[bmim(SO 3 H)][OTf]/[bmim][X] and Zn(NTf 2 ) 2 /[bmim][X] (X = PF 6 and BF 4 ); efficient catalytic systems for the synthesis of tetrahydropyrimidin-ones (-thiones) via the Biginelli reaction

Magnetic BiFeO3 nanoparticles: a robust and efficient nanocatalyst for the green one-pot three-component synthesis of highly substituted 3,4-dihydropyrimidine-2(1H)-one/thione derivatives

In this research, magnetic bismuth ferrite nanoparticles (BFO MNPs) were prepared through a convenient method and characterized. The structure and morphological characteristics of the prepared nanomaterial were confirmed through analyses using Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), elemental mapping, powder X-ray diffraction (XRD), N2 adsorption-desorption isotherms and vibrating sample magnetometry (VSM) techniques. The obtained magnetic BFO nanomaterial was investigated, as a heterogeneous Lewis acid, in three component synthesis of 3,4-dihydropyrimidin-2 (1H)-ones/thiones (DHPMs/DHPMTs). It was found that the BFO MNPs exhibit remarkable efficacy in the synthesis of various DHPMs as well as their thione analogues. It is noteworthy that this research features low catalyst loading, good to excellent yields, environmentally friendly conditions, short reaction time, simple and straightforward work-up, and the reusability of the catalyst, distinguishing it from other recently reported protocols. Additionally, the structure of the DHPMs/DHPMTs was confirmed through 1H NMR, FTIR, and melting point analyses. This environmentally-benign methodology demonstrates the potential of the catalyst for more sustainable and efficient practices in green chemistry.

Recent Advances in the Synthesis of Diverse Libraries of Small-Molecule Building Blocks in Ionic Liquids (ILs)

The Account describes recent advances, from the authors’ laboratories, in the synthesis of diverse libraries of small-molecule building blocks employing ionic liquids (ILs). The ability of ILs to act as catalysts/promoters/solvents for electrophilic and onium ion chemistry, as well as in metal-mediated cross-coupling reactions, and the potential to sequence/hyphenate these methods, have opened up new opportunities for facile assembly of functional small molecules with increased complexity from readily available precursors. While Brønsted acidic IL/IL solvent mixtures are suitable media for carbocation and onium ion chemistry, piperidine-appended IL/IL solvent mixtures can successfully catalyze a variety of base-catalyzed reactions. Several widely practiced transformations including ‘name reactions’ were adapted and performed efficiently in ILs.

1 Introduction

2 Aryldiazonium Salts and Aryltriazenes as Coupling Partners in Metal-Mediated C–C Cross-Coupling Reactions in ILs

3 Expanding the Scope of Metal-Mediated Cross-Coupling Reactions in ILs

4 Application of ILs in Synthesis and Functionalization of Hetero­cycles

5 Expanding the Scope of Amide Synthesis in ILs

6 Generation and Chemistry of ‘Tamed’ Propargylic Cations in ILs

7 Newer Nitration Methods for Arenes and Heteroarenes in ILs

8 Halofunctionalization in ILs

9 ‘Name Reactions’and Other Widely Practiced Synthetic Transformations in ILs

9.1 The Biginelli Reaction

9.2 Nitrile Synthesis by the Schmidt Reaction

9.3 Rupe Rearrangement

9.4 Synthesis of 1,3-Dioxanes via Prins Reaction in [BMIM(SO3H)][OTf]

9.5 Synthesis of Cyclopropanes and Oxiranes by the Corey–Chaykovsky (CC) Reaction

10 Conclusions and Closing Remarks

Synthesis, crystal structure and antibacterial studies of dihydropyrimidines and their regioselectively oxidized products

The syntheses and investigations of new biologically active derivatives of dihydropyrimidines by Biginelli reaction in the presence of copper triflate are reported. Due to the fact that salicylaldehyde and its derivatives under Biginelli reaction conditions can lead to the formation of 2 types of dihydropyrimidines, the influence of copper triflate on product formation was also investigated. In addition to this, regioselective oxidation of dihydropyrimidines was performed in the presence of cerium ammonium nitrate and novel oxidized dihydropyrimidines were obtained. Single crystals of some of them were obtained and as a result, the structures of them were investigated by X-ray diffraction method, which allows determining the presence of hydrogen bonds in their structures. In addition to this, the presence of hydrogen bonds in their structures affects the formation of the corresponding tautomer during oxidizing of dihydropyrimidines. Since dihydropyrimidines are claimed to be biologically active compounds, activities of the synthesized compounds were studied against Acinetobacter baumanii, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus bacteria.

Hexamethylenetetramine-based ionic liquid/MIL-101(Cr) metal-organic framework composite: a novel and versatile tool for the preparation of pyrido[2,3-d:5,6-d']dipyrimidines

In the current paper, a hexamethylenetetramine-based ionic liquid immobilized on the MIL-101(Cr) metal-organic framework was successfully synthesized as a novel, efficient, and recoverable catalyst for the synthesis of pyrido[2,3-d:5,6-d']dipyrimidine derivatives via the reaction of barbituric acid derivatives, 6-aminouracil/6-amino-1,3-dimethyl uracil, and aromatic aldehydes under solvent-free conditions. Characterization of the catalyst was carried out using various methods such as field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectrophotometry (FT-IR), and Brunauer-Emmett-Teller (BET). Efficient transformation, short reaction times, excellent yields, easy product isolation, mild conditions, and the potential high recyclability of the organocatalyst are the main features of this protocol.

Recent developments in the synthesis and applications of dihydropyrimidin-2(1H)-ones and thiones

Dihydropyrimidin-2(1H)-ones/thiones (DHPMs) are important heterocyclic compounds owing to their excellent biological activities and have been widely utilized in pharmaceutical applications. Recently, numerous DHPM derivatives have been prepared. This review covers the synthesis of DHPMs and improved procedures for the preparation of DHPMs from 1995 to 2016.