The Expanding Role of Pyridine and Dihydropyridine Scaffolds in Drug Design

Late-Stage Saturation of Drug Molecules

The available methods of chemical synthesis have arguably contributed to the prevalence of aromatic rings, such as benzene, toluene, xylene, or pyridine, in modern pharmaceuticals. Many such sp2-carbon-rich fragments are now easy to synthesize using high-quality cross-coupling reactions that click together an ever-expanding menu of commercially available building blocks, but the products are flat and lipophilic, decreasing their odds of becoming marketed drugs. Converting flat aromatic molecules into saturated analogues with a higher fraction of sp3 carbons could improve their medicinal properties and facilitate the invention of safe, efficacious, metabolically stable, and soluble medicines. In this study, we show that aromatic and heteroaromatic drugs can be readily saturated under exceptionally mild rhodium-catalyzed hydrogenation, acid-mediated reduction, or photocatalyzed-hydrogenation conditions, converting sp2 carbon atoms into sp3 carbon atoms and leading to saturated molecules with improved medicinal properties. These methods are productive in diverse pockets of chemical space, producing complex saturated pharmaceuticals bearing a variety of functional groups and three-dimensional architectures. The rhodium-catalyzed method tolerates traces of dimethyl sulfoxide (DMSO) or water, meaning that pharmaceutical compound collections, which are typically stored in wet DMSO, can finally be reformatted for use as substrates for chemical synthesis. This latter application is demonstrated through the late-stage saturation (LSS) of 768 complex and densely functionalized small-molecule drugs.

Design, synthesis, biological and computational screening of novel pyridine-based thiadiazole derivatives as prospective anti-inflammatory agents

In this study, a novel series of pyridine-based thiadiazole derivatives (NTD1-NTD5) were synthesized as prospective anti-inflammatory agents by combining substituted carboxylic acid derivatives of 5-substituted-2-amino-1,3,4-thiadiazole with nicotinoyl isothiocyanate in the presence of acetone. The newly synthesized compounds were characterized by FTIR, 1H NMR, 13C NMR, and mass spectrometry. First, the compounds underwent rigorous in vivo testing for acute toxicity and anti-inflammatory activity and the results revealed that three compounds-NTD1, NTD2, and NTD3, displayed no acute toxicity and significant anti-inflammatory activity, surpassing the efficacy of the standard drug, diclofenac. Notably, NTD3, which featured benzoic acid substitution, emerged as the most potent anti-inflammatory agent among the screened compounds. To further validate these findings, an in silico docking study was carried out against COX-2 bound to diclofenac (PDB ID: 1pxx). The computational analysis demonstrated that NTD2, and NTD3, exhibited substantial binding affinity, with the lowest binding energies (-8.5 and -8.4, kcal/mol) compared to diclofenac (-8.4 kcal/mol). This alignment between in vivo and in silico data supported the robust anti-inflammatory potential of these derivatives. Moreover, molecular dynamics simulations were conducted, extending over 100 ns, to examine the dynamic interactions between the ligands and the target protein. The results solidified NTD3's position as a leading candidate, showing potent inhibitory activity through strong and sustained interactions, including stable hydrogen bond formations. This was further confirmed by RMSD values of 2-2.5 Å and 2-3Ǻ, reinforcing NTD3's potential as a useful anti-inflammatory agent. The drug likeness analysis of NTD3 through SwissADME indicated that most of the predicted parameters including Lipinski rule were within acceptable limits. While these findings are promising, further research is necessary to elucidate the precise relationships between the chemical structures and their activity, as well as to understand the mechanisms underlying their pharmacological effects. This study lays the foundation for the development of novel anti-inflammatory therapeutics, potentially offering improved efficacy and safety profiles.

Metal-Free Visible-Light Catalytic Deoxygenation of Azaaryl N-Oxides: Harnessing Photons for Efficient Greener Synthesis

Regio- and chemo-selective functionalization of electron deficient azaarenes often required their transformations to corresponding N-oxides and subsequent removal of oxygen after functionalization to get back the desired substituted azaarenes. An efficient metal-free visible-light photo-redox catalytic deoxygenation of N-oxides of azaheterocyclic compounds has been developed using acridinium based organo-photocatalyst in blue LED light. High efficiency and mildness of this methodology has been demonstrated through higher deoxygenation yield of wide variety of azaheterocyclic N-oxides with reactive functional groups. Robustness of the photocatalytic reduction has been demonstrated through easy scaling-up of the reaction to gram level without much change in the reaction yield.

Design, Synthesis, and Biological Evaluation of Ferulic Acid Template-Based Novel Multifunctional Ligands Targeting NLRP3 Inflammasome for the Management of Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia, which arises due to low levels of acetyl and butyrylcholines, an increase in oxidative stress, inflammation, metal dyshomeostasis, Aβ and tau aggregations. The currently available drugs for AD treatment can provide only symptomatic relief without interfering with pathological hallmarks of the disease. In our ongoing efforts to develop naturally inspired novel multifunctional molecules for AD, systematic SAR studies on EJMC-4e were caried out to improve its multifunctional properties. The rigorous medicinal efforts led to the development of 12o, which displayed a 15-fold enhancement in antioxidant properties and a 2-fold increase in the activity against AChE and BChE over EJMC-4e. Molecular docking and dynamics studies revealed the binding sites and stability of the complex of 12o with AChE and BChE. The PAMPA-BBB assay clearly demonstrated that 12o can easily cross the blood-brain barrier. Interestingly, 12o also expresses promising metal chelation activity, while EJMC-4e was found to be devoid of this property. Further, 12o inhibited metal-induced or self Aβ1-42 aggregation. Observing the neuroprotection ability of 12o against H2O2-induced oxidative stress in the PC-12 cell line is noteworthy. Furthermore, 12o also inhibited NLRP3 inflammasome activation and attenuated mitochondrial-induced ROS and MMP damage caused by LPS and ATP in HMC-3 cells. In addition, 12o is able to effectively reduce mitochondrial and cellular oxidative stress in the AD Drosophila model. Finally, 12o could reverse memory impairment in the scopolamine-induced AD mice model, as evident through in vivo and ex vivo studies. These findings suggest that this compound may act as a promising candidate for further improvement in the management of AD.

