Pyridine Derivatives Research Articles

A SAR Study on a Class of 6-(Trifluoromethyl)-pyridine Derivatives as RORγt Inverse Agonists

Background: The nuclear retinoic acid-related orphan receptor γt (RORγt) is an important transcription factor in immune cells. Functionally, RORγt plays an important role in promoting the differentiation of T helper 17 cells and regulating the expression of proinflammatory factors, such as interleukin 17. Therefore, RORγt is considered a promising target for the treatment of the autoimmune disorder. Currently, 21 RORγt inverse agonists with various scaffolds have entered clinical trials. Objective: To discover novel and potent RORγt inverse agonists, a series of novel 6-(trifluoromethyl) pyridine derivatives were designed and synthesized. Methods: We designed and synthesized a series of potent RORγt inverse agonists W1~W16 based on VTP-43742. Molecular docking, molecular dynamics (MD) simulation, and MM/GBSA were used to study the structure-activity relationship (SAR) of the derivatives. Results: The biological activity evaluation indicated that the target compounds showed potent RORγt inhibitory activity. The most active compound, W14, exhibited low nanomolar inhibitory activity (IC50 = 7.5 nM) in the luciferase reporter assay, which was superior to the clinical compound VTP-43742. Analysis of the binding mode of W14 demonstrated that the interaction of -CF3 with Leu324, Leu396, and His479 has an important contribution to the binding. Furthermore, W14 broke the H-bond formed by His479 and Tyr502 via a “push-pull” mechanism. Conclusion: Compound W14 could be used as a potential RORγt inverse agonist for further modification.

Current Market Potential and Prospects of Copper-based Pyridine Derivatives: A Review.

Nicotine, minodronic acid, nicotinamide (niacin), zolpidem, zolimidine, and other pyridine-based chemicals play vital roles in medicine and biology. Pyridinecontaining drugs are widely available on the market to treat a wide range of human ailments. As a result of these advances, pyridine research is continually expanding, and there are now higher expectations for how it may aid in the treatment of numerous ailments. This evaluation incorporates data acquired from sources, like PubMed, to provide a thorough summary of the approved drugs and bioactivity data for compounds containing pyridine. Most of the reactions discussed in this article will provide readers with a deeper understanding of various pyridine-related examples, which is necessary for the creation of copper catalysis-based synthetic processes that are more accessible, secure, environmentally friendly, and practical, and that also have higher accuracy and selectivity. This paper also discusses significant innovations in the multi-component copper-catalyzed synthesis of N-heterocycles (pyridine), with the aim of developing precise, cost-effective, and environmentally friendly oxygenation and oxidation synthetic methods for the future synthesis of additional novel pyridine base analogs. Therefore, the review article will serve as a novel platform for researchers investigating copperbased pyridine compounds.

Unveiling the anticancer potential of novel spirooxindole-tethered pyrazolopyridine derivatives

In the current medical era, human health is confronted with various challenges, with cancer being a prominent concern. Therefore, enhancing the therapeutic arsenal for cancer with a constant influx of novel molecules that selectively target tumor cells while displaying minimal toxicity toward normal cells is imperative. This study delves into the antiproliferative and EGFR kinase inhibitory activities of newly reported spirooxindole-pyrazolo[3,4-b]pyridine derivatives 8a-h and 10a-h. The inhibitory effects on the growth of human cancer cell lines A-549 (lung carcinoma), Panc-1 (pancreatic carcinoma), and A-431 (skin epidermoid carcinoma) were evaluated, and the SAR has been clarified through analysis. With IC50 values in the single-digit micromolar range, compounds 8b, 8d, 10a-b, and 10d were shown to be the most effective antiproliferative candidates against the studied cancer cell lines. They also exerted negligible cytotoxicity (with selectivity scores between 8.63 and 30.02) against the human lung MRC5 cell line. Additionally, we investigated the potential inhibitory action of compounds 8b, 8d, 10a-b, and 10d on EGFR and VEGFR-2. 10a was this investigation’s most effective EGFR inhibitor, with an IC50 value of 0.54 μM. Ultimately, the molecular docking analysis of congener 10a highlighted its effective suppression of EGFR by examining its binding mode and docking score compared to Erlotinib. These findings underscore the potential of spirooxindole-pyrazolo[3,4-b]pyridine derivatives as promising anticancer agents targeting EGFR kinase.

