Highly Selective Synthesis of 2-Amino-4,6-diarylpyridine Derivatives by the Cascade Reaction of 1,1-Enediamines with α,β-Unsaturated Ketones

Abstract

A general and concise method was developed for the synthesis of 2-amino-4,6-diarylpyridine derivatives 4−6 through the cascade reaction, which includes Michael addition, intramolecular cyclization, aromatization, and/or loss of HNO 2 , of different types of α,β-unsaturated ketones 1 and 1,1-enediamines 2 and 3 in 1,4-dioxane promoted by the base Cs 2 CO 3 or piperidine. This method is suitable for the efficient parallel synthesis of pyridines. A library of highly functional 2-amino-4,6diarylpyridine derivatives was easily constructed using the cascade reaction described in this study.

Recent advances in the transition metal-free synthesis of heterocycles from α,β-unsaturated ketones

“…The metal free methodology proceeds through a cascade of Michael addition, intramolecular cyclization, aromatization and/or loss of HNO 2 (Scheme 25). 41…”

Efficient multicomponent synthesis of 2-aminopyridines catalysed by basic mesoporous materials

“…In recent years, the challenge in organic synthesis has been the development of new MCRs using catalytic systems as well as MCM-41, clean, environmentally benign, efficient basic recyclable catalysts for the synthesis of heterocyclic compounds [16][17][18]. The structures of 2aminopyridines and its derivatives are a class of nitrogen heterocyclic compounds that have drawn much attention, due to their biological and pharmaceutical activities [19][20][21][22][23][24]. The development of clean synthetic routes towards nitrogen-containing heterocycles is of great importance to both synthetic and medicinal chemists [25][26][27].…”

Fe(OTf)3-catalyzed annulation of α,β-unsaturated ketoxime acetates with enaminones for the synthesis of functionalized 2,4-diarylpyridines

“…18 This method provides a new approach for synthesizing 2,4-diarylpyridines from ketoxime acetates, and paves the way for synthesizing heterocyclic compounds with diverse structures from ketoxime acetates. Additionally, the condensation of ketoxime acetates with α,β-unsaturated aldehydes catalyzed by Cu/iminium 19 and the cyclization of ketoxime with tertiary anilines 20 and other compounds 21 were achieved. These methods have made significant contributions to the synthesis of 2,4-diarylpyridines.…”