Activity prediction, structure-based drug design, molecular docking, and pharmacokinetic studies of 1,4-dihydropyridines derivatives as α-amylase inhibitors

Objectives

Diabetes places a substantial economic burden on countries worldwide. The costs associated with diabetes management, including healthcare services, medications, monitoring equipment, and productivity losses, are substantial. The International Diabetes Federation has estimated that global healthcare expenditures associated with diabetes and its complications exceed hundreds of billions of dollars annually. Therefore, a critical need exists to develop drugs that are highly effective, affordable, and easily accessible to society.

Methods

This study explored the structural modification of 1,4-DHP derivatives to identify specific α-amylase inhibitors, with the aim of developing more effective and accessible drugs for diabetes. We evaluated the activity and binding ability of the designed compounds. In addition, we performed drug-likeness and pharmacokinetic studies on the modified compounds.

Results

Equation (1) had the highest accuracy, on the basis of internal and external assessment parameters, including R2int = 0.852, R2adj = 0.803, Q2cv = 0.731, and R2ext = 0.884. Moreover, the five potent analogs identified through structure-based drug design demonstrated a more favorable interaction than observed for the template or acarbose. Additionally, comprehensive studies on the drug-like properties and pharmacokinetics of the designed compounds supported their oral safety and favorable pharmacokinetic profiles.

Conclusions

The designed analogs show promise for developing new hypoglycemic agents. Their positive attributes and performance suggest that they may potentially serve as candidates for further research in improving treatments for high blood sugar-associated conditions.

Design, Synthesis and In-Silico Studies of Piperidine-Dihydropyridine Hybrids as Anticancer Agents

In this study, we designed, synthesized and characterized a novel series of piperidine-dihydropyridine hybrid compounds and characterized them by 1H-NMR, 13C NMR, mass spectrometry (MS), and elemental analysis. Subsequently, we assessed their in vitro anticancer potentials against the human breast adenocarcinoma cell line MCF-7 and the lung cancer cell line A-549. Several of these compounds demonstrated significant activity, with IC50 values ranging from 15.94 μM to 48.04 μM for A-549 and 24.68 μM to 59.12 μM for MCF-7, when compared to the reference drug Cisplatin.Notably, a compound featuring a 3-fluoro substitution in the carboxamide series exhibited robust inhibitory effects, with an IC50 of 15.94±0.201 μM against A-549 cells and an IC50 of 22.12±0.213 μM against MCF-7 cells, respectively. Additionally, a compound containing a cyclobutyl ring displayed potent activity, with an IC50 of 16.56±0.125 μM against A-549 and an IC50 of 24.68±0.217 μM against MCF-7 cells, respectively. Furthermore, molecular docking studies against the Epidermal Growth Factor Receptor (EGFR) (PDB ID: 2J6M) revealed favourable binding scores and interactions, suggesting their potential as promising candidates for further investigation in the context of anticancer drug development.

Photoinduced Radical Desulfurative C(sp3)-C(sp2) Coupling via Electron Donor-Acceptor Complexes

Herein, we disclose a radical desulfurative C-C coupling protocol for the synthesis of 4-alkylpyridines. A variety of substituents on both benzyl thiols and 4-cyanopyridines are tolerated. The reaction is carried out under mild and photocatalyst- and transition-metal-free conditions. Preliminary mechanistic studies show that an electron donor-acceptor complex is formed between benzyl thiols and 4-cyanopyridines under alkaline conditions. Then, a variety of 1°, 2°, and 3° C(sp3)-centered radicals was formed by cleavage of the C-S bond, and the 4-alkylpyridines were achieved through a radical-radical coupling with the pyridyl radical anion.

Regiodivergent Arylation of Pyridines via Zincke Intermediates

An arylation protocol for pyridines is described, via the ring-opened Zincke intermediate. Treatment of pyridines with triflic anhydride and a secondary amine produces an azahexatriene species, which undergoes regioselective Pd-catalyzed arylation at the putative C4 position. Recyclization then provides the pyridine products. Alternatively, metal-free arylation with a diaryliodonium salt is selective for the pyridine meta-position, affording a regiodivergent approach to pyridine biaryls from a common intermediate.

First total synthesis of caerulomycin K: a case study on selective, multiple C-H functionalizations of pyridines

Caerulomycins, natural alkaloids with antimicrobial properties, have been previously synthesized starting with highly pre-functionalized building blocks or requiring many functional group manipulations. In this work, we report the first total synthesis of caerulomycin K, a diversely trifunctionalized pyridine readily assembled in three steps exploiting the recent advancements in the C-H activation of N-heterocycles.

Dearomatization of Pyridines: Photochemical Skeletal Enlargement for the Synthesis of 1,2-Diazepines

In this report, we developed a unified and standardized one-pot sequence that converts pyridine derivatives into 1,2-diazepines by inserting a nitrogen atom. This skeletal transformation capitalizes on the in situ generation of 1-aminopyridinium ylides, which rearrange under UV light irradiation. A thorough evaluation of the key parameters (wavelength, reaction conditions, activating agent) allowed us to elaborate on a simple, mild, and user-friendly protocol. The model reaction was extrapolated to more than 40 examples, including drug derivatives, affording unique 7-membered structures. Mechanistic evidence supports the transient presence of a diazanorcaradiene species. Finally, pertinent transformations of the products, including ring contraction reactions to form pyrazoles, were conducted and paved the way to a broad application of the developed protocol.

Synthesis and Evaluation of Novel Substituted N-Aryl 1,4-Dihydropyridines as Antituberculostatic Agents

BACKGROUND

Tuberculosis has been the main cause of mortality of infectious diseases worldwide, with strongly limited therapeutic options. With increasing resistance and missing suitable drugs in those cases, there is a strong need for novel antituberculostatic drugs. We developed novel N-aryl 1,4-dihydropyridines with various substitution patterns to evaluate them as antituberculostatic agents.

METHODS

1,4-Dihydropyridine derivatives were synthesized and purified by column chromatography or recrystallization. The mycobacterial growth inhibition was determined in a fluorescent mycobacterial growth assay.

RESULTS

The compounds were prepared in a simple one-pot reaction under acidic conditions with structurally varied components. The substituent effects on the determined mycobacterial growth inhibitory properties are discussed.

CONCLUSION

Lipophilic diester substituted derivatives show promising activities that were additionally affected by the aromatic substituent functions. Thus, we identified compounds with activities almost reaching that of the used antimycobacterial drug as control.

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.