Synthesis and comparative anticancer studies of Novel amide functoinalised thienopyridine and pyridothienopyrimidinone derivatives

Amide functionalized trifluoromethyl thieno[2,3-b] pyridine derivatives as a series were prepared starting from reaction between 1,3 di-ketone and thiocyanoacetamide. Compound 3 reacts with bromoethyl acetate to give compound 4. Compound 4 on reaction with diverse substituted aromatic and aliphatic amines gives amide derivatives 5a-f and these amide derivatives on reaction with triethylorthoformate give pyridothienopyrimidinone derivatives 6a-f. All the final compounds were evaluated for anti cancer activity against four human cancer cell lines such as A549—Lung cancer (CCL-185), MCF7—Breast cancer (HTB-22), DU145—Prostate cancer (HTB-81) and HeLa—Cervical cancer (CCL-2) by using MTT assay. Promising compound 5d was identified.

Biodegradation of 3-methylpyridine by an isolated strain, Gordonia rubripertincta ZJJ

Methylpyridines are a class of highly toxic pyridine derivatives. In this study, a novel degrading bacterium was isolated for 3-methylpyridine (3-MP) degradation (Gordonia rubripertincta ZJJ, GenBank accession NO. OP430847.1; CCTCC M 2022975). The maximum specific degradation rate, half-saturation constant and inhibition constant were fitted to be 0.48 h−1, 88.3 mg L−1 and 924.0 mg L−1, respectively. During 3-MP biodegradation, the lost total organic carbon was transformed into CO2 (67.4 %) and biomass (32.6 %), and ammonia nitrogen was almost the sole inorganic species with a conversion rate of 36.3 %. Three metabolic pathways were possibly involved in 3-MP degradation: I) methyl oxidation followed by ring hydroxylation and hydrogenation; II) rupture of C=C and C–N bonds after ring reduction; III) initial ring hydroxylation. The study not only provides a novel strain for the high-efficient degradation of 3-MP, but also contributes to an in-depth understanding of 3-MP biotransformation.

Achieving Near-Infrared Phosphorescence Supramolecular Hydrogel Based on Amphiphilic Bromonaphthalimide Pyridinium Hierarchical Assembly.

Phosphorescent supramolecular hydrogels are currently a prevalent topic for their great promise in various photonic applications. Herein, an efficient near-infrared (NIR) phosphorescence supramolecular hydrogel is reported via the hierarchical assembly strategy in aqueous solution, which is fabricated from amphiphilic bromonaphthalimide pyridinium derivative (G), exfoliated Laponite (LP) nanosheets, and polymeric polyacrylamide (PAAm). Initially, G spontaneously self-aggregates into spherical nanoparticles covered with positively charged pyridinium units and emits single fluorescence at 410nm. Driven by electrostatic interactions with negatively charged nanosheets, the nanoparticles subsequently function as the cross-linked binders and coassemble with LP into supramolecular hydrogels with an engendered red room-temperature phosphorescence (RTP) up to 620nm. Benefiting from hydrogen-bonding interactions-mediated physical cross-linkage, the further introduction of PAAm not only significantly elevates the mechanical strength of the hydrogels showing fast self-healing capability, but also increases phosphorescence lifetime from 2.49to 4.20ms, especially generating phosphorescence at even higher temperature (τ 363 K = 2.46ms). Additionally, efficient RTP energy transfer occurs after doping a small amount of organic dye heptamethine cyanine (IR780) as an acceptor into hydrogels, resulting in a long-lived NIR emission at 823nm with a high donor/acceptor ratio, which is successfully applied for cell labeling in the NIR window.

Six-Cyclic Crown Ether-Type Pillar[5]Arene: Enhanced Binding Ability to Bispyridinium Derivatives.

A six-cyclic crown ether-type pillar[5]arene was synthesized, and the five ethylene oxide loops were located outside the cavity and not affected by temperature changes which was confirmed by variable-temperature NMR experiment in DMSO-d6 and CDCl3 and 2D 1H-1H NOESY experiment in CDCl3. The six-cyclic pillar[5]-crown also showed greater binding ability of host-guest with bis(pyridinium) derivatives than conventional alkoxy pillar[5]arenes that illustrated through 1H NMR titration spectroscopic experiment in acetone-d6/CDCl3 (1 : 1) and UV-vis titration experiments in CHCl3 at room temperature. The five benzocrown ethers at the periphery were able to bind metal cations by 1H NMR titration spectroscopic experiment in CD2Cl2/methanol-d4(9 : 1).

Discovery of Pyrazolo[1,5-a]pyridine Derivatives as Potent and Selective PI3Kγ/δ Inhibitors.

