Heterocyclization of polarized system: synthesis, antioxidant and anti-inflammatory 4-(pyridin-3-yl)-6-(thiophen-2-yl) pyrimidine-2-thiol derivatives

Innovation of eco-friendly TiO2 nano catalyst for new pyrimidine carbonitiriles candidates, assessed for significant antioxidant activity, anti-inflammatory effects, and by insilico studies

Production of titanium dioxide nanoparticles (TiO2- NPs) is carried out in high quantities for an extensive range of applications. These nanoparticles have various physicochemical properties, which can affect their bioactivity. The Biginelli synthesis of 4-cyanobenzaldehyde, ethyl cyanoacetate, and thiourea in the presence of TiO2 nanoparticle yields 4-(4-cyanophenyl)-6-oxo-2-thioxohexahydropyrimidine-5-carbonitrile (1). This multi-component system is safe, eco-friendly, and non-toxic. The introduction of the new system saves time and reduces chemical usage. Compound (1) underwent reactions with various additional compounds such as (methyl iodide, chloroacetonitrile, chloroacetone, acrylonitrile, ethyl chloroacetate, and chloroacetic acid/benzaldehyde). The newly synthesized compounds possess remarkable anti-inflammatory and antioxidant activities, making them an excellent choice for therapeutic use.. The in-silico studies include molecular docking using MOE, Pharmacokinetics using Toxoradar, SAR, and DFT studies.

Sustainable technology for cultural heritage preservation: The role of green corrosion inhibitors

The preservation of metallic artefacts in cultural heritage necessitates effective corrosion control strategies to ensure structural stability and aesthetic integrity. Conventional synthetic corrosion inhibitors, while demonstrating high efficacy, present significant environmental and health concerns due to their inherent toxicity. Consequently, sustainable, plant-derived corrosion inhibitors have emerged as promising alternatives, offering comparable protective performance with reduced ecological impact. This review examines the potential of plant extracts as environmentally benign corrosion inhibitors, highlighting their diverse phytochemical constituents-including tannins, alkaloids, and amino acids-which exhibit functional similarity to synthetic organic inhibitors in electronic structure and adsorption mechanisms. These bioactive compounds mitigate corrosion through adsorption, leading to the formation of protective passive layers that hinder oxidation reactions and restrict electrochemical degradation. For instance, tannic acid reacts with iron to form ferric tannates, generating a stable barrier against aggressive electrolytes. Similarly, extracts from Ceratonia siliqua and Brassica campestris have demonstrated notable corrosion inhibition for copper alloys and Cor-Ten steel, respectively. The efficacy of these plant-derived inhibitors is commonly assessed using electrochemical techniques, particularly electrochemical impedance spectroscopy (EIS), where an increase in charge-transfer resistance (Rct) and a reduction in double-layer capacitance (Cdl) indicate enhanced corrosion protection. This study presents a comprehensive evaluation of the mechanisms, performance, and applicability of green corrosion inhibitors in metallic heritage conservation, with case studies demonstrating their successful implementation in preservation efforts. Furthermore, key challenges such as optimizing inhibitor concentrations, managing temperature sensitivity, and ensuring long-term stability are critically analyzed. Additionally, various inhibitor application methods are explored along with practical considerations for scaling up and integrating green inhibitors into conservation workflows. Additionally, a comparative analysis of conventional and sustainable inhibitors in real-world applications is presented. The review concludes by highlighting key research gaps and proposing future directions for advancing plant-based corrosion inhibitor technologies in heritage conservation. Through this analysis, it seeks to enhance the understanding and adoption of sustainable corrosion mitigation strategies for preserving metallic cultural artefacts.

Discovery of Novel and Selective Schiff Base Inhibitors as a Key for Drug Synthesis, Molecular Docking, and Pharmacological Evaluation