Overview of the New Bioactive Heterocycles as Targeting Topoisomerase Inhibitors Useful Against Colon Cancer

Colorectal cancer (CRC) is the third most common cancer globally, with high mortality. Metastatic CRC is incurable in most cases, and multiple drug therapy can increase patients' life expectancy by 2 to 3 years. Efforts are being made to understand the relationship between topoisomerase enzymes and colorectal cancer. Some studies have shown that higher expression of these enzymes is correlated to a poor prognosis for this type of cancer. One of the primary drugs used in the treatment of CRC is Irinotecan, which can be used in monotherapy or, more commonly, in therapeutic schemes such as FOLFIRI (Fluorouracil, Leucovorin, and Irinotecan) and CAPIRI (Capecitabine and Irinotecan). Like Camptothecin, Irinotecan and other compounds have a mechanism of action based on the formation of a ternary complex with topoisomerase I and DNA providing damage to it, therefore leading to cell death. Thus, this review focused on the principal works published in the last ten years that demonstrate a correlation between the inhibition of different isoforms of topoisomerase and in vitro cytotoxic activity against CRC by natural products, semisynthetic and synthetic compounds of pyridine, quinoline, acridine, imidazoles, indoles, and metal complexes. The results revealed that natural compounds, semisynthetic and synthetic derivatives showed potential in vitro cytotoxicity against several colon cancer cell lines, and this activity was often accompanied by the ability to inhibit both isoforms of topoisomerase (I and II), highlighting that these enzymes can be promising targets for the development of new chemotherapy against CRC. Pyridine analogs were considered the most promising for this study, while the evaluation of the real potential of natural products was limited by the lack of information in their work. Moreover, the complexes, although promising, presented as the main limitation the lack of selectivity.

In silico prediction and in vitro assessment of novel heterocyclics with antimalarial activity

The development of new antimalarials is paramount to keep the goals on reduction of malaria cases in endemic regions. The search for quality hits has been challenging as many inhibitory molecules may not progress to the next development stage. The aim of this work was to screen an in-house library of heterocyclic compounds (HCUV) for antimalarial activity combining computational predictions and phenotypic techniques to find quality hits. The physicochemical determinants, pharmacokinetic properties (ADME), and drug-likeness of HCUV were evaluated in silico, and compounds were selected for structure-based virtual screening and in vitro analysis. Seven Plasmodium target proteins were selected from the DrugBank Database, and ligands and receptors were processed using UCSF Chimera and Open Babel before being subjected to docking using Autodock Vina and Autodock 4. Growth inhibition of P. falciparum (3D7) cultures was tested by SYBR Green assays, and toxicity was assessed using hemolytic activity tests and the Galleria mellonella in vivo model. From a total of 792 compounds, 341 with good ADME properties, drug-likeness, and no interference structures were subjected to in vitro analysis. Eight compounds showed IC50 ranging from 0.175 to 0.990 µM, and active compounds included pyridyl-diaminopyrimido-diazepines, pyridyl-N-acetyl- and pyridyl-N-phenyl-pyrazoline derivatives. The most potent compound (UV802, IC50 0.178 µM) showed no toxicophoric and was predicted to interact with P. falciparum 1-cysperoxidredoxin (PfPrx1). For the remaining 7 hits (IC50 < 1 μM), 3 showed in silico binding to PfPrx1, one was predicted to bind the haloacid dehalogenase-like hydrolase and plasmepsin II, and one interacted with the plasmodial heat shock protein 90.

Development of Self-Assembling bis-1,4-Dihydropyridines: Detailed Studies of Bromination of Four Methyl Groups and Bromine Nucleophilic Substitution

One of the most important steps in the synthesis of 1,4-dihydropyridine (1,4-DHP) amphiphiles is the bromination of methyl groups in positions 2 and 6 of the entire ring. However, up to now, only N-bromosuccinimide was mainly used for bromination 1,4-DHPs. In this work, the synthesis of bis-1,4-DHP derivatives with ethyl and dodecyl ester groups attached to 1,4-DHP ring at positions 3 and 5 was performed by Hantzsch synthesis. The experimental studies were carried out to find out the best conditions and the agent for the tetra bromination of bis-1,4-DHP methyl groups at positions 2 and 6. Four different brominating agents were screened. The use of pyridinium bromide-perbromide in ethyl acetate was found to be optimal for the bromination of methyl groups. The bromination reaction was followed by the synthesis of cationic pyridine moiety containing amphiphilic bis-1,4-DHP derivatives. By nucleophilic substitution of bromine with various substituted pyridines, 12 new amphiphilic bis-1,4-DHP derivatives were obtained. Evaluation of self-assembling properties of tetracationic bis-1,4-dihydropyridine derivatives by dynamic light scattering (DLS) measurements was also performed.

Vanadium(V) Pyridine-Containing Schiff Base Catecholate Complexes are Lipophilic, Redox-Active and Selectively Cytotoxic in Glioblastoma (T98G) Cells

Two new series of complexes with pyridine-containing Schiff bases, [VV O(SALIEP)L] and [VV O(Cl-SALIEP)L] (SALIEP=N-(salicylideneaminato)-2-(2-aminoethylpyridine; Cl-SALIEP=N-(5-chlorosalicylideneaminato)-2-(2-aminoethyl)pyridine, L=catecholato(2-) ligand) have been synthesized. Characterization by 1 H and 51 V NMR and UV-Vis spectroscopies confirmed that: 1) most complexes form two major geometric isomers in solution, and [VV O(SALIEP)(DTB)] (DTB=3,5-di-tert-butylcatecholato(2-)) forms two isomers that equilibrate in solution; and 2) tert-butyl substituents were necessary to stabilize the reduced VIV species (EPR spectroscopy and cyclic voltammetry). The pyridine moiety within the Schiff base ligands significantly changed their chemical properties with unsubstituted catecholate ligands compared with the parent HSHED (N-(salicylideneaminato)-N'-(2-hydroxyethyl)-1,2-ethanediamine) Schiff base complexes. Immediate reduction to VIV occurred for the unsubstituted-catecholato VV complexes on dissolution in DMSO. By contrast, the pyridine moiety within the Schiff base significantly improved the hydrolytic stability of [VV O(SALIEP)(DTB)] compared with [VV O(HSHED)(DTB)]. [VV O(SALIEP)(DTB)] had moderate stability in cell culture media. There was significant cellular uptake of the intact complex by T98G (human glioblastoma) cells and very good anti-proliferative activity (IC50 6.7±0.9 μM, 72 h), which was approximately five times higher than for the non-cancerous human cell line, HFF-1 (IC50 34±10 μM). This made [VV O(SALIEP)(DTB)] a potential drug candidate for the treatment of advanced gliomas by intracranial injection.

