Comprehensive review in current developments of imidazole-based medicinal chemistry

Amino acid- and peptide-conjugated heterocyclic compounds: A comprehensive review of Synthesis Strategies and biological activities

Amino acids and peptides have long been recognized as promising candidates for therapeutic development due to their unique structural properties and high specificity. However, their clinical application is often limited by rapid enzymatic degradation, poor bioavailability, and suboptimal pharmacokinetics. Conjugating these biomolecules with heterocyclic compounds has emerged as a transformative strategy to enhance their stability, bioavailability, and overall therapeutic efficacy. This review highlights significant advancements since 2000 in the synthesis and biological applications of amino acid- and peptide-conjugated heterocyclic compounds These conjugates are categorized based on their nitrogen-, sulfur-, and oxygen-containing heterocyclic cores. Key synthetic methodologies, including amide bond formation, carbon-heteroatom coupling, and carbon-carbon bond formation, are discussed in detail. These conjugates exhibit enhanced pharmacological properties, with notable applications in antimicrobial, anticancer, and anti-inflammatory treatments. Despite these advancements, challenges such as synthetic complexity and potential toxicity remain. Future research should prioritize refining synthetic methodologies and leveraging underexplored heterocycles to unlock broader therapeutic applications. Peptide-heterocycle conjugates represent a promising approach to overcoming persistent challenges in modern drug development.

Benzo-α-pyrone-derived multitargeting actions to enhance the antibacterial performance of sulfanilamides against Escherichia coli

A novel class of benzopyrone-sulfanilamide hybrids was synthesized from phenols via multi-step reactions. Some prepared compounds effectively suppressed bacterial growth at low concentrations, and especially, sulfanilamide-hybridized 2-methyl-5-nitroimidazolyl benzopyrone 11c exhibited significant inhibitory potency against Escherichia coli (MIC = 0.0022 mM), which was 11-fold more active than clinical norfloxacin. Furthermore, compound 11c showed negligible hemolytic activity, low cytotoxicity and no drug resistance. Mechanistic studies indicated that the highly active 11c disrupted bacterial membrane integrity, reduced metabolic activity, bound DNA grooves to inhibit replication without the ability to cleave DNA, and induced reactive oxygen species (ROS) accumulation, collectively leading to bacterial death. These results highlight the potential of sulfanilamide-hybridized benzopyrones as multitarget antibacterial agents, warranting further development to combat bacterial infections.

Exploring USFDA-Approved Imidazole-Based Small Molecules in Drug Discovery: A Mini Perspective

In the present work, we have explored the importance of the imidazole ring and its importance in drug discovery, citing the key approvals in the present decade (2013-2024). The pharmacological attribution for the approved drugs revealed that out of 20 approved drugs, 45% of the approvals were made as anti-infectives, followed by approvals under the category of genetic and metabolic disorders, sexual endocrine disorders, anticancer, and to treat blood pressure, gastrointestinal disorders, and neurological conditions. Most approved drugs were dispensed through solid dosage forms (13) and thus had predominantly oral routes beside others. The metabolism pattern revealed that the drugs undergo metabolism via the involvement of multiple enzymes, where CYP3A4 and CYP3A5 were the core enzymes. The excretion pattern of these drugs revealed that the drugs are majorly excreted via the fecal route. The chemical analysis showed that pyrrolidine/pyrrole was the major heterocycle in the approved drugs, followed by the indole ring in the hybridization. Considering the substitution pattern, most drugs possessed amide, amines, and fluoro group as the functional substitution with the 2,4-substitution pattern seen in most approved drugs. Besides this, the three approved drugs were found to possess chiral centers and exhibit chirality. The article also expanded to cover the synthetic routes and metabolic routes for this versatile ring system and case studies for its utility to serve as bioisostere in drug discovery. Furthermore, this article also presents the receptor-ligand interactions of imidazole-based drugs with various target receptors. The present article is, therefore, put forth to assist medicinal chemists and chemists working in drug discovery of this versatile ring system.

Synthesis of Diverse Imidazole and Quinoxaline Derivatives via Iodine-Mediated Cyclization Reactions

A novel approach for the synthesis of diverse substituted imidazoles and quinoxalines via an iodine-promoted cyclization reaction is described. The methodology showcases a broad substrate scope, achieving moderate to very good yields for biologically relevant imidazoles and quinoxalines. Notably, iodine serves as both an iodinating agent and an oxidizing agent, as shown by a mechanistic study. The current methodology is capable of being scaled up to gram quantities, operates in a metal-free environment under mild reaction conditions, and utilizes readily available substrates.