Diabetes mellitus (DM) is a chronic disorder and still a challenge throughout the world, and therefore the search for safe and effective inhibitors for α-amylase and α-glucosidase is increasing day by day. In this work, we try to carry out the synthesis, modification, and computer-aided results of and biological research on thiadiazole-based Schiff base derivatives and evaluate their in vitro α-amylase and α-glucosidase inhibitory potential (1-15). In the current series, all of the synthesized analogues were shown to have potential inhibitory effects on targeted enzymes. The IC50 values for α-amylase values ranged from 20.10 ± 0.40 to 0.80 ± 0.05 μM, compared with the standard drug acarbose having an IC50 value of 10.30 ± 0.20 μM, while for α-glucosidase, the IC50 values ranged from 20.10 ± 0.50 to 1.20 ± 0.10 μM, compared to acarbose with an IC50 value of 9.80 ± 0.20 μM. For better understanding, a SAR investigation was undertaken. In this series, nine scaffolds (1, 2, 3, 6, 9, 10, 11, 13, and 15) were more active than the reference drug and the docking parameter RMSD values for α-glucosidase and α-amylase were 1.766, 2.7746, 1.6025, 2.2112, 3.5860, 2.3360, 1.6178, 2.0254, and 2.0797 and 2.6020, 1.9509, 3.1642, 1.7547, 2.2130, 1.4221, and 1.1087, respectively. The toxicity of the selected analogues was calculated by using the OSIRIS tool, and the TPSA values were found to be lower than 140 to represent the drug-like properties; those from Molinspiration were studied as well. The following properties were studied and found to have better biological properties. The remaining analogues (4, 5, 7, 8, 12, and 14) were also identified as potential inhibitors of both enzymes, but they were less active than the reference due to the substituents attached to the aromatic parts. The structures of synthesized compounds were confirmed through different spectroscopic analyses.

Synthesis of novel pyrazolone candidates with studying some biological activities and in-silico studies

Pyranopyrazole derivatives have a vital role in the class of organic compounds because of their broad spectrum of biological and pharmacological importance. Our current goal is the [3 + 3] cycloaddition of benzoyl isothiocyanate and pyrazolone 1 to undergo oxidation cyclization, producing pyrazoloxadiazine 3. The diol 5 was obtained as a condensation of two equivalents of 1 with thiophene-2-carboxaldehyde in acetic acid above the sodium acetate mixture. When the condensation was carried out in piperidine under fusion, unsaturated ketone 4 was obtained. The pyrazolo pyran derivative 11 resulted from the [3 + 3] cycloaddition of 1 and cinnamic acid, while the Pyrone derivative was prepared by acylation of 12 with two equivalents of acetic anhydride. Phthalic anhydride undergoes arylation using zinc chloride as a catalyst. The cyclic keto acid 23 was synthesized by the action of succinic anhydride on 12 in the acetic medium, while the latter reacted with cinnamic acid, leading to pyrazole derivative 24. All of these reactions were through the Michael reaction mechanism. All the tested compounds showed good antimicrobial activity against pathogenic microorganisms; newly synthesized compounds were also screened for their antioxidant activity. Rational studies were carried out by the ABTs method to allow a broader choice of activities. In addition, similar off-compounds were conducted. Molecular docking studies with the CB-Dock server and MD simulations were created with the default settings of the Solution Builder on the CHARMM-GUI server at 150 nm. A good correlation was obtained between the experimental results and the theoretical bioavailability predictions using POM theory.

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.

New N-Alkylated Heterocyclic Compounds as Prospective NDM1 Inhibitors: Investigation of In Vitro and In Silico Properties

A new family of pyrazole-based compounds (1–15) was synthesized and characterized using different physicochemical analyses, such as FTIR, UV-Visible, ¹H, ¹³C NMR, and ESI/LC-MS. The compounds were evaluated for their in vitro antifungal and antibacterial activities against several fungal and bacterial strains. The results indicate that some compounds showed excellent antibacterial activity against E. coli, S. aureus, C. freundii, and L. monocytogenes strains. In contrast, none of the compounds had antifungal activity. Molecular electrostatic potential (MEP) map analyses and inductive and mesomeric effect studies were performed to study the relationship between the chemical structure of our compounds and the biological activity. In addition, molecular docking and virtual screening studies were carried out to rationalize the antibacterial findings to characterize the modes of binding of the most active compounds to the active pockets of NDM1 proteins.

Visible-Light-Induced Organophotocatalytic Difunctionallization: Open-Air Hydroxysulfurization of Aryl Alkenes with Aryl Thiols

Herein, we report a regioselective visible-light-induced organophotoredox catalytic difunctionalization method to prepare β-hydroxysulfides using aryl alkenes and aryl thiols as substrates. The reaction provides a wide substrate scope of aryl alkenes (from simple styrene to complex bioactive compounds) and aryl thiols (from diverse heteroaromatic thiols to nonheteroaromatic thiols) (total 45 examples, up to 88% yield). Based on the combined experimental and computational studies, we demonstrate that in situ generated hydroperoxyl radicals from O₂ in air react with benzylic radicals, which restrains the reaction between benzylic radicals and the acidic form of thiols in a classical thiol-ene radical reaction. We show that difunctionalization is possible due to the choice of bases, diluted substrate concentrations, increment in catalyst loading, and selection of suitable aryl thiols under aerobic conditions. Considering the biological importance of heteroaromatic thiols and the lack of methods to install them, our approach offers a platform to derive various β-hydroxysulfides that contain aromatic elements.

