Design, one-pot green synthesis and antimicrobial evaluation of novel imidazopyridine bearing pyran bis-heterocycles

Heteroarylation of Sulfenamides for Modular Synthesis of Antimicrobial Sulfilimines via Sulfinimidoyl Fluoride Intermediates

We herein disclose a mild metal-free strategy for the construction of heteroaryl-derived sulfilimines. Central to this approach is the in situ generated sulfinimidoyl fluoride intermediate that exhibits an optimal balance of reactivity and stability for efficient S(IV)-derived SuFEx reactions with heteroarenes without Lewis acids or base additives. This protocol enables the rapid incorporation of a broad range of heteroarenes to afford diverse sulfilimine scaffolds with potent antimicrobial activities against plant pathogens.

Ligand-free palladium-catalyzed synthesis of 3-(2,2-dialkyl-2H-chromen-4-yl)-2-phenylimidazo[1,2-a]pyridine derivatives: molecular docking investigation of their potential as DNA gyrase inhibitors and evaluation of their antibacterial activities

Palladium-catalyzed reactions between imidazo[1,2-a]pyridine derivatives and 4-bromo-2,2-dialkyl-substituted 2H-chromenes under microwave irradiation at 100 W, 120 °C for 20-30 min provided a series of new 3-(2,2-dialkyl-2H-chromen-4-yl)-2-phenylimidazo[1,2-a]pyridine derivatives in good to excellent yields. The structures of the synthesized compounds were confirmed through spectroscopic techniques (NMR and HRMS). The X-ray single-crystal structure of compound 16e was also determined. Shorter reaction time, high yield and good substrate scope were the major advantages of this method. All these compounds were further investigated in vitro for the evaluation of their antibacterial potency using the agar well diffusion method against human pathogenic Gram-negative E. coli and Gram-positive S. aureus bacteria, with the determination of their minimum inhibitory concentration (MIC) values. Indeed, compound 16h strongly inhibited DNA gyrase in silico with a binding affinity of -8.7 kcal mol-1 and exhibited zone of inhibition (ZI) values of 19 mm and MIC values of 10 μg mL-1 in both Gram-negative E. coli and Gram-positive S. aureus, relative to the standard drug gentamicin. By analyzing the structure-activity relationships based on the molecular docking results and the potent antibacterial activities, it could be concluded that these new phenylimidazo[1,2-a]pyridine-chromene derivatives have the potential to be effective druggable antibacterial agents.

Identification of a New Promising BAG3 Modulator Featuring the Imidazopyridine Scaffold

The antiapoptotic BAG3 protein plays a crucial role in cellular proteostasis and it is involved in several signalling pathways governing cell proliferation and survival. Owing to its multimodular structure, it possesses an extensive interactome including the molecular chaperone HSP70 and other specific cellular partners, which make it an eminent factor in several pathologies, particularly in cancer. Despite its potential as a therapeutic target, very few BAG3 modulators have been disclosed so far. Here we describe the identification of a promising BAG3 modulator able to bind the BAG domain of the protein featuring an imidazopyridine scaffold and obtained through the application of the Groebke-Blackburn-Bienaymé chemical synthesis procedure. The disclosed compound 10 showed a relevant cytotoxic activity, and in line with the biological profile of BAG3 disruption, it induced the activation of caspase 3 and 9.

Bortoluzzi A, Sandjo LP, Braga AL, F. de Assis F. Highly Enantioselective Lewis Acid Catalyzed Conjugate Addition of Imidazo[1,2-a]pyridines to α,β-Unsaturated 2-Acylimidazoles under Mild Conditions

A highly enantioselective protocol for the conjugate addition of 2-arylimidazo[1,2-a]pyridines and other imidazo derivatives to α,β-unsaturated 2-acylimidazoles is described. The method uses a previously reported chiral-at-metal rhodium catalyst and provides the corresponding adducts in yields of 25-98% with enantioselectivities up to er > 99:1. Additionally, the transformation proceeds under mild conditions using ethanol as the solvent at room temperature.

