A convenient synthesis of pyrrolopyridines and 2-substituted indoles by gold-catalyzed cycloisomerization
作者:K.C. Majumdar、S. Samanta、B. Chattopadhyay
DOI:10.1016/j.tetlet.2008.10.013
日期:2008.12
We have developed a gold-catalyzed intramolecular cyclization of variously substituted acetylenic amines under mild conditions, which yields pyrrolopyridines and 2-substituted indoles, quantitatively. The cycloisomerization of acetylenic amines was achieved with AuCl3 as catalyst without the use of base, acid or N-protecting group.
Double Sonogashira reactions on dihalogenated aminopyridines for the assembly of an array of 7-azaindoles bearing triazole and quinoxaline substituents at C-5: Inhibitory bioactivity against Giardia duodenalis trophozoites
作者:Tlabo C. Leboho、Somnath Giri、Inessa Popova、Ian Cock、Joseph P. Michael、Charles B. de Koning
DOI:10.1016/j.bmc.2015.05.024
日期:2015.8
The synthesis of 2,3,5-trisubstituted 7-azaindoles as well as 2,5-disubstituted 7-azaindoles from 3,5-dihalogenated 2-aminopyridines is outlined. Using a double Sonogashira coupling reaction on 2-amino-3,5-diiodopyridine followed by the Cacchi reaction the synthesis of 2,3,5-trisubstituted 7-azaindoles was accomplished. In addition, using two sequential Sonogashira coupling reactions on 2-amino-5-bromo-3-iodopyridine and a potassium t-butoxide mediated ring closure reaction resulted in the assembly of 2,5-disubstituted 7-azaindoles. The 5-alkynyl substituent of the azaindole was easily converted into both quinoxaline and triazole substituents, the latter utilizing an alkyne-azide cycloaddition reaction. Some of these azaindole derivatives showed very promising biological activity against the gastrointestinal protozoal parasite Giardia duodenalis. (C) 2015 Elsevier Ltd. All rights reserved.
Regioselective synthesis of substituted pyrrolopyridines based on Pd(II)-mediated cross coupling and base induced heteroannulation
作者:K.C. Majumdar、S. Mondal
DOI:10.1016/j.tetlet.2007.07.170
日期:2007.9
Novel pyrrolopyridines have been synthesized by an efficient, regioselective and catalytic method from commercially available and inexpensive 3-aminopyridine or 2-aminopyridine. (c) 2007 Elsevier Ltd. All rights reserved.