Synthesis, screening as potential antitumor of new poly heterocyclic compounds based on pyrimidine-2-thiones

Background

Continuing our interest in preparing of new heterocyclic compounds and examining their various biological activities, this work was designed to prepare new condensed and non-condensed heterocyclic compounds 9a-c, 10a-c, 11a-c, 13a-c and 14a-c were synthesized starting with pyrimidine-2-thiones 4a-c.

Results

Thiazolo[3,2-a]pyrimidines 9a-c were synthesized by S-alkylation of pyrimidine-2-thiones,4a-c, internal cyclization in alkaline medium with ammonia, condensation with benzaldehyde and finally reaction with hydroxylamine hydrochloride.[1,2,4]thiadiazolo[4,5-a]pyrimidines 11a-c were formed by heating of the 4a-c with benzoylcholride to afford 10a-c followed by reaction with sodium hypochlorite, ammonia and sodium hydroxide. Cyclocondensation of 4a-c with ethyl acetoacetate or formic acid yielded pyrazol-3-ones 13a-c or [1,2,4] triazolo[4,3-a]pyrimidines 14a-c, respectively Elements analysis, IR, 1H-NMR, 13C-NMR and mass spectra were used to validate the structures of newly synthesized heterocycles. Screening of the selected compounds 4a, 6a, 7a, 9a, 10a, 13a and 14a against colon carcinoma cell lines (HCT-116) and hepatocellular carcinoma cell lines (HepG-2).

Conclusions

Elements analysis, IR, 1H-NMR, 13C-NMR and mass spectra were used to validate the structures of newly synthesized heterocycles. Screening of the selected compounds 4a, 6a, 7a, 9a, 10a, 13a and 14a against colon carcinoma cell lines (HCT-116) and hepatocellular carcinoma cell lines (HepG-2) showed that compound 10a exhibited the most cytotoxic, while compounds 4a, 6a and 14a exhibited considerable cytotoxic activity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13065-022-00810-4.

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.

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.

Synthesis, ADMET Properties, and In Vitro Antimicrobial and Antibiofilm Activity of 5-Nitro-2-thiophenecarbaldehyde N-((E)-(5-Nitrothienyl)methylidene)hydrazone (KTU-286) against Staphylococcus aureus with Defined Resistance Mechanisms

The emergence of drug-resistant Staphylococcus aureus is responsible for high morbidity and mortality worldwide. New therapeutic options are needed to fight the increasing antimicrobial resistance among S. aureus in the clinical setting. We, therefore, characterized the in silico absorption, distribution, metabolism, elimination, and toxicity (ADMET) and in vitro antimicrobial activity of 5-nitro-2-thiophenecarbaldehyde N-((E)-(5-nitrothienyl)methylidene)hydrazone (KTU-286) against drug-resistant S. aureus strains with genetically defined resistance mechanisms. The antimicrobial activity of KTU-286 was determined by CLSI recommendations. The ADMET properties were estimated by using in silico modeling. The activity on biofilm integrity was examined by crystal violet assay. KTU-286 demonstrated low estimated toxicity and low skin permeability. The highest antimicrobial activity was observed among pan-susceptible (Pan-S) S. aureus (minimal inhibitory concentration (MIC) 0.5–2.0 µg/mL, IC₅₀ = 0.460 µg/mL), followed by vancomycin resistant S. aureus (VRSA) (MIC 4.0 µg/mL, IC₅₀ = 1.697 µg/mL) and methicillin-resistant S. aureus (MRSA) (MIC 1.0–16.0 µg/mL, IC₅₀ = 2.282 µg/mL). KTU-286 resulted in significant (p < 0.05) loss of S. aureus biofilm integrity in vitro. Further studies are needed for a better understanding of safety, synergistic relationship, and therapeutic potency of KTU-286.

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

A versatile, efficient, clean, and facile method was used for the synthesis of pyrano[2,3-d]pyrimidine derivatives by the one-pot three-component condensation reaction of thiobarbituric acid and malononitrile with p-chlorobenzaldehyde, using Fe3 O4 or ZnO or Mn3 O4 as nanostructure catalysts. The catalyst could be easily recovered using an external magnet and reused for six cycles with almost a consistent activity. A series of polyheterocyclic compounds containing five and/or six rings fused with each other was designed. The anti-inflammatory activities for some of the newly synthesized compounds were evaluated. All the synthesized compounds were characterized on the basis of their elemental analyses and spectral data.