A Simple and Environmentally Benign Protocol for Biginelli Reactions Catalyzed by Silica-Bonded S-Sulfonic Acid

Synthesis, Molecular docking, and in silico ADME Studies of Dihydropyrimidine Derivatives using Tetrabutylphosphonium Methanesulphonate Ionic Liquid as a catalyst Under Solvent Free Conditions

This paper describes the synthesis and characterization of tetrabutylphosphonium methanesulphonate ionic liquid and its use for the first time as a catalyst in multicomponent reaction for one-pot synthesis of Dihydropyrimidine derivatives from various aromatic aldehydes, methyl or ethyl acetoacetate and urea or thio-urea under the solvent-free conditions at 120 oC. About twenty-one different dihydropyrimidine derivatives have been synthesized in excellent yields. The advantage of this method is a solvent-free condition, the requirement of a small amount of catalyst, shorter reaction time, easy workup procedure and non-involvement of any hazardous organic solvent and toxic catalyst. This catalyst was easily prepared and showed excellent level of reusability. Also the molecular docking study was performed to evaluate interactions between the active compounds with Leishmania Pteridine reductase 1(PTR1). Further the theoretical evaluation of ADME properties in silico was investigated for their oral bioavailability to predict the safer efficacy of the synthesized compounds.

1, 1'-Sulfinyldiethylammonium Bis (Hydrogen Sulfate) as a Recyclable Dicationic Ionic Liquid Catalyst for the Efficient Solvent-free Synthesis of 3, 4-Dihydropyrimidin-2(1H)-ones via Biginelli Reaction

OBJECTIVE

A facile and efficient method for synthesis of 3, 4-dihydropyrimidin-2(1H)-ones via Biginelli reaction catalyzed by a novel dicationic Brönsted acidic ionic liquid, [(EtNH2)2SO][HSO4]2, has been successfully developed.

MATERIALS AND METHODS

3, 4-Dihydropyrimidin-2(1H)-ones were synthesized through one-pot condensation of aromatic aldehydes, ethyl acetoacetate, and urea under solvent-free conditions using [(EtNH2)2SO][HSO4]2 as a novel catalyst. The progress of the reaction was monitored by thin-layer chromatography (ethyl acetate / n-hexane = 1 / 5). The products have been characterized by IR, 1H NMR, 13C NMR, and also by their melting points.

RESULTS

In this research, a library of dihydropyrimidinone derivatives was synthesized via Biginelli reaction under solvent-free conditions at 120oC using [(EtNH2)2SO][HSO4]2 as a catalyst. Various aromatic aldehydes, as well as heteroaromatic aldehydes, were employed, affording good to high yields of the corresponding products and illustrating the substrate generality of the present method. In addition, the prepared dicationic Brönsted acidic ionic liquid can be easily recovered and reused.

CONCLUSION

1, 1'-Sulfinyldiethylammonium bis (hydrogen sulfate), as a novel dicationic ionic liquid, can act as a highly efficient catalyst for the synthesis of 3, 4-dihydropyrimidin-2(1H)-ones under solvent-free conditions.

Biginelli Reaction: Polymer Supported Catalytic Approaches

The Biginelli product, dihydropyrimidinone (DHPM) core, and its derivatives are of immense biological importance. There are several methods reported as modifications to the original Biginelli reaction. Among them, many involve the use of different catalysts. Also, among the advancements that have been made to the Biginelli reaction, improvements in product yields, less hazardous reaction conditions, and simplified isolation of products from the reaction predominate. Recently, solid-phase synthetic protocols have attracted the research community for improved yields, simplified product purification, recyclability of the solid support, which forms a special economic approach for Biginelli reaction. The present Review highlights the role of polymer-supported catalysts in Biginelli reaction, which may involve organic, inorganic, or hybrid polymers as support for catalysts. A few of the schemes involve magnetically recoverable catalysts where work up provides green approach relative to traditional methods. Some research groups used polymer-catalyst nanocomposites and polymer-supported ionic liquids as catalyst. Solvent-free, an ultrasound or microwave-assisted Biginelli reactions with polymer-supported catalysts are also reported.

1,3,5-Tris(2-hydroxyethyl)isocyanurate functionalized graphene oxide: a novel and efficient nanocatalyst for the one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones

The preparation and characterization of a novel 1,3,5-tris(2-hydroxyethyl)isocyanurate functionalized graphene oxide (GO–THEIC) nanomaterial and its catalytic application for the Biginelli reaction are described.

Cu–EDTA-modified APTMS-Fe3O4@SiO2 core–shell nanocatalyst: a novel magnetic recoverable catalyst for the Biginelli reaction

A novel copper–ethylenediamine tetracarboxylate modified core–shell magnetic catalyst is introduced.

PEG-SANM nanocomposite: a new catalytic application towards clean and highly efficient Biginelli-like reaction under solvent-free conditions

The poly (ethylene glycol)-sulfonated sodium montmorillonite (PEG-SANM) nanocomposite with various ratios was prepared and used as a highly efficient and reusable solid acid nanocatalyst for synthesis of pyrimidinone derivatives under solvent-free conditions.

Aluminatesulfonic acid nanoparticles: synthesis, characterization and application as a new and recyclable nanocatalyst for the Biginelli and Biginelli-like condensations

A new, efficient and recyclable nanocatalyst, aluminatesulfonic acid, was prepared and used as a heterogeneous solid acid catalyst for the synthesis of a variety of Biginelli and Biginelli-like products under solvent-free conditions.