Reaction Pattern and Mechanistic Aspects of Iodine and Iodine-Based Reagents in Selenylation of Aliphatic, Aromatic, and (Hetero)Cyclic Systems

Organoselenium compounds have been the subject of extensive research since the discovery of the biologically active compound ebselen. Ebselen has recently been found to show activity against the main protease of the virus responsible for COVID-19. Other organoselenium compounds are also well-known for their diverse biological activities, with such compounds exhibiting interesting physical properties relevant to the fields of electronics, materials, and polymer chemistry. In addition, the incorporation of selenium into various organic molecules has garnered significant attention due to the potential of selenium to enhance the biological activity of these molecules, particularly in conjunction with bioactive heterocycles. Iodine and iodine-based reagents play a prominent role in the synthesis of organoselenium compounds, being valued for their cost-effectiveness, non-toxicity, and ease of handling. These reagents efficiently selenylate a broad range of organic substrates, encompassing alkenes, alkynes, and cyclic, aromatic, and heterocyclic molecules. They serve as catalysts, additives, inducers, and oxidizing agents, facilitating the introduction of different functional groups at alternate positions in the molecules, thereby allowing for regioselective and stereoselective approaches. Specific iodine reagents and their combinations can be tailored to follow the desired reaction pathways. Here, we present a comprehensive review of the progress in the selenylation of organic molecules using iodine reagents over the past decade, with a focus on reaction patterns, solvent effects, heating, microwave, and ultrasonic conditions. Detailed discussions on mechanistic aspects, such as electrophilic, nucleophilic, radical, electrochemical, and ring expansion reactions via selenylation, multiselenylation, and difunctionalization, are included. The review also highlights the formation of various cyclic, heterocyclic, and heteroarenes resulting from the in situ generation of selenium intermediates, encompassing cyclic ketones, cyclic ethers, cyclic lactones, selenophenes, chromones, pyrazolines, pyrrolidines, piperidines, indolines, oxazolines, isooxazolines, lactones, dihydrofurans, and isoxazolidines. To enhance the reader's interest, the review is structured into different sections covering the selenylation of aliphatic sp2/sp carbon and cyclic sp2 carbon, and then is further subdivided into various heterocyclic molecules.

T5S1607 identified as a antibacterial FtsZ inhibitor：Virtual screening combined with bioactivity evaluation for the drug discovery

Due to antibiotic overuse, many bacteria have developed resistance, creating an urgent need for novel antimicrobial agents. It has been established that the filamentous temperature-sensitive mutant Z (FtsZ) of the bacterial cell division protein is an effective and promising antibacterial target. In this study, the optimal proteins were assessed by early recognition ability and the processed compound libraries were virtually screened using Vina. This effort resulted in the identification of 14 potentially active antimicrobial compounds. Among them, the compound T5S1607 demonstrated remarkable antibacterial efficacy against Bacillus subtilis ATCC9732 (MIC = 1 μg/mL) and Staphylococcus aureus ATC5C6538 (MIC = 4 μg/mL). Furthermore, in vitro experiments demonstrated that the selected compound T5S1607 rapidly killed bacteria and induced FtsZ protein aggregation, preventing bacterial division and leading to bacterial death. Additionally, cell toxicity and hemolysis experiments indicate that compound T5S1607 exhibits minimal toxicity to LO2 cells and shows no significant hemolytic effects on mammalian cells in vitro at the MIC concentration range. All the results indicate that compound T5S1607 is a promising antibacterial agent and a potential FtsZ inhibitor. In conclusion, this work successfully discovered FtsZ inhibitors with good activity through the virtual screening drug discovery process.

Imidazo[1,2-A]Pyridine: Potent Biological Activity, SAR and Docking Investigations (2017-2022)

BACKGROUND

Regarding scientific research, Imidazo[1,2-a] pyridine derivatives are constantly being developed due to the scaffold's intriguing chemical structure and varied biological activity. They are distinctive organic nitrogen-bridged heterocyclic compounds that have several uses in medicines, organometallics and natural products. It has become a vital tool for medicinal chemists.

METHODS

In order to gather scientific information on Imidazo[1,2-a] pyridines derivative, Google, PubMed, Scopus, Google Scholar, and other databases were searched. In the current study, the medicinal value and therapeutic effect of Imidazo[1,2-a] pyridines were investigated using above mentioned databases. The current study analyzed the detailed pharmacological activities of Imidazo[1,2-a] pyridine analogs through literature from diverse scientific research works.

RESULTS

Due to its wide range of biological activities, including antiulcer, anticonvulsant, antiprotozoal, anthelmintic, antiepileptic, antifungal, antibacterial, analgesic, antiviral, anticancer, anti-inflammatory, antituberculosis, and antitumor properties, imidazopyridine is one of the most significant structural skeletons in the field of natural and pharmaceutical products. An imidazopyridine scaffold serves as the basis for a number of therapeutically utilized medications, including zolpidem, alpidem, olprinone, zolimidine, and necopidem.