PI3Kγ and PI3Kδ plays critical roles in exerting immunosuppression by targeting regulatory T cells and myeloid cells. Dual inhibition of PI3Kγ and PI3Kδ has emerged as a novel therapeutic strategy for cancer immunotherapy. We herein report a series of pyrazolopyridine derivatives with distinct scaffolds as potent and selective dual inhibitors of PI3Kγ and PI3Kδ. Among them, 20e (IHMT-PI3K-315) displays an IC50 value of 4.0 and 9.1 nM against PI3Kγ and PI3Kδ respectively in biochemical assays. Meanwhile, it potently inhibits PI3Kγ and PI3Kδ-mediated phosphorylation of AKT S473 with EC50 values of 0.028 and 0.013 μM in cellular assays. In addition, 20e exhibits a favorable selectivity profile in protein kinases at 1 μM. In bone marrow-derived macrophages (BMDM), 20e can repolarize the M2 phenotype to the M1 phenotype. In vivo, 20e demonstrates acceptable pharmacokinetic properties and suppresses tumor growth in a MC38 syngeneic mouse model.

α-C(sp3)-H (Hetero)Arylation of Thioethers Enabled by Photoexcited Triplet Ketone Catalysis.

We report herein α-C(sp3)-H (hetero)arylation of thioethers enabled by dual nickel and photoexcited triplet ketone catalysis. The mild reaction conditions of this protocol tolerate a variety of functional groups and further facilitate the late-stage functionalization of biologically relevant molecules to afford corresponding products in moderate to good yields. Preliminary mechanistic studies suggest that the generation of the α-thioalkyl radical takes place through a hydrogen atom transfer (HAT) event, which is involved in the rate-limiting step and in the nickel cycle, the reaction of the α-thioalkyl radical with Ni(0)Ln catalyst followed by oxidative addition of aryl bromide is the dominating pathway. Furthermore, the heteroaromatic benzylic thioethers can also be achieved from the corresponding reduced 4-cyano pyridine derivatives in the presence of a ketone catalyst through a radical-radical coupling reaction without metal. The increased yield of the products in the presence of DABCO might indicate a higher rate of α-thioalkyl radical formation from thioethers through the HAT event by DABCO radical cation.

Iodine Mediated Annulation of Triethylamine, Aldehydes and 2‐Aminopyridines for the Synthesis of 3‐Formyl‐Imidazo [1,2‐a]pyridine Derivatives

AbstractWith triethylamine as a synthon, an alternative method for the synthesis of 3‐formyl imidazo[1,2‐a]pyridines has been accomplished from aldehydes, and 2‐aminopyridines. The reaction proceeded via iodine‐catalyzed C−N bond cleavage of triethylamine, generation of α,β‐unsaturated aldehyde in situ, and oxidative cyclization with air as the oxygen source. This protocol may facilitate the synthesis of imidazo[1,2‐a]pyridine derivatives and provide a reference for the usage of triethylamine as a synthon.

One-pot synthesis of 1, 2-dihydro [1,2,4] triazinium salt by copperassisted unprecedented cyclization reaction: Application in protein binding.

Copper catalyzed intramolecular annulation of 2-((2benzylidene-1-phenylhydrazineyl)methyl)pyridine derivatives was described. It was found that Cu(II) is reduced under the reaction condition to Cu(I). Synthesized 1, 2-dihydro [1,2,4] triazinium salt showed fluorescence activity in solid state. On treating with base, an instant increase in fluorescence was observed. A detailed physicochemical assessment underscored the robust DNA-binding prowess of the [1,2,4] triazinium cationic species (C1-C3) via intercalative mechanisms. Notably, binding assays with BSA accentuated the heightened nucleic acid affinity of these cationic species.

Enhancing Bioactivity of N,N,N-Chelating Rhodium(III) Complexes with Ionic Liquids: Toward Targeted Cancer Therapy.

This study investigates the potential of using ionic liquids as cosolvents to enhance the solubility and activity of poorly soluble rhodium(III) complexes, particularly those with diene, pyridine derivatives, and camphor-derived bis-pyrazolylpyridine ligands, in relation to 5'-GMP, CT-DNA, and HSA as well as their biological activity. Findings indicate that ionic liquids significantly increase the substitution activity of these complexes toward 5'-GMP while only marginally affecting DNA/HSA binding affinities with molecular docking, further confirming the experimental results. Lipophilicity assessments indicated good lipophilicity. Notably, cytotoxicity studies show that Rh2 is selectively effective against HeLa cancer cells, with IL1 and IL10 modulating the cytotoxic effects. Redox evaluations indicate that rhodium complexes induce oxidative stress in cancerous cells while maintaining redox balance in noncancerous cells. By elucidating the role of ionic liquids in modulating these effects, the study proposes a promising avenue for augmenting the efficacy and selectivity of cancer treatments, thus opening new horizons in cancer therapeutics.