The latest perspectives of small molecules FMS kinase inhibitors

FMS kinase is a type III tyrosine kinase receptor that plays a central role in the pathophysiology and management of several diseases, including a range of cancer types, inflammatory disorders, neurodegenerative disorders, and bone disorders among others. In this review, the pathophysiological pathways of FMS kinase in different diseases and the recent developments of its monoclonal antibodies and inhibitors during the last five years are discussed. The biological and biochemical features of these inhibitors, including binding interactions, structure-activity relationships (SAR), selectivity, and potencies are discussed. The focus of this article is on the compounds that are promising leads and undergoing advanced clinical investigations, as well as on those that received FDA approval. In this article, we attempt to classify the reviewed FMS inhibitors according to their core chemical structure including pyridine, pyrrolopyridine, pyrazolopyridine, quinoline, and pyrimidine derivatives.

Podophyllotoxin: Recent Advances in the Development of Hybridization Strategies to Enhance Its Antitumoral Profile

Podophyllotoxin is a naturally occurring cyclolignan isolated from rhizomes of Podophyllum sp. In the clinic, it is used mainly as an antiviral; however, its antitumor activity is even more interesting. While podophyllotoxin possesses severe side effects that limit its development as an anticancer agent, nevertheless, it has become a good lead compound for the synthesis of derivatives with fewer side effects and better selectivity. Several examples, such as etoposide, highlight the potential of this natural product for chemomodulation in the search for new antitumor agents. This review focuses on the recent chemical modifications (2017-mid-2023) of the podophyllotoxin skeleton performed mainly at the C-ring (but also at the lactone D-ring and at the trimethoxyphenyl E-ring) together with their biological properties. Special emphasis is placed on hybrids or conjugates with other natural products (either primary or secondary metabolites) and other molecules (heterocycles, benzoheterocycles, synthetic drugs, and other moieties) that contribute to improved podophyllotoxin bioactivity. In fact, hybridization has been a good strategy to design podophyllotoxin derivatives with enhanced bioactivity. The way in which the two components are joined (directly or through spacers) was also considered for the organization of this review. This comprehensive perspective is presented with the aim of guiding the medicinal chemistry community in the design of new podophyllotoxin-based drugs with improved anticancer properties.

Urea-Promoted Neat Synthesis of Fused Dihydroisoquinolines and Disubstituted Pyridines: A Mechanistic Observation with Molecular-Sensing Studies

An efficient and short synthesis of fused dihydroisoquinolines, diaryl substituted pyridine derivatives in good to high yields has been established by using an environmentally safe, solvent-metal-oxidant-free tandem approach. In this article, we discuss how the electrocyclic reaction is more pronounced in the solid phase in the presence of urea, whereas the typical aza-Michael addition is more prominent in presence of arylamine in the solution phase for 3-(2-formylcycloalkenyl)acrylic ester derivative substrates. The wide range of substrates and urea-promoted neat synthesis made our approach more significant in medical and also analytical science. Moreover, an isoquinoline alkaloid decumbenine B analogue has been synthesized by using our newly developed neat methodology. We have also investigated the photophysical properties of the synthesized fused dihydroisoquinoline derivatives. One of the synthesized molecules was used as a sensor for the selective detection of toxic picric acid. Therefore, the effective neat synthesis and molecular sensing applications of these compounds made our approach more exciting in the field of heterocyclic chemistry.

Pyridine Derivatives as Insecticides─Part 4: Synthesis, Crystal Structure, and Insecticidal Activity of Some New Thienylpyridines, Thienylthieno[2,3-b]pyridines, and Related Heterocyclic Derivatives

The reaction of ethyl 5-cyano-2-methyl-4-(thiophen-2-yl)-6-thioxo-1,6-dihydropyridine-3-carboxylate (1) with 2-chloroacetamide or its N-aryl derivatives gave ethyl 6-((2-amino-2-oxoethyl)thio)-5-cyano-2-methyl-4-(thiophen-2-yl) nicotinate (2a) or its N-aryl derivatives 2b-f, respectively. Cyclization of 2a-f into their isomers 3a-f was carried out by heating in absolute ethanol in the presence of a catalytic amount of sodium ethoxide. The o-aminoamide 3a was reacted with some aryl aldehydes in refluxing ethanol containing a few drops of conc. HCl to afford the corresponding tetrahydropyrimidinones 4a-d. The cyclocondensation reaction of 3a with some cycloalkanones such as cyclopentanone and cyclohexanone gave the corresponding spiro compounds 5a,b. The crystal structures of compounds 2a and 2d were determined by single-crystal X-ray diffraction techniques. All new compounds were evaluated for their insecticidal activity toward nymphs and adults of Aphis gossypi.

AI molecular property prediction for Parkinson's Disease reveals potential repurposing drug candidates based on the increase of the expression of PINK1

BACKGROUND AND OBJECTIVE

Parkinson's Disease (PD), a common neurodegenerative disorder and one of the major current challenges in neuroscience and pharmacology, may potentially be tackled by the modern AI techniques employed in drug discovery based on molecular property prediction. The aim of our study was to explore the application of a machine learning setup for the identification of the best potential drug candidates among FDA approved drugs, based on their predicted PINK1 expression-enhancing activity.

METHODS

Our study relies on supervised machine learning paradigm exploiting in vitro data and utilizing the scaffold splits methodology in order to assess model's capability to extract molecular patterns and generalize from them to new, unseen molecular representations. Models' predictions are combined in a meta-ensemble setup for finding new pharmacotherapies based on the predicted expression of PINK1.

RESULTS

The proposed machine learning setup can be used for discovering new drugs for PD based on the predicted increase of expression of PINK1. Our study identified nitazoxanide as well as representatives of imidazolidines, trifluoromethylbenzenes, anilides, nitriles, stilbenes and steroid esters as the best potential drug candidates for PD with PINK1 expression-enhancing activity on or inside the cell's mitochondria.

CONCLUSIONS

The applied methodology allows to reveal new potential drug candidates against PD. Next to novel indications, it allows also to confirm the utility of already known antiparkinson drugs, in the new context of PINK1 expression, and indicates the potential for simultaneous utilization of different mechanisms of action.

