Eco-friendly approach to access of quinoxaline derivatives using nanostructured pyrophosphate Na2PdP2O7 as a new, efficient and reusable heterogeneous catalyst

Karim Dânoun,Othmane Amadine,Mohamed Zahouily,Younes Essamlali,Hassan Mahi

doi:10.1186/s13065-020-0662-z

Abstract

In the present study, we report the synthesis of various quinoxaline derivatives from direct condensation of substituted aromatic 1,2-diamine with 1,2-dicarbonyl catalyzed by nanostructured pyrophosphate Na2PdP2O7 as a new highly efficient bifunctionalheterogeneous catalyst. The quinoxaline synthesis was performed in ethanol as a green and suitable solvent at ambient temperature to afford the desired quinoxalines with good to excellent yields in shorter reaction times. Many Quinoxaline derivatives were successfully synthesized using various 1,2-diketones and 1,2-diamines at room temperature. Catalyst reusability showed that the Na2PdP2O7 catalyst exhibited excellent recyclability without significant loss in its catalytic activity after five consecutive cycles.

Highlights

Quinoxaline and its derivatives are an important class of heterocyclic compounds, they have attracted considerable attention over the years owing to their very interesting pharmaceutical and biological properties such as insecticidal, antifungal, anthelmintic, anticancer, antibacterial and antiviral [1,2,3,4,5,6]
Dânoun et al BMC Chemistry (2020) 14:6 liquid 1-n-butylimidazolium tetrafluoroborate [25], zirconium tetrabis(dodecylsulfate) [26], palladium(II)acetate [27], gallium(III) triflate [28] and molecular iodine [29]. These catalytic systems suffer from several drawbacks, mainly, the drastic reaction conditions such as, high reaction temperature, high catalyst amount, prolonged reaction time even under microwave or ultrasound irradiation, contamination of the product even after purification, and it is impossible to regain the costly catalyst for reuse [30, 31], as well as the environmental pollution caused by the use of a considerable amount of toxic solvents, making the process more complicated, expensive, and environmentally unfriendly
The development of sustainable protocols to design new reusable and efficient heterogeneous catalytic systems that could be used in cleaner process has attracted tremendous interest, and numerous heterogeneous catalytic systems have been reported to be successful for the synthesis of quinoxaline derivatives

Summary

Introduction

Quinoxaline and its derivatives are an important class of heterocyclic compounds, they have attracted considerable attention over the years owing to their very interesting pharmaceutical and biological properties such as insecticidal, antifungal, anthelmintic, anticancer, antibacterial and antiviral [1,2,3,4,5,6]. ZnO-KIT-6 [32], Ni-nanoparticles [33], Yb/NaY zeolite [34], Al2O3 [35], graphene oxide [36], nanocrystalline CuO [37], NanoTiO2 [38], montmorillonite K-10 [18] Another type of materials based on metal phosphates and pyrophosphates are good candidates for the catalysis of numerous reactions requiring acidic catalysts. The structural, textural, surface and morphological properties of the prepared nanocatalysts, reaction conditions and the nanocatalyst reusability were carefully studied

Objectives

Results

Conclusion