Graphite catalyzed solvent free synthesis of dihydropyrimidin-2(1H)-ones/thiones and their antidiabetic activity

Designing and the anticancer activity of chitosan and chitosan oligosaccharide lactate nanobeads loaded with Biginelli hybrid

This study focuses on the designing and characterization, and anticancer evaluation of chitosan-based nanoparticles (NPs) loaded (enriched) with a Biginelli hybrid compound (BH). NPs based on chitosan (CH) or chitosan oligosaccharide lactate (CHOL), are carefully designed to encapsulate a tetrahydropyrimidine derivative (BH) with already proven anticancer properties. The formulations were evaluated for their physicochemical properties, including particle size distribution and morphology, using techniques such as infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The cytotoxicity profiles were assessed on different cancer cell lines, showing a higher selectivity towards HeLa and A549 cells related to BH. BH-CH showed better cytotoxic profile related to BH-CHOL NPs. A cell cycle analysis revealed an accumulation of cells in the G2/M phase after a treatment with these NPs, indicating the ability to induce mitotic arrest in cancer cells. In summary, the results underscore the promising application of CH-based natural nanocarriers for the targeted delivery of Biginelli hybrids, showcasing a significant potential for further in vivo testing.

Novel dihydropyrimidines as promising EGFR & HER2 inhibitors: Insights from experimental and computational studies

Dihydropyrimidines are widely recognized for their diverse biological properties and are often synthesized by the Biginelli reactions. In this backdrop, a novel series of Biginelli dihydropyrimidines were designed, synthesized, purified, and analyzed by FT-IR, 1H NMR, 13C NMR, and mass spectrometry. Anticancer activity against MCF-7 breast cancer cells was evaluated as part of their cytotoxicity in comparison with the normal Vero cells. The cytotoxicity of dihydropyrimidines ranges from moderate to significant. Among the 38 dihydropyrimidines screened, compounds 16, 21, and 39 exhibited significant cytotoxicity. These 3 compounds were subjected to flow cytometry studies and EGFRwt Kinase inhibition assay using lapatinib as a standard. The study included evaluation for the inhibition of EGFR and HER2 expression at five different concentrations. At a concentration of 1000 nM compound 21 showed 98.51 % and 96.79 % inhibition of EGFR and HER2 expression. Moreover, compounds 16, 21 and 39 significantly inhibited EGFRwt activity with IC50 = 69.83, 37.21 and 76.79 nM, respectively. In addition, 3D-QSAR experiments were conducted to elucidate Structure activity relationships in a 3D grid space by comparing the experimental and predicted cytotoxic activities. Molecular docking studies were performed to validate the results by in silico method. All together, we developed a new series of Biginelli dihydropyrimidines as dual EGFR/HER2 inhibitors.

Polymer-Supported Dioxidovanadium(V) Complex-Based Heterogeneous Catalyst for Multicomponent Biginelli Reaction Producing Biologically Active 3,4-Dihydropyrimidin-2-(1H)-ones

Dioxidovanadium(V) complex [VVO2(sal-aebmz)] (1) (where Hsal-aebmz = Schiff base derived from the condensation of salicylaldehyde and 2-aminoethylbenzimidazole) has been immobilized on chloromethylated polystyrene (PS-Cl) cross-linked with divinylbenzene to obtain [VVO2(sal-aebmz)]@PS (2), a heterogeneous complex. Both complexes, after characterization, have been used as catalysts to explore a single pot multicomponent (benzaldehyde or its derivatives, urea and ethyl acetoacetate) Biginelli reaction producing biologically active 3,4-dihydropyrimidin-2-(1H)-one (DHPM)-based biomolecules under solvent-free conditions in the presence of H2O2 as a green oxidant. Various reaction conditions such as amounts of catalyst and oxidant, temperature, time, and solvent have been optimized to obtain the maximum yield of DHPMs. The polymer-immobilized complex has been found to show excellent catalytic activity, giving ca. 95% yield of DHPMs under the optimized reaction conditions selectively. Oxidant plays an important role in enhancing the yield of DHPMs.

Mild Acidic Charcoal Catalyzed Synthesis of 3,4-dihydropyrimidin-2(1H)-one/-thione Derivatives

A green and efficient method for the multicomponent synthesis of 3,4-dihydropyrimidin-2(1H)-ones and -thiones using acetic acid supported on activated charcoal as a mild acid catalyst in ethanol under both conventional as well as microwave irradiation conditions has been developed. The catalyst system found more efficient under microwave irradiation conditions than conventional conditions with shorter reaction times and excellent yields.