Synthesis, structure and Hirshfeld surface analysis of pyridinium derivative crystals

Slow evaporation methods were employed to grow single crystals of 3-acetylpyridinium picrate (I), 4-acetylpyridinium picrate (II), and pyridin-4-ylmethanaminium 2,2-diphenylacetate hydrate (III). Crystal (I) and (III) crystallize triclinic crystal system with a centric (Pī) space group and (II) crystallize in a monoclinic system with a centric (P21/c) space group. Various types of non-covalent interactions take part successfully in the construction of 3D networks in the compounds. Optical reflectance measurements showed 2.57, 2.66, and 4.45 eV as band gaps for (I), (II) and (III) respectively. TG/DTA analysis reveals the thermal pattern of the compounds. Intermolecular interactions are quantified by Hirshfeld surface analysis.

Edaravone N-benzyl pyridinium derivatives: BACE-1 inhibition, kinetics and in silico binding pose determination

BACE-1 plays a pivotal role in the production of β-amyloid (Aβ) peptides, implicated in Alzheimer's Disease (AD) pathology. We previously described edaravone N-benzyl pyridinium derivatives (EBPDs) that exhibited multifunctional activity against multiple AD targets. In this study we explored the EBPDs BACE-1 inhibitory activity to potentially enhance the compounds therapeutic profile. The EBPDs exhibited moderate BACE-1 inhibitory activity (IC50 = 44.10 µM - 123.70 µM) and obtained IC50 values between 2.0 and 5.8-fold greater than resveratrol, a known BACE-1 inhibitor (IC50 = 253.20 µM), in this assay. Compound 3 was the most potent inhibitor with an IC50 of 44.10 µM and a Ki of 19.96 µM and a mixed-type mode of inhibition that favored binding in a competitive manner. Molecular docking identified crucial interactions with BACE-1 active site residues, supported by 100 ns MD simulations. The study highlighted the EBPDs therapeutic potential as BACE-1 inhibitors and multifunctional anti-AD therapeutic agents.

Leveraging the properties of pyridine derivatives using DFT analysis to achieve breakthroughs in supercapacitance advancements

Leveraging the properties of pyridine derivatives using DFT analysis to achieve breakthroughs in supercapacitance advancements

A Review of Recent Progress on the Anticancer Activity of Heterocyclic Compounds

AbstractCancer is one of the most daunting illnesses in the world as compared to many other human diseases. This review article aims to summarize the literature that is already published based on heterocyclic anticancer compounds. Under this broad topic we try to shed a light on anticancer potentiality of oxygen-, sulfur-, and nitrogen-containing heterocyclic compounds, such as quinolines, pyrroles, pyrimidines, pyridines, indoles, also sulfonamides linked heterocycles, benzimidazoles and oxadiazoles.1 Introduction1.1 Drugs in Use for Cancer Treatment1.2 Recently Discovered Anticancer Drugs2 Various Classes of Compounds as Anticancer Agents2.1 Quinoline Derivatives as Anticancer Agents2.2 Benzimidazoles as Anticancer Agents2.3 Indole: A Privileged Scaffold for the Design of Anticancer Agents2.4 Pyrimidine Derivatives as Anticancer Agents2.5 Pyridine Derivatives as Anticancer Agents2.6 Pyrrole Derivatives as Anticancer Agents2.7 Sulfonamides linked with heterocycles as Anticancer Agents2.8 Oxadiazole and Its Derivatives as Anticancer Compounds2.9 Benzothiazole-Triazole Hybrids as Anticancer Compounds3 Conclusion

Nanostructured Iron (III)-Copper (II) Binary Oxide as a Highly Efficient Magnetically Recoverable Nanocatalyst for Facile One-pot Synthesis of 2, 4, 5-trisubstituted Imidazole and 1, 4-dihydro Pyridine Derivatives under Solvent-free Conditions

