Ecofriendly synthesis of pyrano[2,3-d]pyrimidine derivatives and related heterocycles with anti-inflammatory activities

Silver-catalyzed regioselective synthesis of pyrano heterocycles: a versatile route to samoquasine A derivatives

This study introduces a silver-catalyzed method for the efficient and regioselective synthesis of pyrano heterocycles, utilizing readily available alcohols and water as nucleophiles. The method demonstrates high efficiency, delivering excellent yields and selectivity, and is scalable to gram quantities while maintaining broad functional group tolerance. Notably, the synthesized pyrano[3,4-c]quinolines were successfully transformed into diverse samoquasine A derivatives, underscoring the method's applicability in natural product synthesis. This work represents a significant advancement in pyrano heterocycle synthesis, offering a practical route to valuable compounds with potential applications in pharmaceutical and chemical research.

Design, synthesis, pharmacological evaluation, and in silico studies of the activity of novel spiro pyrrolo[3,4-d]pyrimidine derivatives

In the present study, spiro compounds are shown to have distinctive characteristics because of their interesting conformations and their structural impacts on biological systems. A new family of functionalized spiro pyrrolo[3,4-d]pyrimidines is prepared via the one-pot condensation reaction of amino cyclohexane derivatives with benzaldehyde to prepare fused azaspiroundecanedione and azaspirodecenone/thione derivatives. A series of synthesized spiro compounds were scanned against DPPH and evaluated for their ability to inhibit COX-1 and COX-2. All compounds exhibit significant antiinflammatory activity, and they inhibited both COX-1 and COX-2 enzymes with a selectivity index higher than celecoxib as a reference drug. The most powerful and selective COX-2 inhibitor compounds were 11 and 6, with selectivity indices of 175 and 129.21 in comparison to 31.52 of the standard celecoxib. However, candidate 14 showed a very promising antiinflammatory activity with an IC50 of 6.00, while celecoxib had an IC50 of 14.50. Our findings are promising in the area of medicinal chemistry for further optimization of the newly designed and synthesized compounds regarding the discussed structure-activity relationship study (SAR), in order to obtain a superior antioxidant lead compound in the near future. All chemical structures of the novel synthesized candidates were unequivocally elucidated and confirmed utilizing spectroscopic and elemental investigations.

Recent medicinal approaches of novel pyrimidine analogs: A review

Pyrimidine derivatives attract researchers due to their versatile scaffold & their medicinal significance. Pyrimidine associated analogs are majorly contributed to the field of medicinal chemistry. In this review article, the recent new structural design and development of active agent studies and biological approaches are highlighted. In addition, the biological potency and the structure-activity relationship of pyrimidines such as antimicrobial, anticancer, anti-inflammatory, analgesic, anti-diabetic, anti-HIV, anthelmintic, CNS depressants, and cardiac agents are discussed. Finally, this review article may attract the researchers for new structural design and development of novel active pyrimidine scaffolds with more active and less harmful.

Synthesis, pharmacological evaluation, DFT calculation, and theoretical investigation of spirocyclohexane derivatives

Polycyclic structures fused at a central carbon are of great interest due to their appealing conformational features and their structural implications in biological systems. Although progress in the development of synthetic methodologies toward such structures has been impressive, the stereo selective construction of such quaternary stereo centers remains a significant challenge in the total synthesis of natural products. From the computational calculations by Density Functional Theory along with the B3LYP as basis set, It is obvious that the all studied compounds are soft molecules and η varied from 0.069 for compound (10) to 0.087 for compound (15), while the compound (14) is treated as hard molecule, the value of η is 0.102, also the electronic transition within the soft compounds is easy as indicated from the △E, the compound (10) is absolute soft according to the (σ = 14.49 eV), while the compound (14) is treated as hard compounds (σ = 9.804 eV). The newly formed compounds exhibited both anti-inflammatory and antioxidant activities on HRBC homolytic and membrane stabilization and DPPH scavenging percent, respectively.