A comprehensive insight into naphthalimides as novel structural skeleton of multitargeting promising antibiotics

The globally growing antimicrobial resistance seriously threatens human health, increasing efforts have been devoting to the development of novel antibiotics. Naphthalimides contain a special skeleton of cyclic double imides and the naphthalene framework, this unique structure can exert multitargeting abilities which are helpful to overcome the escalating issue of resistance. Therefore, research in connection with the development of naphthalimides as novel antimicrobial agents is becoming progressively active. It has been revealed that naphthalimides as novel structural skeleton of multitargeting promising antibiotics could not only target DNAs and enzymes, disturb membrane, produce reactive oxygen species, etc. suggesting the multitargeting actions which do not induce resistance, but also show a broad antimicrobial spectrum with safety profile and pharmacokinetic characteristics, implying large potential as a new type of antibiotics via continuous efforts toward antimicrobial naphthalimides. This review presents naphthalimides as a new type of potential antimicrobial agents and discusses rational design strategies, structure-activity relationships, and mechanisms of action, with a comprehensive view to providing a new insight for in the rational design of efficient, broad-spectrum, and low-toxic naphthalimide antibiotics.

Aggregation-induced enhanced emission (AIEE), pH sensing and selective detection of sulfuric acid of novel imidazole-based surrogates made via microwave-assisted synthesis

A novel series of imidazole derivatives (4a-d) was synthesized via a microwave-assisted synthesis and whose structures were elucidated using 1H and 13C NMR, ESI-HRMS, and FT-IR spectroscopy. Photophysical characterization revealed absorption peaks around 305 nm and 327-365 nm, with strong photoluminescence (PL) emission maxima ranging between 435 and 453 nm. Aggregation-induced enhanced emission (AIEE) behavior was observed in THF/H2O mixtures, where 4a-c showed maximal fluorescence at certain solvent ratios, indicating aggregate formation. 4d disclosed a wavelength shift from 408 to 460 nm along with an enhanced emission, which is attributed to restricted intramolecular rotation (RIR), as confirmed by viscosity studies. Fluorescence lifetime and dynamic light scattering (DLS) measurements further supported the aggregation process, with particle sizes between 100 nm and 720 nm. Density functional theory (DFT) calculations validated electronic conjugation, showing HOMO-LUMO bandgaps (ΔE) of approximately 2.01-2.23 eV for 4a-d. Compound 4a exhibited the largest HOMO-LUMO energy gap of 2.23 eV, indicating greater electronic stability and enhanced emission efficiency upon aggregation. In contrast, compound 4d, with the smallest energy gap of 2.01 eV, suggests higher reactivity and better sensitivity to aggregation phenomena. This characteristic renders 4d particularly advantageous for sensing applications where rapid responsiveness to environmental variations is critical. pH sensing studies demonstrated the stability of 4a-d over a broad pH range, with 4d showing a 47 nm red shift in highly acidic conditions besides a selectivity for sulfuric acid detection. Investigation of sulfuric acid detection limit was studied, revealing a capacity for 4a-d to detect an acidic concentration as low as 16.5 μM. Stability and practical applicability of 4d compound as a sensor are further confirmed through reversibility and repeatability tests which reveal the possibility to regenerate the imidazole derivative even after several uses.

Oxazole and isoxazole-containing pharmaceuticals: targets, pharmacological activities, and their SAR studies

Oxazole, a five-membered aromatic heterocycle featuring a nitrogen and an oxygen atom separated by a carbon atom, and its isomer isoxazole, with directly attached oxygen and nitrogen atoms, have been pivotal in medicinal chemistry. Over the past few decades, the U.S. Food and Drug Administration (FDA) has approved more than 20 drugs containing these nuclei for various clinical conditions, including Tafamidis and Oxaprozin. Due to their unique physicochemical properties, these drugs often exhibit superior pharmacokinetic profiles and pharmacological effects compared to those with similar heterocycles. This review provides a comprehensive overview of all FDA-approved drugs containing oxazole and isoxazole nuclei, focusing on their pharmacological activities and structure-activity relationships.

Antimicrobial Peptides and Their Mimetics: Promising Candidates of Next-Generation Therapeutic Agents Combating Multidrug-Resistant Bacteria

The increasing morbidity and mortality caused by multidrug-resistant bacteria alerts human beings to the fact that conventional antibiotics are no longer reliable and effective alternatives are imperatively needed. Owing to wide range of sources, diverse structures, and unique mode of action, antimicrobial peptides have been highly anticipated and extensively studied in recent years. Besides, the integration of artificial intelligence helps researchers gain access to the vast unexplored chemical space, which opens more opportunities for the optimization and design of novel structures. Moreover, Due to advances in chemistry and synthetic biology, researchers have also begun to focus on the potential of chemical mimetics of antimicrobial peptides. In this review, a comprehensive discussion about natural and synthesized antimicrobial peptides as well as their chemical mimetics is made, so as to provide a comprehensive summary of this field and inspire follow-up research.

