in 1.5-6 h at room temperature in the presence of a tert-amine base and lithium salt. CDMT afforded superior results to methyl iodide, a common activating agent for the dimethylamino group in Mannich bases, particularly in the reactions of 1-substituted gramines. The reactivity of the possible intermediates, bis(indol-3-ylmethyl)dimethylammonium salts, was examined to obtain mechanistic insights on the reaction. This substitution method with CDMT enabled the sequential transformation of gramines: substitution with (N-alkylidene)aminomalonates followed by the Pictet-Spengler reaction under acidic conditions afforded 1,2,3,4-tetrahydro-β-carboline derivatives in one pot.
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Snyder et al.
, p. 200,203 (1944)
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