NiH-Catalyzed Regio- and Enantioselective Hydroalkylation for the Synthesis of β- or γ-Branched Chiral Aromatic N-Heterocycles

A nickel hydride-catalyzed regio- and enantioselective hydroalkylation reaction was developed to give access to a library of chiral β- or γ-branched aromatic N-heterocycles. This intriguing asymmetric transformation features excellent selectivities, step- and atom-economies, and generating two kinds of chiral products through one synthetic strategy. Furthermore, the possible reaction mechanism was extensively investigated using numerous control experiments and density functional theory calculations.

A robust Zintl cluster for the catalytic reduction of pyridines, imines and nitriles

Despite p-block clusters being known for over a century, their application as catalysts to mediate organic transformations is underexplored. Here, the boron functionalized [P7] cluster [(BBN)P7]2- ([1]2-; BBN = 9-borabicyclo[3.3.1]nonane) is applied in the dearomatized reduction of pyridines, as well as the hydroboration of imines and nitriles. These transformations afford amine products, which are important precursors to pharmaceuticals, agrochemicals, and polymers. Catalyst [1]2- has high stability in these reductions: recycling nine times in quinoline hydroboration led to virtually no loss in catalyst performance. The catalyst can also be recycled between two different organic transformations, again with no loss in catalyst competency. The mechanism for pyridine reduction was probed experimentally using variable time normalization analysis, and computationally using density functional theory. This work demonstrates that Zintl clusters can mediate the reduction of nitrogen containing substrates in a transition metal-free manner.

Synthesis, characterization, antiproliferative activity, docking, and molecular dynamics simulation of new 1,3-dihydro-2H-benzimidazol-2-one derivatives

Cancer is a global public health problem that affects millions each year. Novel anticancer drug candidates are in need to treat various cancers and to overcome the resistance that exists against drugs in use. Benzimidazole derivatives have been reported as anticancer agents. These lead us to synthesize similar benzimidazole derivatives and investigate their anticancer activity. In this study, six new 1,3-dihydro-2H-benzimidazol-2-one-based molecules (2a-f) were synthesized. The structures of these molecules were verified by spectroscopic methods. The antiproliferative activities of molecules 2a-f were screened against a panel of human cancer cell lines, including the liver, colon, lung, and breast. The molecules were also tested towards normal human lung cell line to determine their selectivity. The results demonstrated that compound 2d had the highest cytotoxic effect compared to compounds 2a-c, 2e, and 2f against DLD-1 and MDA-MB-231 cell lines. The binding potential of the relatively active compound, 2d, with three targets was investigated through molecular docking. The stability of target-compound complexes procured from the docking was explored through molecular dynamics (MD) simulation. The docking and MD simulation studies revealed that compound 2d had the highest potential to bind to GALR3 among the targets. Furthermore, the computational pharmacokinetic study demonstrated that the synthesized compounds had drug-like properties.Communicated by Ramaswamy H. Sarma.

Simple dihydropyridine-based colorimetric chemosensors for heavy metal ion detection, biological evaluation, molecular docking, and ADMET profiling

In this study, two novel chemosensors containing dihydropyridine fragment namely; (2E, 2E')-1,1'-(2,6-dimethyl-1,4-dihydropyridine-3,5-diyl)bis(3-(4-(dimethylamino)phenyl)prop-2-en-1-one) (1), (2E,2E',4E,4E')-1,1' -(2,6-dimethyl-1,4-dihydropyridine-3,5-diyl)bis(5-(4-(dimethylamino)phenyl)penta-2,4-dien-1-one) (2) have been synthesized and characterized. The solvatochromic behavior was explored in different solvents of various polarities. The visual detection, as well as UV-Vis and fluorescence measurements were carried out to explore the colorimetric and optical sensing properties of the investigated chemosensors towards various metal ions such as Al3+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Mg2+, Hg2+ and Zn2+. The chemosensors 1 and 2 have strong detecting abilities, with excellent sensitivity and selectivity for Cu2+ and Fe3+, respectively, over the other metal ions. The chemosensors were totally reversible upon addition of EDTA to the formed complexes and displayed a turn on-off-on fluorescence response based on an effect of chelation-quenching fluorescence. The antioxidant activities of the investigated chemosensors were assessed. They were examined in-silico for their capacity to block the Akt signaling pathway, which is involved in cancer proliferation with interpreting their pharmacokinetics aspects. Furthermore, in-vitro antitumor evaluation against a panel of cancer cell lines for the investigated chemosensors has been examined. Conclusively, chemosensor 1 was more effective at scavenging free radicals and as an anticancer agent and could be exploited as a therapeutic candidate for cancer therapy than chemosensor 2 due to its potential inhibition of Akt protein.

Functionalized Pyridines: Synthesis and Toxicity Evaluation of Potential Insecticidal Agents against Aphis craccivora

Using ultrasound technology instead of traditional methods, some pyridine derivatives were prepared by a simple procedure via a four-component reaction of different aromatic aldehydes, acetyl aryl, sodium alkoxide, and malononitrile, and additionally, all prepared compounds were monitored for insecticidal activities toward nymphs and adults of cowpea aphid. Though a lot of insecticides are discovered as a novelty on the other hand, neonicotinoid compounds are reflected as the most affected insecticides against aphids and many other pests. Thus, some of the pyridine derivatives were chemically prepared as analogues to a large group of insecticides called neonicotinoids. Under laboratory conditions, the toxicity of these components was measured toward adults and nymphs of Aphis craccivora. With respect to the LC50 values, components 1f, 1d, and 1c have the utmost insecticidal bioactivity, with values of 0.080, 0.098, and 0.127 mg/L. This work covers the way to discover novel compounds for the prospective use as insecticidal representatives.

Robust Vanillin-Derived Poly(thioether imidazoles) as Both a Latent Curing and Toughening Agent for One-Component Epoxy Resins

One-component epoxy resins based on latent curing agents have garnered research attention owing to their outstanding storage stability and excellent processability, while their development considerably depends on the design and preparation of sustainable latent curing agents. Herein, taking structural advantage of lignin-derived vanillin, a biobased polymerizable aromatic imidazole monomer with α,ω-diene functionality was designed and prepared, which was applicable in subsequent thiol-ene polymerization, yielding a series of robust poly(thioether imidazoles) with excellent tunability of the structure and properties. The findings indicated that the precursors comprising poly(thioether imidazole) and commercially available epoxy resins could keep their fluidity at 25 °C for over 90 days and rapidly cured into resins under elevated temperature, demonstrating that the poly(thioether imidazole) can serve as both a latent curing and toughening agent for one-component epoxy resins because of homopolymerization initiated by imidazole groups and the introduction of an aliphatic chain in the as-prepared poly(thioether imidazole) matrix.