Importance of Hybrid Catalysts toward the Synthesis of 5H-Pyrano[2,3-d]pyrimidine-2-ones/2,4-diones (Thiones)

The pyranopyrimidine core is a key precursor for medicinal and pharmaceutical industries due to its broader synthetic applications as well as its bioavailability. Among its four possible isomers, we found that 5H-pyrano[2,3-d]pyrimidine scaffolds have a wide range of applicability, and in recent years, they have been intensively investigated, but the development of the main core is found to be more challenging due to its structural existence. In this review article, we cover all of the synthetic pathways that are employed for the development of substituted 4-aryl-octahydropyrano/hexahydrofuro[2,3-d]pyrimidin-2-one (thiones) and 5-aryl-substituted pyrano[2,3-d]pyrimidindione (2-thiones) derivatives through a one-pot multicomponent reaction using diversified hybrid catalysts such as organocatalysts, metal catalysts, ionic liquid catalysts, nanocatalysts, green solvents, catalyst-/solvent-free conditions, and miscellaneous catalysts as well as the mechanism and recyclability of the catalysts. This review mainly focuses on the application of hybrid catalysts (from 1992 to 2022) for the synthesis of 5H-pyrano[2,3-d]pyrimidine scaffolds. This review will definitely attract the world's leading researchers to utilize broader catalytic applications for the development of lead molecules.

Design, Synthesis, α-Amylase/α-Glucosidase Inhibition Assay, Induced Fit Docking Study of New Hybrid Compounds Containing 4H-Pyrano[2,3-d]pyrimidine, 1H-1,2,3-Triazole and D-Glucose Components

In this study, the click chemistry between N-propargyl derivatives of substituted 4H-pyrano[2,3-d]pyrimidines and tetra-O-acetyl-α-d-glucopyranosyl azide carried out under catalytic conditions using catalyst CuI@Montmorillonite and additive N,N-diisopropylethylamine (DIPEA). The yields of obtained hybrid compounds having 4H-pyrano[2,3-d]pyrimidine connected to 1H-1,2,3-triazole rings were about 85-94 %. All these synthesized hybrid compounds were examined for in vitro α-amylase (with IC₅₀ values in the range of 103.63±1.13 μM to 295.45±1.11 μM) and α-glucosidase (with IC₅₀ values in the range of 45.63±1.14 μM to 184.52±1.15) inhibitory activity. Amongst this series, ethyl ester 8m showed the best inhibitory activity against α-amylase with IC₅₀ of 103.63±1.13 μM, while ethyl ester 8t exhibited the highest activity against α-glucosidase with IC₅₀ of 45.63±1.14 μM. The kinetics of the inhibition of compound 8t showed the competitive α-glucosidase inhibitor property of this compound. Furthermore, the most potent compounds had any cytotoxicity against human normal cells. Induced fit docking and molecular dynamics simulation calculations indicated that the inhibition potential compounds 8m and 8t had the active interactions with the residues in receptors of corresponding tested enzymes. The calculated binding free energy from MM-GBSA approach showed that the major energy components contributed to the active binding of these studied inhibitors, including Coulomb, lipophilic and van der Waals energy. Further, 300 ns MD simulation showed that studied ligand-protein complexes were stable and indicated the structural observations into mode of binding in these complexes.

Vicia faba peel extracts bearing fatty acids moieties as a cost-effective and green corrosion inhibitor for mild steel in marine water: computational and electrochemical studies

The goal of this research is to determine what chemicals are present in two different extracts (hexane and acetone) of Vicia faba (family Fabaceae, VF) peels and evaluate their effectiveness as a corrosion inhibitor on mild steel in a saline media containing 3.5% sodium chloride. Gas chromatography-mass spectrometry (GC/MS) was used to determine the composition of various extracts. It was determined that fourteen different chemicals were present in the hexane extract, the most prominent of which were octacosane, tetrasodium tetracontane, palmitic acid, and ethyl palmitate. Heptacosane, lauric acid, myristic acid, ethyl palmitate, and methyl stearate were some of the 13 chemicals found in the acetone extract. Using open circuit potential, potentiodynamic polarisation, and electrochemical impedance spectroscopic techniques, we can approximate the inhibitory effects of (VF) extracts on mild steel. The most effective inhibitory concentrations were found to be 200 ppm for both the hexane and acetone extracts (97.84% for the hexane extract and 88.67% for the acetone extract). Evaluation experiments were conducted at 298 K, with a 3.5% (wt/v) NaCl content and a flow velocity of about 250 rpm. Langmuir adsorption isotherm shows that the two extracts function as a mixed-type inhibitor in nature. Docking models were used to investigate the putative mechanism of corrosion inhibition, and GC/MS was used to identify the major and secondary components of the two extracts. Surface roughness values were calculated after analyzing the morphology of the metal's surface with and without (VF) using a scanning electron microscope (SEM). The results showed that throughout the surface of the mild steel, a thick adsorbate layer was formed. Quantum chemical calculations conducted on the two extracts as part of the theoretical research of quantum chemical calculation demonstrated a connection between the experimental analysis results and the theoretical study of the major chemical components.