Abstract: The Fe (III)-Cu (II) binary oxide magnetic nanocatalyst emerges as an environmentally friendly and highly efficient solid acid catalyst, demonstrating remarkable utility in the one-pot synthesis of 2, 4, 5-trisubstituted imidazole and 1,4-dihydropyridine compounds, all achieved under solvent-free conditions. A facile co-precipitation method was used to synthesize nanostructured Fe-Cu binary oxide. Notably, this Fe-Cu binary oxide magnetic nanocatalyst proves its eco-friendly credentials as an exceptionally efficient and reusable catalyst, offering ease of handling, recovery, and multiple uses with minimal reactivity loss. Furthermore, the Fe (III)-Cu (II) binary oxide magnetic nanocatalyst's magnetic separability enhances its practicality, allowing for effortless catalyst retrieval after reactions. Significantly, the structural characteristics are meticulously elucidated through advanced analytical techniques, including 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. This work presents a versatile and sustainable solution for catalysis, with wide-reaching implications for green chemistry and the development of reusable, efficient catalysts for organic synthesis. The exceptional performance and eco-friendliness of the Fe-Cu binary oxide magnetic nanocatalyst underscore its practical significance. Fe-Cu binary oxide magnetic nanocatalyst exhibits the highest catalytic activity compared to others. The employment of this catalyst consistently delivers excellent yields in the target reactions, highlighting its potential to contribute positively to sustainable chemical processes.

Synthesis of (bi)pyridine derivatives of ornidazole

Synthesis of (bi)pyridine derivatives of ornidazole

Synthesis and computational studies of new pyridine, pyrazole, pyran, and pyranopyrimidine-based derivatives of potential antimicrobial activity as DNA gyrase and topoisomerase IV inhibitors

In this study, new derivatives based on pyridine, pyrazole, pyran, and pyranopyrimidine scaffolds 5–14 were designed and synthesized. The newly synthesized compounds were characterized using microanalytical and spectral data. Using amoxicillin and amphotericin B, two common antibacterial and antifungal medications, respectively, the antimicrobial activity of the new compounds was assessed against a variety of strains of both Gram-positive and Gram-negative bacteria as well as fungal infections. The most promising activity was achieved by pyridine-based derivatives 5, 7a, and 7b, which exhibited MIC values ranging from 0.95 to 18.04 µM against the examined bacterial strains and ranging from 4.65 to 33.16 µM against the examined fungal strains. The later derivatives were also evaluated as E. coli DNA gyrase B/topoisomerase IV inhibitors in comparison with novobiocin as a standard drug. Although the assessed candidates 5, 7a, and 7b exhibited a promising suppression impact against E. coli DNA gyrase B (IC50 = 3.11 ± 0.14, 3.85 ± 0.20, and 4.05 ± 0.10, respectively, IC50 novobiocin= 3.64 ± 0.10 µM), they showed detectable less suppression impact against Topoisomerase IV than that of the reference drug with IC50 values of 19.72 ± 1.00, 79.33 ± 0.25, 85.14 ± 0.10, and 13.42 ± 0.05 µM, respectively. Additionally, the safety profiles of 5, 7a, and 7b against WI38 cells were significantly superior to that of novobiocin (IC50 = 138 ± 0.33, 170 ± 0.40, 163.3 ± 0.17, and 86.2 ± 0.03 µM, respectively).Lastly, molecular docking was used to examine the most active derivatives 5, 7a, and 7b's binding capacity to the target DNA gyrase B/topoisomerase IV. The molecules exhibited various H-interactions with the amino acid residues Asp73, Arg76, and Val71 in E. coli DNA gyrase, where compound 5 exhibited H-bonding with the Asp1069 side chain of E. coli Topoisomerase IV. Additional in silico ADMET studies were conducted to represent their oral bioavailability and drug-likeness characteristics.

Design, Synthesis and Activity Against Drug‐Resistant Bacteria Evaluation of 1H‐Pyrazole‐[3,4‐b] Pyridine Derivatives

AbstractThe urgent need for novel antibiotics with potent activity against drug‐resistant bacteria is paramount in light of the escalating problem of antibiotic resistance. In this study, we evaluate the antibacterial efficacy of a series of newly designed and synthesized 1H pyrazole‐[3,4‐b]pyridine derivatives against various Gram‐positive and Gram‐negative bacterial strains. Among these derivatives, compound 15 q exhibits comparable antibacterial activity to the established medication Linezolid, demonstrating a minimum inhibitory concentration (MIC) value of 2 μg/mL against both the clinically resistant strain S. aureus M20 and the Gram‐positive bacterium S. aureus ATCC25923. Molecular docking analysis reveals that compound 15 q can interact with nucleotide residue G2505, providing initial insights into its underlying molecular mechanism responsible for its antibacterial activity. Therefore, compound 15 q holds great promise as a lead compound for potential therapeutic interventions against bacterial infections.