New NADPH Oxidase 2 Inhibitors Display Potent Activity against Oxidative Stress by Targeting p22phox-p47phox Interactions

NADPH oxidase (NOX2) is responsible for reactive oxygen species (ROS) production in neutrophils and has been recognized as a key mediator in inflammatory and cardiovascular pathologies. Nevertheless, there is a lack of specific NOX2 pharmacological inhibitors. In medicinal chemistry, heterocyclic compounds are essential scaffolds for drug design, and among them, indole is a very versatile pharmacophore. We tested the hypothesis that indole heteroaryl-acrylonitrile derivatives may serve as NOX2 inhibitors by evaluating the capacity of 19 of these molecules to inhibit NOX2-derived ROS production in human neutrophils (HL-60 cells). Of these compounds, C6 and C14 exhibited concentration-dependent inhibition of NOX2 (IC₅₀~1 µM). These molecules also reduced NOX2-derived oxidative stress in cardiomyocytes and prevented cardiac damage induced by ischemia-reperfusion. Compound C6 significantly reduced the membrane translocation of p47^phox, a cytosolic subunit that is required for NOX2 activation. Molecular docking analyses of the binding modes of these molecules with p47^phox indicated that C6 and C14 interact with specific residues in the inner part of the groove of p47^phox, the binding cavity for p22^phox. This combination of methods showed that novel indole heteroaryl acrylonitriles represent interesting lead compounds for developing specific and potent NOX2 inhibitors.

Late-Stage C-H Functionalization of Azines

Azines, such as pyridines, quinolines, pyrimidines, and pyridazines, are widespread components of pharmaceuticals. Their occurrence derives from a suite of physiochemical properties that match key criteria in drug design and is tunable by varying their substituents. Developments in synthetic chemistry, therefore, directly impact these efforts, and methods that can install various groups from azine C-H bonds are particularly valuable. Furthermore, there is a growing interest in late-stage functionalization (LSF) reactions that focus on advanced candidate compounds that are often complex structures with multiple heterocycles, functional groups, and reactive sites. Because of factors such as their electron-deficient nature and the effects of the Lewis basic N atom, azine C-H functionalization reactions are often distinct from their arene counterparts, and the application of these reactions in LSF contexts is difficult. However, there have been many significant advances in azine LSF reactions, and this review will describe this progress, much of which has occurred over the past decade. It is possible to categorize these reactions as radical addition processes, metal-catalyzed C-H activation reactions, and transformations occurring via dearomatized intermediates. Substantial variation in reaction design within each category indicates both the rich reactivity of these heterocycles and the creativity of the approaches involved.

Pyridine C(sp2)-H bond functionalization under transition-metal and rare earth metal catalysis

Pyridine is a crucial heterocyclic scaffold that is widely found in organic chemistry, medicines, natural products, and functional materials. In spite of the discovery of several methods for the synthesis of functionalized pyridines or their integration into an organic molecule, new methodologies for the direct functionalization of pyridine scaffolds have been developed during the past two decades. In addition, transition-metal-catalyzed C-H functionalization and rare earth metal-catalyzed reactions have flourished over the past two decades in the development of functionalized organic molecules of concern. In this review, we discuss recent achievements in the transition-metal and rare earth metal-catalyzed C-H bond functionalization of pyridine and look into the mechanisms involved.

Application of Zr-MOFs based copper complex in synthesis of pyrazolo[3, 4-b]pyridine-5-carbonitriles via anomeric-based oxidation

In this research article, Zr-MOFs based copper complex as a novel heterogeneous and porous catalyst was designed and prepared. The structure of catalyst has verified by various techniques such as FT-IR, XRD, SEM, N2 adsorption-desorption isotherms (BET), EDS, SEM-elemental mapping, TG and DTG analysis. UiO-66-NH2/TCT/2-amino-Py@Cu(OAc)2 was used as an efficient catalyst in the synthesis of pyrazolo[3,4-b]pyridine-5-carbonitrile derivatives. The aromatization of titled molecules is performed via a cooperative vinylogous anomeric-based oxidation both under air and inert atmospheres. The unique properties of the presented method are short reaction time, high yield, reusability of catalyst, synthesis of desired product under mild and green condition.

Synthesis of substituted pyridines with diverse functional groups via the remodeling of (Aza)indole/Benzofuran skeletons

Substituted pyridines with diverse functional groups are important structural motifs found in numerous bioactive molecules. Several methodologies for the introduction of various bio-relevant functional groups to pyridine have been reported, but there is still a need for a single robust method allowing the selective introduction of multiple functional groups. This study reports a ring cleavage methodology reaction for the synthesis of 2-alkyl/aryl 3-electron-withdrawing groups (esters, sulfones, and phosphonates) 5-aminoaryl/phenol pyridines via the remodeling of 3-formyl (aza)indoles/benzofurans. Totally ninety-three 5-aminoaryl pyridines and thirty-three 5-phenol pyridines were synthesized showing the robustness of the developed methodology. The application of this methodology further provided a privileged pyridine scaffold containing biologically relevant molecules and direct drug/natural product conjugation with ethyl 2-methyl nicotinate.

Advances on the biosynthesis of pyridine rings

Numerous studies have investigated the biosynthesis of pyridine heterocycles derived from nicotinic acid. However, metabolic pathways generating pyridine heterocycles in nature remain uninvestigated. Here, we summarize recent contributions conducted in the last decade on the biosynthetic pathways of non-derivate from nicotinic acid pyridine rings and discuss their implication on the study of natural products with pyridine structures.

Mapping new pharmacological interventions for cognitive function in Alzheimer's disease: a systematic review of randomized clinical trials

Background and Objective: Alzheimer's disease (AD) is a progressive neurodegenerative disorder, that is, characterized by cognitive decline. To date, there are no effective treatments for AD. Therefore, the objective of this study was to map new perspectives on the effects of pharmacological treatment on cognitive function and the overall psychological state in patients with AD. Methods: Two independent researchers searched for randomized clinical trials (RCTs) exploring new pharmacological approaches related to cognition in Alzheimer's disease in adults from 2018 to 2023 in PubMed, Web of Science, Scopus, and Cochrane Library databases. A total of 17 RCTs were included in this review. Results: The results show that in recent years, new drugs have been tested in patients with Alzheimer's disease, including masitinib, methylphenidate, levetiracetam, Jiannao Yizhi, and Huannao Yicong formulas. Most studies have been conducted in populations with mild to moderate Alzheimer's disease. Conclusion: Although some of the drugs found suggested improvement in cognitive function, the scarcity of available studies highlights the need for further research in this area. Systematic review registration: [www.crd.york.ac.uk/prospero], identifier [CRD42023409986].