The Evaluation of DHPMs as Biotoxic Agents on Pathogen Bacterial Membranes

Herein, we present biological studies on 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) obtained via Biginelli reaction catalyzed by NH4Cl under solvent-free conditions. Until now, DHPMs have not been tested for biological activity against pathogenic E. coli strains. We tested 16 newly synthesized DHPMs as antimicrobial agents on model E. coli strains (K12 and R2–R4). Preliminary cellular studies using MIC and MBC tests and digestion of Fpg after modification of bacterial DNA suggest that these compounds may have greater potential as antibacterial agents than typically used antibiotics, such as ciprofloxacin (ci), bleomycin (b) and cloxacillin (cl). The described compounds are highly specific for pathogenic E. coli strains based on the model strains used and may be engaged in the future as new substitutes for commonly used antibiotics in clinical and nosocomial infections in the pandemic era.

Synthesis of dihydropyrimidinones via multicomponent reaction route over acid functionalized Metal-Organic framework catalysts

Multi component reactions over heterogeneous solid acid catalysts are extremely important owing to easy separation, amenable recycling, and prospective scaling up of the process. Here, we are reporting the synthesis of biologically important dihydropyrimidinones over postsynthetic modified Cr-based metal-organic framework materials as heterogeneous catalysts containing the bifunctional Lewis and Brønsted acid sites. Cr-based metal-organic frameworks contained coordinatively unsaturated metal sites as inherent Lewis acid sites, whereas postsynthetic modifications introduced the Brønsted acid sites in the framework. A direct one pot synthesis route was employed to produce the pristine MOF in pure aqueous medium without using any additives. The bulk structure, morphology, surface and bonding properties of the synthesized materials were thoroughly characterized with powder XRD, FTIR, XPS, FE-SEM, TGA, and N₂ sorption isotherms. A qualitative evolution of acid strength was carried out over the functionalized MOFs. Among the post synthetic functionalized materials, carboxylic acid functionalized framework exhibited a very high yield of dihydropyrimidinones under solvent less moderate reaction conditions. The catalyst also demonstrated a robust recyclability and wide substrate scope. Comparative study showed a very high catalytic activity of the postsynthetic modified MOFs in comparison to the reported literature. The reaction condition was optimized by varying parameters like solvent, temperature, reaction duration and catalyst loadings. The mechanistic studies indicated the involvement of both the Lewis and Brønsted sites acid sites of the catalysts in the multicomponent reaction.

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.

Dihydropyrimidinones Scaffold as a Promising Nucleus for Synthetic Profile and Various Therapeutic Targets: A Review

BACKGROUND

This review elaborates the updated synthetic and pharmacological approaches of a known group of dihydropyrimidinones/thiones from the multi-component reaction like Biginelli reaction, which was named Pietro Biginelli in 1891. This review consists of the reaction of an aromatic aldehyde, urea and ethyl acetoacetate leading to dihydropyrimidinone/thione. Currently, the scientific movement to develop economically viable green methods using compounds that are reusable, non-volatile, easily obtained, etc. Objective: This review covers the recent synthesis and pharmacological advancement of dihydropyrimidinones/ thiones moiety, along with covering the structure-activity relationship of the most potent compounds, which may prove to become better, more efficacious and safer agents. Thus, this review may help the researchers in drug designing and development of new Dihydropyrimidinones entities.

CONCLUSION

This review focuses on the wide application of dihydropyrimidinone/thione review reports the design, synthesis and pharmacological activities of nitrogen-sulphur containing dihydropyrimidinone moiety by using multi-component reaction. Dihydropyrimidinones (DHPM) pharmacophore is an important heterocyclic ring in medicinal chemistry. It is derived from multi-component reactions, "Biginelli reaction" and plays a critical role as anticancer, antioxidant, antimicrobial, anti-inflammatory, anti-HIV-1, antimalarial, anti-inflammatory, antihypertensive and anti-tubercular agents. Exhaustive research has led to its vast biological profile, with a wide range of therapeutic application.

One Pot Multicomponent Biginelli Reaction Employing Ionic Liquids as an Organocatalyst

Introduction:

The N-heterocyclic compounds have been extensively studied in pharmaceutical industries. Furthermore, syntheses of such compounds employing organo-catalyst have been associated with sustainable technology.

Methods:

The synthesis of new, stable ionic liquids and their catalytic applications in one-pot multicomponent Biginelli reaction is presented. The method provides broad substrate scope, yielding the corresponding 3,4-dihydropyrimidin-2(1H)-ones and 3,4-dihydropyrimidin-2(1H)-thiones, in good to excellent yields, respectively.

Results and Conclusion:

The developed reactions are associated with certain advantages, short reaction time and sustainable conditions. The protocol has advantages eco-friendly procedure, recovery and reusability of catalyst, which showed consistent activity.

