An Efficient One-Pot Four-Component Synthesis of 9-Aryl-Hexahydroacridine-1,8-Dione Derivatives in the Presence of a Molecular Sieves Supported Iron Catalyst

Fe3O4@SiO2 core/shell functionalized by gallic acid: a novel, robust, and water-compatible heterogeneous magnetic nanocatalyst for environmentally friendly synthesis of acridine-1,8-diones

In this study, we conveniently prepared a novel robust heterogeneous magnetic nanocatalyst using a Fe3O4@SiO2 core/shell stabilized by gallic acid. The catalyst was completely characterized by various physicochemical techniques, including infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), potentiometric titration, energy dispersive X-ray microanalysis (EDX), vibrating sample magnetometer (VSM), zeta potential analysis, and BET. The potential ability of the newly developed sulfonated nanocatalyst was then exploited in the multicomponent synthesis of acridine-1,8-dione derivatives by considering the green chemistry matrix and under mild conditions. Various aldehydes and amines were smoothly reacted with dimedone, affording the desired products in good to excellent yields. The introduction of sulfonic groups using gallic acid allowed the development of a water-compatible and highly recyclable catalytic system for reactions in an aqueous environment. The prepared catalyst can be readily magnetically separated and reused eight times without significant loss of activity. High synthetic efficiency, using a recyclable and eco-sustainable catalyst under mild conditions, and easy product isolation are salient features of this catalytic system, which makes this protocol compatible with the demands of green chemistry.

KCC-1-nPr-NH-Arg as an efficient organo-nanocatalyst for the green synthesis of 1,8-dioxo decahydroacridine derivatives

In the present work, an innovative biocompatible heterogeneous organo-nanocatalyst is prepared based on the grafting of arginine amino acid on the channels and pores of dendritic fibrous nano silica (DFNS). The designed organo-nanocatalyst (KCC-1-nPr-NH-Arg) was characterized by using Field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDS), map analysis, and adsorption/desorption (BET-BJH) instruments. The results of analysis shown that the engineered catalyst has uniform fibrous spheres and dendritic structure with high surface area (178 m² /g) and great pore volume (0.35 cm³ .g^-1 ). Because of exceptional dendritic structure of the engineered organo-nanocatalyst, the active sites are available and the dispersion and adsorption capacity of the reagents and products increase in the pores and channels of the catalyst. Hence, KCC-1-nPr-NH-Arg was used as an capable heterogeneous basic nanocatalyst in the synthesis of 1,8-dioxo decahydroacridine derivatives from the one-pot four component reactions of aromatic aldehydes, dimedone, and ammonium acetate in solvent free conditions with shorter reaction times (13-35 min) and higher yields (94-98%) in evaluation with other reported works. It is expected that, the engineered green organo-nanocatalyst can be used to synthesize other organic compounds. This article is protected by copyright. All rights reserved.

Urease: a highly efficient biocatalyst for synthesis of polyhydroquinolines and polyhydroacridines from the ammonia formed in situ

Urease, a nickel-dependent enzyme, has a powerful catalytic activity to decompose urea into ammonia via hydrolysis reaction under mild condition. In the present work, urease was employed for the synthesis of two series of polyhydroquinoline and polyhydroacridine derivatives via one-pot condensation of the ammonia generated in situ from urea, aryl aldehydes, and dimedone or ethyl acetoacetate (i.e., Hantzsch-type reaction) in water under mild green condition. The valuable features of this enzymatic method are mild reaction conditions, short reaction times, wide substrate toleration, and high yield of products. The present work provides a novel enzymatic catalysis to synthesize polyhydroquinolines and polyhydroacridines and expands the application of urease in organic synthesis.

Facile route to synthesize Fe3O4@acacia-SO3H nanocomposite as a heterogeneous magnetic system for catalytic applications

In this work, a novel catalytic system for facilitating the organic multicomponent synthesis of 9-phenyl hexahydroacridine pharmaceutical derivatives is reported. Concisely, this catalyst was constructed from acacia gum (gum arabic) as a natural polymeric base, iron oxide magnetic nanoparticles (Fe3O4 NPs), and sulfone functional groups on the surface as the main active catalytic sites. Herein, a convenient preparation method for this nanoscale composite is introduced. Then, essential characterization methods such as various spectroscopic analyses and electron microscopy (EM) were performed on the fabricated nano-powder. The thermal stability and magnetic properties were also precisely monitored via thermogravimetric analysis (TGA) and vibrating-sample magnetometry (VSM) methods. Then, the performance of the presented catalytic system (Fe3O4@acacia-SO3H) was further investigated in the referred organic reaction by using various derivatives of the components involved in the reaction. Optimization, mechanistic studies, and reusability screening were carried out for this efficient catalyst as well. Overall, remarkable reaction yields (94%) were obtained for the various produced derivatives of 9-phenyl hexahydroacridine in the indicated optimal conditions.

The Application of 4Å Molecular Sieves in Organic Chemical Syntheses: An Overview

In the last two decades, considerable attention has been devoted to the use of 4Å molecular sieves (MS 4A) in organic chemical syntheses. Initially, they were applied as drying agents in order to dry gases, solvents and liquid reagents. Nowadays, there is a growing tendency to apply MS 4A as an additive, catalyst, co-catalyst or catalyst support in organic reactions. In this review, we aim to summarize the recent examples of organic syntheses promoted by MS 4A from 1997 to 2020. We hope to provide the reader with an overview of the potential of MS 4A in the field of organic synthesis.

1 Introduction

2 Application as an Additive

3 Application as Catalyst

4 Application as Co-catalyst

5 Application as Support

6 Conclusion

Simple and efficient synthesis of 2,2′-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives

Abstract

A simple and efficient method for the synthesis of 2,2′-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives using 4 Å molecular sieves as catalyst is described. This approach offers several advantages such as high yields, mild reaction conditions, easily accessible, and reusable catalyst, and simple work-up procedure.

Graphic abstract