Insights into the recent progress in the medicinal chemistry of pyranopyrimidine analogs

Heterocycles containing the pyranopyrimidine motif have attracted the interest of researchers in recent decades due to their ability to synthesize and explore at a large scale to explore the biological diversity. Therefore, this review highlights the biological characteristics and synthetic approaches adopted to prepare pyranopyrimidine analogs in the last five years. Several novel preparation procedures have been summarized to synthesize these compounds using ionic, basic, or nanocatalysts or catalyst-free conditions to obtain these compounds in good yields. Pyranopyrimidines could also be used as ligands in the preparation of metal complexes with increased biological potency. The different sections include the antimicrobial, antitubercular, antimalarial, antiviral "SARS-CoV-2 inhibitors", antidiabetic, antitumor, cytotoxic, antiinflammatory, antioxidant, anticoagulant, urease inhibitory activities, and tyrosine inhibitors. The results are discussed based on the structure-activity relationships (SARs) and the mechanism of action.

Design, Synthesis, Molecular Docking, and Evaluation Antioxidant and Antimicrobial Activities for Novel 3-Phenylimidazolidin-4-One and 2-Aminothiazol-4-One Derivatives

On our way to discovering and developing compounds that have an antioxidant impact compared to ascorbic acid and other biological activities, we designed, synthesized, and evaluated a new series of heterocyclic moieties drugs (1-11) as antioxidants and antimicrobial agents. As starting moieties, these new candidates were derived from two promising heterocyclic compounds, imidazoldin-4-one and thiazol-4-one. Firstly, diphenylimidazol 1 was obtained because of the cyclo condensation one-pot ternary reaction of urea, aniline, and chloroacetic acid under thermal conditions. Out of this starting compound, we could design and create new vital rings such as purine and triazine as in compounds 5 and 6, respectively. Secondly, the start thiazole derivative 7 was obtained from the intermolecular cyclization of thiourea, chloroacetic acid, p-nitobezaldehyde in the presence of sodium acetate. We synthesized various derivatives from this second starting compound 7 by being subjected to different reagents such as aniline, phenylenediamine, phenylhydrazine, and barbituric acid to yield 8, 9, 10, and 11, respectively. Using ascorbic acid as the standard compound, the pharmacological testing for antioxidant activity assessment of the produced derivatives was evaluated against ABTS (2,20-azinobis (3-ethylbenzothiazoline-6-sulfonic acid). Candidate 6 exhibited the best activity as an antioxidant agent compared to ascorbic acid as a reference compound. Moreover, all compounds were evaluated as antimicrobial agents against a series of bacteria and fungi. Among all synthesized compounds, compound 6 achieved high efficiency against two types of fungi and four kinds of bacteria, as Clotrimazole and Ampicillin were used as the reference agents, respectively. All chemical structures of the novel synthesized candidates were unequivocally elucidated and confirmed utilizing spectroscopical and elemental investigations.

Recent advancements in the multicomponent synthesis of heterocycles integrated with a pyrano[2,3-d]pyrimidine core

Heterocyclic compounds incorporated with a pyranopyrimidine skeleton have received substantial consideration owing to their privileged, and intelligible biodiversity. Accordingly, this review highlights the multicomponent synthetic routes adopted to prepare heterocyclic compounds incorporated with the pyrano[2,3-d]pyrimidine skeleton in the preceding two years. The different sections comprise the synthesis of bicyclic, tricyclic, polycyclic, and spirocyclic systems along with the estimation of the probable mechanistic routes for the reaction pathways. Commonly, the pyran ring closure was the major idea of most studies, and the mechanistic pathways of these reactions involved Knoevenagel condensation, Michael addition, and intramolecular cyclocondensation. Besides, the significant biological potency of the compounds recently synthesized from multicomponent reactions is deliberated.

The present review highlighted the recent developments of the multicomponent synthesis of heterocyclic compounds with pyrano[2,3-d]pyrimidine skeleton applying the diverse strategies.

Three-Component Synthesis and Crystal Structure of 2-Amino-3-cyano-4H-pyran and -thiopyran Derivatives

2-Amino-3-cyano-4H-pyran and -thiopyran derivatives were synthesized by three-component reac­tions of aldehydes, dimedone, and CH acids. The molecular and crystal structures of the synthesized compounds were determined by X-ray analysis.

