5-phosphonato-3,4-dihydropyrimidin-2(1 H )-ones: Zinc triflate-catalyzed one-pot multi-component synthesis, X-ray crystal structure and anti-inflammatory activity

Synthesis of Phosphorus(V)-Substituted Six-Membered N-Heterocycles: Recent Progress and Challenges

Heterocycles functionalized with pentavalent phosphorus are of great importance since they include a great variety of biologically active compounds and pharmaceuticals, advanced materials, and valuable reactive intermediates for organic synthesis. Significant progress in synthesis of P(O)R2-substituted six-membered heterocycles has been made in the past decade. This review covers the synthetic strategies towards aromatic monocyclic six-membered N-heterocycles, such as pyridines, pyridazines, pyrimidines, and pyrazines bearing phosphonates and phosphine oxides, which were reported from 2012 to 2022.

l-Asparagine-EDTA-amide silica-coated MNPs: a highly efficient and nano-ordered multifunctional core-shell organocatalyst for green synthesis of 3,4-dihydropyrimidin-2(1H)-one compounds

In this study, new l-asparagine grafted on 3-aminopropyl-modified Fe3O4@SiO2 core-shell magnetic nanoparticles using the EDTA linker (Fe3O4@SiO2-APTS-EDTA-asparagine) was prepared and its structures properly confirmed using different spectroscopic, microscopic and magnetic methods or techniques including FT-IR, EDX, XRD, FESEM, TEM, TGA and VSM. The Fe3O4@SiO2-APTS-EDTA-asparagine core-shell nanomaterial was found, as a highly efficient multifunctional and recoverable organocatalyst, to promote the efficient synthesis of a wide range of biologically-active 3,4-dihydropyrimidin-2(1H)-one derivatives under solvent-free conditions. It was proved that Fe3O4@SiO2-APTS-EDTA-asparagine MNPs, as a catalyst having excellent thermal and magnetic stability, specific morphology and acidic sites with appropriate geometry, can activate the Biginelli reaction components. Moreover, the environmental-friendliness and nontoxic nature of the catalyst, cost effectiveness, low catalyst loading, easy separation of the catalyst from the reaction mixture and short reaction time are some of the remarkable advantages of this green protocol.

Synthesis of 3,4-Dihydropyrimidin(thio)one Containing Scaffold: Biginelli-like Reactions

The interest in 3,4-dihydropyrimidine-2(1H)-(thio)ones is increasing every day, mainly due to their paramount biological relevance. The Biginelli reaction is the classical approach to reaching these scaffolds, although the product diversity suffers from some limitations. In order to overcome these restrictions, two main approaches have been devised. The first one involves the modification of the conventional components of the Biginelli reaction and the second one refers to the postmodification of the Biginelli products. Both strategies have been extensively revised in this manuscript. Regarding the first one, initially, the modification of one of the components was covered. Although examples of modifications of the three of them were described, by far the modification of the keto ester counterpart was the most popular approach, and a wide variety of different enolizable carbonylic compounds were used; moreover, changes in two or the three components were also described, broadening the substitution of the final dihydropyrimidines. Together with these modifications, the use of Biginelli adducts as a starting point for further modification was also a very useful strategy to decorate the final heterocyclic structure.

Sulfonated carbons from agro-industrial residues: simple and efficient catalysts for the Biginelli reaction

An eco-friendly catalyst prepared from rice husk was used to synthesize dihydropyrimidinones (DHPMs) and achieved a yield of 92%.

Synthesis of 3,4-Dihydropyrimidin-2(1H)-one-phosphonates by the Microwave-Assisted Biginelli Reaction

The synthesis of novel 3,4-dihydropyrimidin-2(1H)-one-phosphonates was elaborated by the microwave (MW)-assisted three-component Biginelli reaction of β-ketophosphonates, aromatic or aliphatic aldehydes and urea derivatives. The condensation was optimized on a selected model reaction in respect of the reaction parameters, such as the heating method, the type of the catalyst and solvent, the temperature, the reaction time and the molar ratio of the starting materials. The fast and solvent-free MW-assisted procedure was then extended for the preparation of further new 3,4-dihydropyrimidin-2(1H)-one-phosphonate derivatives starting from different aromatic aldehydes, β-ketophosphonates and urea derivatives to prove the wide scope of the process. As a novel by-product of the Biginelli-type synthesis of 3,4-dihydropyrimidin-2(1H)-one-phosphonates, the 5-diethoxyphosphoryl-4-phenyl-6-styryl-3,4-dihydropyrimidin-2(1H)-one was also isolated and characterized. Our MW-assisted method made also possible the condensation of aliphatic aldehydes, diethyl (2-oxopropyl)phosphonate and urea, which reaction was previously reported to be impossible in the literature.