InCl3 mediated heteroarylation of indoles and their derivatization via C H activation strategy: Discovery of 2-(1H-indol-3-yl)-quinoxaline derivatives as a new class of PDE4B selective inhibitors for arthritis and/or multiple sclerosis
作者:Rajnikanth Sunke、Ramudu Bankala、B. Thirupataiah、E.V.V. Shivaji Ramarao、Jetta Sandeep Kumar、Hari Maduri Doss、Raghavender Medishetti、Pushkar Kulkarni、Ravi Kumar Kapavarapu、Mahaboobkhan Rasool、Jayesh Mudgal、Jessy E. Mathew、Gautham G. Shenoy、Kishore V.L. Parsa、Manojit Pal
DOI:10.1016/j.ejmech.2019.04.020
日期:2019.7
synthesized via the InCl3 mediated heteroarylation of indoles and their further derivatization through the Pd(II)-catalyzed CH activation strategy. This effort allowed us to discover a series of 2-(1H-indol-3-yl)-quinoxaline based inhibitors possessing PDE4B selectivity over PDE4D and PDE4C. One of these compounds i.e. 3b (PDE4B IC50 = 0.39 ± 0.13 μM with ∼27 and > 250 fold selectivity for PDE4B over PDE4D and
TFA alone was found to be remarkably effective for the intramolecular hydroarylation (IMHA) of alkynes when employed as a solvent in the cyclization of 3-alkynyl substituted2-(indol-3-yl)quinoxalines. This simple and metal free cyclization method afforded a range of indolophenazines as new and potential cytotoxic agents. The use of excess TFA was found to be crucial for the success of this reaction
Metal-free TFA promoted arylation/heteroarylation was achieved under mild conditions via the reaction of chloro-derivatives of nitrogen heterocycles [e. g., =C−C(Cl)=N−] with electronrich arenes/heteroarenes. It was also observed that apart from participating in the heteroarylation step, TFA was able to facilitate the hydroarylation/o-arylation process in the same pot affording the carbazole/oxepine