One-pot, regioselective synthesis of functionalized indole derivatives: a three-component domino reaction of arylamine, arylglyoxal, and 4-hydroxycoumarin or 4-hydroxy-6-methyl-2-pyrone

Hossein Mehrabi, Fatemeh Dastouri, Sara Asadi, Farzaneh Alizadeh-Bami, Reza Ranjbar-Karimi
2020 ARKIVOC  
A metal free, one-pot tandem synthetic routes for functionalized indole derivatives has been established. An efficient three-component reaction was designed with incorporation of Knoevenagel condensation followed by inter-, and intramolecular nucleophilic addition reaction in one-pot under mild condition. The structural diversities of the synthesized compounds have been confirmed spectroscopically, by IR, 1 H-and 13 C NMR, and elemental analyses which agree with the proposed structures. Figure
more » ... . Selected examples of bioactive indolyl chromene and indolyl pyran derivatives. Therefore, studies on strategies for the synthesis of indole derivatives have received high importance in organic synthesis. In this regard, there are many traditional methods for the preparation of indole derivatives including Fischer reaction, 18, 19 Bischler reaction, 20 Reissert reaction, 21 Bartoli reaction, 22 and Leimgruber-Batcho reaction. 23 Recently, new strategies have been developed for the synthesis of indole derivatives; these include: various metal-catalyzed, 24-29 multi-component method, 30 cyclization reaction, 31 Wittig reactions, 32 and various other methods. [33] [34] [35] [36] Most of these protocols appear to suffer from some drawbacks such as tedious experimental procedures, difficult reaction conditions, multiple synthetic steps, low yields, and usage of expensive catalysts and reagents. Therefore, the development of more economic, convenient and efficient approaches to the regioselective synthesis of substituted indoles under mild conditions is still an attractive proposition. In continuation of our previous works on the application of arylglyoxal in synthesis of heterocyclic compounds, 37,38 we herein report new synthetic strategy for the domino arylamine, arylglyoxal, and 4hydroxycoumarin or 4-hydroxy-6-methyl-2-pyrone yielding the synthesis of functionalized indole derivatives with high yields.
doi:10.24820/ark.5550190.p011.151 fatcat:iwiu6paskbgmthqn2ilmkistga