Catalyst-Solvent System for PASE Approach to Hydroxyquinolinone-Substituted Chromeno[2,3-b]pyridines Its Quantum Chemical Study and Investigation of Reaction Mechanism.

Fedor V Ryzhkov,Michail N Elinson,Mikhail P Egorov,Yuliya E Ryzhkova,Anatoly N Vereshchagin,Artem N Fakhrutdinov,Stepan V Vorobyev

doi:10.3390/molecules25112573

Abstract

The Pot, Atom, and Step Economy (PASE) approach is based on the Pot economy principle and unites it with the Atom and Step Economy strategies; it ensures high efficiency, simplicity and low waste formation. The PASE approach is widely used in multicomponent chemistry. This approach was adopted for the synthesis of previously unknown hydroxyquinolinone substituted chromeno[2,3-b]pyridines via reaction of salicylaldehydes, malononitrile dimer and hydroxyquinolinone. It was shown that an ethanol-pyridine combination is more beneficial than other inorganic or organic catalysts. Quantum chemical studies showed that chromeno[2,3-b]pyridines has potential for corrosion inhibition. Real time 1H NMR monitoring was used for the investigation of reaction mechanism and 2-((2H-chromen-3-yl)methylene)malononitrile was defined as a key intermediate in the reaction.

Highlights

Multicomponent reactions (MCRs) employ three or more reactants to obtain heterocycles containing structures of all starting materials in a one-pot process under fixed reaction conditions [1,2,3,4]
The PASE approach has recently emerged [5,6], it is based on the Pot economy principle and unites it with the Atom and Step Economy strategies (PASE), thereby ensuring high efficiency, simplicity and low waste formation [7,8,9,10]
To examine the reaction of salicylaldehyde 1a, malononitrile dimer 2 and hydroxyquinolinone 3, we have carried out multicomponent synthesis of chromeno[2,3-b]pyridine 4a under solvent-free conditions (Scheme 1, Table 1)

Summary

Introduction

Multicomponent reactions (MCRs) employ three or more reactants to obtain heterocycles containing structures of all starting materials in a one-pot process under fixed reaction conditions [1,2,3,4]. It provides powerful productivity to satisfy modern green chemistry requirements, but new synthetic strategies with robust efficiency are still demanded In this connection, the PASE approach has recently emerged [5,6], it is based on the Pot economy principle and unites it with the Atom and Step Economy strategies (PASE), thereby ensuring high efficiency, simplicity and low waste formation [7,8,9,10]. The PASE approach has recently emerged [5,6], it is based on the Pot economy principle and unites it with the Atom and Step Economy strategies (PASE), thereby ensuring high efficiency, simplicity and low waste formation [7,8,9,10] Nowadays, it is emerging as a fast-paced research front of organic chemistry [11,12,13,14,15,16]. The development of PASE approaches to anti-corrosion heterocycles is beneficial for protection of metals

Methods

Results

Conclusion