Synthesis, biological evaluation and induced fit docking simulation study of d-glucose-conjugated 1H-1,2,3-triazoles having 4H-pyrano[2,3-d]pyrimidine ring as potential agents against bacteria and fungi

Gluco-conjugated 1H-1,2,3-triazoles having 4H-pyrano[2,3-d]pyrimidines are synthesized via click chemistry of N-propargyl-4H-pyrano[2,3-d]pyrimidines and glucopyaranosyl azide using CuI@Montmorillonite. Their antibacterial, anti-MRSA, and antifungal activity is probed.

Design, Synthesis, Biological Evaluation, 2D-QSAR Modeling, and Molecular Docking Studies of Novel 1H-3-Indolyl Derivatives as Significant Antioxidants

Novel candidates of 3-(4-(thiophen-2-yl)-pyridin/pyran/pyrimidin/pyrazol-2-yl)-1H-indole derivatives (2–12) were designed by pairing the pyridine/pyrane/pyrimidine/pyrazole heterocycles with indole and thiophene to investigate their potential activities as (2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) inhibitors. The purpose of these derivatives’ modification is to create high-efficiency antioxidants, especially against ABTS, as a result of the efficiency of this set of key heterocycles in the inhibition of ROS. Herein, 2D QSAR modeling was performed to recommend the most promising members for further in vitro investigations. Furthermore, the pharmacological assay for antioxidant activity evaluation of the yielded indole-based heterocycles was tested against ABTS (2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid); by utilizing ascorbic acid as the standard. Candidate 10 showed higher antioxidant activity (IC₅₀ = 28.23 μg/mL) than ascorbic acid itself which achieved (IC₅₀ = 30.03 μg/mL). Moreover, molecular docking studies were performed for the newly designed and synthesized drug candidates to propose their mechanism of action as promising cytochrome c peroxidase inhibitors compared to ascorbic acid as a reference standard. Our findings could be promising in the medicinal chemistry scope for further optimization of the newly designed and synthesized compounds regarding the introduced structure-activity relationship study (SAR) in order to get a superior antioxidant lead compound in the near future.

Synthesis, DFT calculation, pharmacological evaluation, and catalytic application in the synthesis of diverse pyrano[2,3-c]pyrazole derivatives

Pyranopyrazole and its derivatives are classified to be a pharmacologically significant active scaffold for almost all modes of biological activities. In this work, An efficient, green, and facile three-component reaction for preparing pyrano[2,3-c]pyrazole derivatives via the condensation reaction of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, ethyl acetoacetate, and malononitrile in the presence of ZnO Nanoparticle. The products are produced with high yields and in shorter reaction times. It also is mild, safe, green, and environmentally friendly. The geometric parameters such as dipole moment, bond length, dihedral angles, total energy, heat of formation, atomic charges and energies at a highly accurate for prepared compounds were computed by Denisty Functional Theory along with the B3LYP functional. The newly synthesized compounds were screened for their anti-inflammatory and antioxidant activity. Some of the tested compounds displayed promising activities. The newly prepared compounds were found to be potent towards the antioxidant activity. Results indicated that compounds 11 and 12 exhibited significant (p ≥ 0.05) in vitro total antioxidant activity as 44.93 ± 0.15 and 39.60 ± 0.10 U/ML, respectively higher than standard ascorbic acid (29.40 ± 0.62).

Research developments in the syntheses, anti-inflammatory activities and structure-activity relationships of pyrimidines

Pyrimidines are aromatic heterocyclic compounds that contain two nitrogen atoms at positions 1 and 3 of the six-membered ring. Numerous natural and synthetic pyrimidines are known to exist. They display a range of pharmacological effects including antioxidants, antibacterial, antiviral, antifungal, antituberculosis, and anti-inflammatory. This review sums up recent developments in the synthesis, anti-inflammatory effects, and structure-activity relationships (SARs) of pyrimidine derivatives. Numerous methods for the synthesis of pyrimidines are described. Anti-inflammatory effects of pyrimidines are attributed to their inhibitory response versus the expression and activities of certain vital inflammatory mediators namely prostaglandin E2, inducible nitric oxide synthase, tumor necrosis factor-α, nuclear factor κB, leukotrienes, and some interleukins. Literature studies reveal that a large number of pyrimidines exhibit potent anti-inflammatory effects. SARs of numerous pyrimidines have been discussed in detail. Several possible research guidelines and suggestions for the development of new pyrimidines as anti-inflammatory agents are also given. Detailed SAR analysis and prospects together provide clues for the synthesis of novel pyrimidine analogs possessing enhanced anti-inflammatory activities with minimum toxicity.