An efficient synthesis of 4,5-diaryl-3,4-dihydropyrimidin-2(1H)-one via a cesium carbonate-promoted direct condensation of 1-aryl-2-propanone with 1,1′-(arylmethylene)diurea

An efficient method for the synthesis of 4,5-diaryl-3,4-dihydropyrimidin-2(1H)-one by using 1,1′-(arylmethylene)diurea and 1-aryl-2-propanone as substrates was developed. The reactions proceeded efficiently in the presence of Cs₂CO₃ to give the desired products in moderate to good yields with wide substrate scope and good functional group tolerance, serving as an attractive alternative or complement to the previously reported methods for the facile assembly of biologically and pharmaceutically active 3,4-dihydropyrimidin-2(1H)-ones.

A Cs₂CO₃-promoted efficient method for the synthesis of 4,5-diaryl-3,4-dihydropyrimidin-2(1H)-one by using 1,1′-(arylmethylene)diurea and 1-aryl-2-propanone as substrates was developed.

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.

Synthesis, Characterization, and Anticancer Activities Evaluation of Compounds Derived from 3,4-Dihydropyrimidin-2(1H)-one

3,4-dihydropyrimidin-2(1H)-one compounds (DHPMs) possess extensive biological activities and are mainly prepared via Biginelli reaction and N-alkylation. In the present study, selective alkylation of N¹ was investigated by using tetrabutylammonium hydroxide. In vitro cytotoxicity study on all synthesized compounds demonstrated that introduction of the aryl chain in the R³ as well as the low electron-donating group in the R¹ of DHPMs contributed to the anti-proliferative potency. A larger value of the partition coefficient (Log P) and suitable polar surface area (PSA) values were both found to be important in order to maintain the antitumor activity. The results from in vivo study indicated the great potential of compound 3d to serve as a lead compound for novel anti-tumor drugs to treat glioma. Pharmacophore study regarding the structure-activity relations of DHPMs were also conducted. Our results here could provide a guide for the design of novel bioactive 3,4-dihydropyrimidin-2(1H)-one compounds.

A nanocrystalline CdS thin film as a heterogeneous, recyclable catalyst for effective synthesis of dihydropyrimidinones and a new class of carbazolyl dihydropyrimidinones via an improved Biginelli protocol

An improved Biginelli protocol for the efficient synthesis of a new class of carbazolyl dihydropyrimidinones mediated by CdS thin film nanoparticles deposited on the inner walls of a glass reactor as a recyclable, heterogeneous catalyst.

Gold Catalyzed Multicomponent Reactions beyond A³ Coupling

The preparation of complex architectures has inspired the search for new methods and new processes in organic synthesis. Multicomponent reactions have become an interesting approach to achieve such molecular diversity and complexity. This review intends to illustrate important gold-catalyzed examples for the past ten years leading to interesting skeletons involved in biologically active compounds.

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.

5-Acetyl-6-methyl-4-phenyl-1-(prop-2-ynyl)-3,4-dihydropyrimidin-2(1H)-one

The 4-dihydropyrimidin-2(1H)-one moiety of the title molecule, C16H16N2O2, displays a half-chair conformation. The least-squares mean plane through this heterocycle is almost perpendicular to the aromatic ring [dihedral angle = 89.52 (8)°] and to the prop-2-ynyl chain [C—C—N—C torsion angle of −73.2 (2)°]. The mean plane through the acetyl group makes a dihedral angle of 30.93 (10)° with the mean plane of the heterocycle. There is an intramolecular C—H...O hydrogen bond forming anS(6) ring motif. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds forming inversion dimers.

Biological activity of dihydropyrimidinone (DHPM) derivatives: A systematic review

Dihydropyrimidinones are heterocycles with a pyrimidine moiety in the ring nucleus, which, in recent decades, have aroused interest in medicinal chemistry due to alleged versatile biological activity. In this systematic review, we describe the currently published activities of dihydropyrimidinone derivatives. Between 1990 and December 31st, 2016, 115 articles outlined biological activities or toxicity of DHPM derivatives, 12 of those involved in vivo experiments. The main activities associated with this class of compounds are antitumoral (43 articles), anti-inflammatory (12 articles), antibacterial (20 articles) and calcium channel antagonism/inhibition (14 articles). Antitumoral activity is the main biological property evaluated, since the main representative compound of this class (monastrol) is a known Eg5 kinesin inhibitor. This review depicts a variety of other pharmacological activities associated with DHPM derivatives, but the main findings are essentially in vitro characteristics of the substances. This review presents the current state of the art of DHPM biological activities and demonstrates that there is still a need for further in vivo studies to better delineate the pharmacological potential of this class of substances.

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.