CONCLUSION

This comprehensive study covers the period of the last five years, and it sheds light on the developments and emerging pharmacological actions of Imidazo[1,2-a] pyridines. Additionally, the structure-activity relationship and molecular docking studies are carefully documented throughout the paper, providing medicinal chemists with a clear picture for developing new drugs.

Hemolysin from Aeromonas hydrophila enhances the host's serum enzyme activity and regulates transcriptional responses in the spleen of Cyprinus rubrofuscus

Aeromonas hydrophila is a conditional pathogen impacting public hygiene and safety. Hemolysin is a virulence factor of Aeromonas hydrophila that causes erythrocyte hemolysis, yet its transcriptional response to Cyprinus rubrofuscus remains unknown. Our investigation confirmed the hemolysis of hemolysin from A. hydrophila. Serum enzyme activity was evaluated weekly after C. rubrofuscus were immunized with hemolysin Ahh1. The results showed that the hemolysin enhances the serum superoxide dismutase (SOD), lysozyme (LZM), and catalase (CAT) activity, which reached a maximum on day 14. To elucidate the molecular interaction between hemolysin from A. hydrophila and the host, we performed transcriptome sequencing on the spleen of C. rubrofuscus 14 days post hemolysin infection. The total number of clean reads was 41.37 Gb, resulting in 79,832 unigenes with an N50 length of 1863 bp. There were 1982 significantly differentially expressed genes (DEGs), including 1083 upregulated genes and 899 downregulated genes. Transcript levels of the genes, such as LA6BL, CD2, and NLRC5, were significantly downregulated, while those of IL11, IL1R2, and IL8 were dramatically upregulated. The DEGs were mainly enriched in the immune disease, viral protein interaction with cytokine and cytokine receptor, and toll-like receptor pathways, suggesting that hemolysin stimulation can activate the transcriptional responses. RT-qPCR experiments results of seven genes, IL-8, STAT2, CTSK, PRF1, CXCL9, TLR5, and SACS, showed that their expression was highly concordant with RNA-seq data. We clarified for the first time the key genes and signaling pathways response to hemolysin from A. hydrophila, which offers strategies for treating and preventing diseases.

Imidazopyridine-Based Thiazole Derivatives as Potential Antidiabetic Agents: Synthesis, In Vitro Bioactivity, and In Silico Molecular Modeling Approach

A new series of thiazole derivatives (4a-p) incorporating imidazopyridine moiety was synthesized and assessed for their in vitro potential α-glucosidase potency using acarbose as a reference drug. The obtained results suggested that compounds 4a (docking score = -13.45), 4g (docking score = -12.87), 4o (docking score = -12.15), and 4p (docking score = -11.25) remarkably showed superior activity against the targeted α-glucosidase enzyme, with IC50 values of 5.57 ± 3.45, 8.85 ± 2.18, 7.16 ± 1.40, and 10.48 ± 2.20, respectively. Upon further investigation of the binding mode of the interactions by the most active scaffolds with the α-glucosidase active sites, the docking analysis was accomplished in order to explore the active cavity of the α-glucosidase enzyme. The interpretation of the results showed clearly that scaffolds 4a and 4o emerged as the most potent α-glucosidase inhibitors, with promising excellent binding interactions with the active site of the α-glucosidase enzyme. Furthermore, utilizing a variety of spectroscopic methods, such as 1H-NMR, 13C-NMR, and HREI-MS, the precise structures of the synthesized scaffolds were determined.

Synthetic transformation of 6-Fluoroimidazo[1,2-a]Pyridine-3-carbaldehyde into 6-Fluoroimidazo[1,2-a]Pyridine-Oxazole Derivatives: In vitro urease inhibition and in silico study

Purpose

Ulcer is a serious disease that is caused due to different bacteria and over usage of various NSAIDs which caused to reduce the defensive system of stomach. Therefore, some novel series are needed to overcome these issues.

Methods

Oxazole-based imidazopyridine scaffolds (4a-p) were designed and synthesized by two step reaction protocol and then subjected to urease inhibition profile (in vitro). All the newly afforded analogs (4a-p) were found potent and demonstrated moderate to significant inhibition profile.

Results

Particularly, the analogs 4i (IC₅₀ = 5.68 ± 1.66 μM), 4o (IC₅₀ = 7.11 ± 1.24 μM), 4 g (IC₅₀ = 9.41 ± 1.19 μM) and 4 h (IC₅₀ = 10.45 ± 2.57 μM) were identified to be more potent than standard thiourea drug (IC₅₀ = 21.37 ± 1.76 μM). Additionally, the variety of spectroscopic tools such as ¹H NMR, ¹³C NMR and HREI-MS analysis were employed to confirm the precise structures of all the newly afforded analogs.