Discovery of new pyridine heterocyclic hybrids; design, synthesis, dynamic simulations, and in vitro and in vivo breast cancer biological assays

Pyridine is a nitrogen bearing heterocyclic scaffold that shows a wide range of biological activities. The pyridine nucleus has become an interesting target for medicinal chemistry researchers worldwide. Several pyridine derivatives exhibited good anticancer effects against diverse cell lines. Therefore, to explore new anticancer pyridine entities, novel pyridine derivatives were designed and synthesized and evaluated for their anticancer abilities in vitro and in vivo. All of the target compounds were evaluated against three different human cancer cell lines (Huh-7, A549 and MCF-7) via MTT assay. Most of the compounds exhibited significant cytotoxic activities. Compounds 3a, 3b, 5a and 5b showed superior antiproliferative activities to Taxol. Where, compound 3b showed IC₅₀ values of 6.54, 15.54 and 6.13 μM compared to Taxol (6.68, 38.05, 12.32 μM) against Huh-7, A549 and MCF-7, respectively. Also, tubulin polymerization assay was carried out. The most potent compounds 3a, 3b, 5a and 5b could significantly inhibit tubulin polymerization with IC₅₀ values of 15.6, 4.03, 6.06 and 12.61 μM, respectively. Compound 3b exhibited the highest tubulin polymerization inhibitory effect with an IC₅₀ value of 4.03 μM compared to combretastatin (A-4) (1.64 μM). Molecular modeling studies of the designed compounds confirmed that most of the compounds made the essential binding interactions compared to the reference compound which assisted in the prediction of the structure requirements for the detected anticancer activity. Finally, in vivo studies showed that compound 3b could significantly inhibit breast cancer.

Recent Advances in Pyridine Scaffold: Focus on Chemistry, Synthesis, and Antibacterial Activities

Multidrug-resistant (MDR) pathogens have created a fatal problem for human health and antimicrobial treatment. Among the currently available antibiotics, many are inactive against MDR pathogens. In this context, heterocyclic compounds/drugs play a vital role. Thus, it is very much essential to explore new research to combat the issue. Of the available nitrogen-bearing heterocyclic compounds/drugs, pyridine derivatives are of special interest due to their solubility. Encouragingly, some of the newly synthesized pyridine compounds/drugs are found to inhibit multidrug-resistant S. aureus (MRSA). Pyridine scaffold bearing poor basicity generally improves water solubility in pharmaceutically potential molecules and has led to the discovery of numerous broad-spectrum therapeutic agents. Keeping these in mind, we have reviewed the chemistry, recent synthetic techniques, and bacterial preventative activity of pyridine derivatives since 2015. This will facilitate the development of pyridine-based novel antibiotic/drug design in the near future as a versatile scaffold with limited side effects for the next-generation therapeutics.

Multi-target antibacterial mechanism of ruthenium polypyridine complexes with anthraquinone groups against Staphylococcus aureus

Three new Ru(ii) complexes, [Ru(dtb)2PPAD](PF6)2 (Ru-1), [Ru(dmob)2PPAD](PF6)2 (Ru-2) and [Ru(bpy)2PPAD](PF6)2 (Ru-3) (dtb = 4,4'-di-tert-butyl-2,2'-bipyridine, dmob = 4,4'-dimethyl-2,2'-bipyridine, bpy = 2,2'-bipyridine and PPAD = 2-(pyridine-3-yl)-1H-imidazo[4,5f][1.10]phenanthracene-9,10-dione), were synthesized and characterized by 1H NMR and 13C NMR spectroscopy, HRMS and HPLC. Among them, Ru-1 showed excellent antimicrobial activity against Gram-positive bacteria Staphylococcus aureus (minimum inhibitory concentration (MIC) = 1 μg mL-1) and low hemolytic and cytotoxic activity. In addition, Ru-1 showed obviously rapid bactericidal activity, low resistance rate, bacterial biofilm destroying activity and high biosafety in vivo. Moreover, skin infection models and a mouse model of sepsis indicated that the anti-infective efficacy of Ru-1 was comparable to that of vancomycin. Mechanism exploration results showed that the antibacterial behavior is probably related with targeting of the bacterial cell membrane and inhibiting topoisomerase I.

Green Synthesis of Novel Pyridines via One-Pot Multicomponent Reaction and Their Anti-Inflammatory Evaluation

A functional and environmentally green procedure for the design of novel pyridine 5a-h and 7a-d derivatives through two pathways is presented. The first pathway is via a one-pot, four-component reaction of p-formylphenyl-4-toluenesulfonate (1), ethyl cyanoacetate (2), acetophenone derivatives 3a-h or acetyl derivatives 6a-d, and ammonium acetate (4) under microwave irradiation in ethanol. The advantages of this method are an excellent yield (82%-94%), pure products, a short reaction time (2-7 min), and low-cost processing. The second pathway was obtained by the traditional method with treatment of the same mixture under refluxing in ethanol, which afforded the same products, 5a-h and 7a-d, in less yield (71%-88%) and over a longer reaction time (6-9 h). The constructions of the novel compounds were articulated via spectral and elemental analysis. Overall, the compounds have been designed, synthesized, and studied for their in vitro anti-inflammatory activity using diclofenac as a reference drug (5 mg/kg). The most potent four compounds, 5a, 5f, 5g, and 5h, showed promising anti-inflammatory activity.

Asymmetric [5+1] Annulation via C-H Activation/1,4-Rh Migration/Double Bond Shift Using a Transformable Pyridazine Directing Group

N-Heterocycle-assisted C-H activation/annulation reactions have provided new concepts for the construction and transformation of azacycles. In this work, we disclose a [5+1] annulation reaction using a novel transformable pyridazine directing group (DG). The DG-transformable reaction mode led to the construction of a new heterocyclic ring accompanied by transformation of the original pyridazine directing group via a C-H activation/1,4-Rh migration/double bond shift pathway, affording the skeleton of pyridazino[6,1-b]quinazolines with a good substrate scope under mild conditions. Diverse fused cyclic compounds can be achieved by derivatization of the product. The asymmetric synthesis of the skeleton was also realized to afford the enantiomeric products with good stereoselectivity.