Discussion

The structure-activity relationship (SAR) studies showed that analogs possess the substitution either capable of furnishing strong HB like -OH or had strong EW nature such as -CF₃ & -NO₂ groups displayed superior inhibitory potentials than the standard thiourea drug. A good PLI (protein-ligand interaction) profile was shown by most active analogs when subjected to molecular study against corresponding target with key significant interactions such as pi-pi stacking, pi-pi T shaped and hydrogen bonding.

Modification of 5-methylphenanthridium from benzothiazoles to indoles as potent FtsZ inhibitors: Broadening the antibacterial spectrum toward vancomycin-resistant enterococci

The death caused by pathogenic bacteria has always been a severe threat to mankind. The prevalence of drug resistance among bacteria underscores an urgent goal for new antibacterial agents with novel mode of action. Here we first designed and synthesized a class of benzothiazolyl-5-methylphenanthridium derivatives and evaluated their antibacterial activity. On this basis, we further designed and synthesized another class of novel indolyl-5-methylphenanthridium derivatives by optimizing the benzothiazolyl-5-methylphenanthridium core and evaluated their antibacterial activity targeting the bacterial cell division protein FtsZ. The results showed that the indolyl-5-methylphenanthridium derivatives had greatly improved activity against various drug-resistant bacterial strains including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus (VRE). Among them, compound C5 displayed excellent antibacterial activity against susceptible (MIC = 1 μg/mL), methicillin-resistant and clinical isolated S. aureus (MIC = 2 μg/mL). With low hemolytic activity towards mice red blood cells, C5 exhibited good antibacterial effect in vivo in preliminary pharmacodynamic assay. More importantly, C5 was difficult to induce bacterial resistance. Further mechanism studies proved that C5 could inhibit bacterial cell division by promoting FtsZ polymerization, leading to disorderly polymerization and disordered knots. Therefore, our findings suggest that this class of novel indolyl-5-methylphenanthridium derivatives are promising for future antibacterial agents.

Synthesis, Molecular Docking, BSA, and in-vitro reactivation study of imidazopyridine oxime against paraoxon inhibited acetylcholinesterase

AIM

To synthesize and evaluate the fused heterocyclic imidazopyridine oxime as a reactivator against paraoxon inhibited acetylcholinesterase.

BACKGROUND

Organophosphorus compounds (OPs) include parathion, malathion, chlorpyrifos, monocrotophos, and diazinon which are commonly used in agriculture for enhancing agricultural productivity via killing crop-damaging pests. However, people may get exposed to OPs pesticides unintentionally/intentionally via ingestion, inhalation or dermal. The current treatment regimen includes reactivator such as mono or bis-pyridinium oximes along with anticholinergic and an anticonvulsant drugs are recommended for the treatment of OP poisoning. Unfortunately, the drawback of the existing reactivator is that owing to the permanent charge present on the pyridinium makes them inefficient to cross the blood-brain barrier (BBB) and reactivate OP-inhibited central nervous system (CNS) acetylcholinesterase. Therefore, there is a need of reactivator that could cross the BBB and reactivate the OP inhibited acetylcholinesterase.

OBJECTIVE

The objectives of the study were synthesis, molecular docking, BSA binding and in-vitro estimation of oximes of various substituted imidazo [1,2-a]pyridine against paraoxon inhibited acetylcholinesterase.

METHOD

The reactivators were synthesized in three steps and characterized using various spectroscopic techniques. Molecular docking study was performed on 2WHP and 3ZLV PDB using Autodock tool. The acid dissociation constant (pKa) of oximes was calculated experimentally and drug-likeness properties of the oximes were calculated In silico using mole inspiration and Swiss ADME software. The binding of oximes with bovine serum albumin (BSA) was also investigated by UV-Vis spectrophotometer. The reactivation potential of the oximes was determined by in vitro enzymatic assay.

RESULT

in-silico study inferred that synthesized molecules fulfilled the parameters that required for a successful CNS drug candidate. Further, in-vitro enzymatic assay indicated reasonable reactivation potential of the oximes against paraoxon-inhibited AChE. The binding of oximes with bovine serum albumin (BSA) revealed static quenching of intrinsic fluorescence of BSA by oxime. The binding constant value and number of binding sites were found 0.24 mol-1 and 1 respectively.

CONCLUSION

The results of study concluded that this scaffold could be used for further designing of more efficient uncharged reactivators.