Enantioselective dearomatization reactions of heteroarenes by anion-binding organocatalysis

Catalytic asymmetric dearomatization of heteroaromatic compounds has received considerable attention in the last few years, since it allows for a fast expansion of the chemical space by converting relatively simple, flat molecules into complex, three dimensional structures with added value. Among different approaches, remarkable progress has been recently achieved by the development of organocatalytic dearomatization methods. In particular, the anion-binding catalysis technology has emerged as a potent alternative to metal catalysis, which together with the design of novel, tunable anion-receptor motifs, has provided new entries for the enantioselective dearomatization of heteroarenes through a chiral contact ion pair formation by activation of the electrophilic reaction partner. In this feature, we provide an overview of the different methodologies and advances in anion-binding catalyzed dearomatization reactions of different heteroarenes.

Ru(II)-Catalyzed One-Pot Synthesis of 1,2-Hydropyridines via a Three-Component Reaction

A ruthenium(II)-catalyzed one-pot synthesis of highly substituted 1,2-dihydropyridines (DHPs) via a three-component reaction system has been realized. The reaction is conducted using a simple Ru(II) catalyst without the addition of specific ligands. The catalytic system exhibits good functionality tolerance with a wide range of starting materials. The DHPs obtained can be easily converted into tetrahydropyridines and azabicyclo[4.2.0]octa-4,7-dienes by subsequent reduction or [2 + 2] cycloaddition reaction.

New Azacycles by One-Pot Three-Component Hantzsch-Like Synthesis of Tetra(hexa)azacyclopenta[a]anthracenes, Tetraazaindeno[5,4-b]fluorenes, and Oxatetraazacyclopenta[m]tetraphenes

New Azacycles by One-Pot Three-Component Hantzsch-Like Synthesis of Tetra(hexa)azacyclopenta[a]anthracenes, Tetraazaindeno[5,4-b]fluorenes, and Oxatetraazacyclopenta[m]tetraphenes (H. Butenschön, I. A. Abdelhamid et al.) #OpenAccess Multicomponent reactions (MCRs) are envisaged as an entry point for the synthesis of heterocyclic compounds with interesting biological activities. An efficient approach to annelated tetra(hexa)azacyclopenta[a]anthracenes, tetraazaindeno[5,4-b]fluorenes, and oxatetraazacyclopenta[m]tetraphene was accomplished using a three-component reaction involving 7-amino-2-methyl-3-phenylpyrazolo[1,5-a]pyrimidin-5-one with aromatic aldehydes and the corresponding active 1,3-dicarbonyl compounds (namely, dimedone, 1,3-dimethylbarbituric acid, 1,3-indanedione, and 4-hydroxycoumarine). The reactions were conducted in glacial acetic acid at reflux for 5 h to give the desired products in good yields (62-83 %). The chemical constitutions of all new products were confirmed spectroscopically.

Enzymatic synthesis of amlodipine amides and evaluation of their anti-Trypanosoma cruzi activity

Advancing with our project about the development of new antiparasitic agents, we have enzymatically synthesized a series of amides derived from amlodipine, a calcium channel blocker used as an antihypertensive drug. Through lipase-catalyzed acylation with different carboxylic acids, nineteen amlodipine derivatives were obtained, eighteen of which were new compounds. To optimize the reaction conditions, the influence of several reaction parameters was analyzed, finding different requisites for aliphatic carboxylic acids and phenylacetic acids. All synthesized compounds were evaluated as antiproliferative agents against Trypanosoma cruzi, the etiological agent of American trypanosomiasis (Chagas' disease). Some of them showed significant activity against the amastigote form of T. cruzi, the clinically relevant form of the parasite. Among synthesized compounds, the derivatives of myristic and linolenic acids showed higher efficacy and lower cytotoxicity. These results added to the advantages shown by the enzymatic methodology, such as mild reaction conditions and low environmental impact, making this approach a valuable way to synthesize these amlodipine derivatives with an application as promising antiparasitic agents.

Synthesis of Dihydropyrimidines: Isosteres of Nifedipine and Evaluation of Their Calcium Channel Blocking Efficiency

Hypertension and cardiovascular diseases related to it remain the leading medical challenges globally. Several drugs have been synthesized and commercialized to manage hypertension. Some of these drugs have a dihydropyrimidine skeleton structure, act as efficient calcium channel blockers, and affect the calcium ions' intake in vascular smooth muscle, hence managing hypertension. The synthesis of such moieties is crucial, and documenting their structure-activity relationship, their evolved and advanced synthetic procedures, and future opportunities in this area is currently a priority. Tremendous efforts have been made after the discovery of the Biginelli condensation reaction in the synthesis of dihydropyrimidines. From the specific selection of Biginelli adducts to the variation in the formed intermediates to achieve target compounds containing heterocylic rings, aldehydes, a variety of ketones, halogens, and many other desired functionalities, extensive studies have been carried out. Several substitutions at the C3, C4, and C5 positions of dihydropyrimidines have been explored, aiming to produce feasible derivatives with acceptable yields as well as antihypertensive activity. The current review aims to cover this requirement in detail.

Pyridine Derivatives as Potential Inhibitors for Coronavirus SARS-CoV-2: A Molecular Docking Study

Coronavirus SARS-CoV-2, a causative agent for the global epidemic disease COVID-19, which has a highest modality rate. Several initiatives have been undertaken to repurpose current antiviral medications and tested the classic pyridine derivatives (PyDev), which have showed substantial therapeutic potential against a variety of illnesses and also have several biological functions such as, antibacterial, antiviral, and anti-inflammatory. However, limited reports are available for the treatment of Coronavirus SARS-CoV-2 using PyDev. Hence, the possibilities of the best-described PyDev molecules of powerful Coronavirus SARS-CoV-2 inhibitors have been attempted in this investigation. This study primarily focused on blocking four key targets of Coronavirus SARS-CoV-2 proteins. Terpyridine has shown the greatest inhibitory potential (with a binding energy of −8.8 kcal/mol) against all four coronavirus targets. This study results would pave the potential lead medication for Coronavirus SARS-CoV-2 therapeutic strategies.