Innovative Syntheses and Reactivity of Propiolamidines

Polydentate ligands with nitrogen donor atoms have possibly given rise to the largest group of coordination complexes described. Among these ligands, amidinates represent a nitrogenated version of carboxylates and allow the formation of complexes with most elements in the periodic table, adopting chelate or bridge coordination modes. The precursors of these ligands, amidines, can present an alkynyl group as the substituent of their central atom, R'N=C(C≡CR)NHR', which provides an additional point of reactivity for these molecules, as well as a different electronic behavior compared to conventional amidines with alkyl groups on the central carbon atom of the amidine group. These propiolamidines have been obtained through classical stoichiometric organic synthesis procedures or, with greater atomic economy, through catalytic procedures based on Main Group, Transition, or Rare Earth metals. This work reviews these synthesis methods, as well as the reactivity in the obtention of new, more complex heterocyclic organic molecules.

On-demand imidazolidinyl urea-based tissue-like, self-healable, and antibacterial hydrogels for infectious wound care

Bacterial wound infections are a growing challenge in healthcare, posing severe risks like systemic infection, organ failure, and sepsis, with projections predicting over 10 million deaths annually by 2050. Antibacterial hydrogels, with adaptable extracellular matrix-like features, are emerging as promising solutions for treating infectious wounds. However, the antibacterial properties of most of these hydrogels are largely attributed to extrinsic agents, and their mechanisms of action remain poorly understood. Herein we introduce for the first time, modified imidazolidinyl urea (IU) as the polymeric backbone for developing tissue-like antibacterial hydrogels. As-designed hydrogels behave tissue-like mechanical features, outstanding antifreeze behavior, and rapid self-healing capabilities. Molecular dynamics (MD) simulation and density functional theory (DFT) calculation were employed to well-understand the extent of H-bonding and metal-ligand coordination to finetune hydrogels' properties. In vitro studies suggest good biocompatibility of hydrogels against mouse fibroblasts & human skin, lung, and red blood cells, with potential wound healing capacity. Additionally, the hydrogels exhibit good 3D printability and remarkable antibacterial activity, attributed to concentration dependent ROS generation, oxidative stress induction, and subsequent disruption of bacterial membrane. On top of that, in vitro biofilm studies confirmed that developed hydrogels are effective in preventing biofilm formation. Therefore, these tissue-mimetic hydrogels present a promising and effective platform for accelerating wound healing while simultaneously controlling bacterial infections, offering hope for the future of wound care.

Deletion of bZIP Transcription Factor PratfA Reveals Specialized Metabolites Potentially Regulating Stress Response in Penicillium raistrickii

Fungal secondary metabolism (SM) is highly correlated with physiological processes that are typically regulated by pleiotropic regulators. In this study, we purposefully altered PratfA, a crucial regulator associated with oxidative stress in Penicillium raistrickii CGMCC 3.1066. After the knockout of PratfA, a novel polyketide (PK) raistrilide A (1) and the known nonribosomal peptide (NRP) tunicoidine (2) subsequently disappeared. Notably, compound 1 is a rare octaketone derivative and contains two unsubstituted cis-double bonds, demonstrating its unique biosynthetic mechanism. The knockout of PratfA resulted in the disappearance of 1-2 and greatly increased the susceptibility of ΔPratfA mutant strain to oxidative stress, rendering it nearly impossible to survive in such environments. At present, the OE⸬PratfA strain showed no phenotypic or oxidative stress sensitivity differences compared to the wild-type strain. Our findings highlight that the oxidative-stress-related transcription factor (TF) PratfA influences SM pathways in P. raistrickii. The manipulation of regulatory factors can guide the discovery of novel natural products (NPs).

Discovery of Quinazolone Pyridiniums as Potential Broad-Spectrum Antibacterial Agents

The overprescription of antibiotics in medicine and agriculture has accelerated the development and spread of antibiotic resistance in bacteria, which severely limits the arsenal available to clinicians for treating bacterial infections. This work discovered a new class of heteroarylcyanovinyl quinazolones and quinazolone pyridiniums to surmount the increasingly severe bacterial resistance. Bioactive assays manifested that the highly active compound 19a exhibited strong inhibition against MRSA and Escherichia coli with extremely low MICs of 0.5 μg/mL, being eightfold more active than that of norfloxacin (MICs = 4 μg/mL). The highly active 19a with rapid bactericidal properties displayed imperceptible resistance development trends, negligible hemolytic toxicity, and effective biofilm inhibitory effects. Preliminary explorations on antibacterial mechanisms revealed that compound 19a could cause membrane damage, embed in intracellular DNA to hinder bacterial DNA replication, and induce metabolic dysfunction. Surprisingly, active 19a was found to trigger the conformational change in PBP2a of MRSA to open the active site, which might account for its high inhibition against MRSA. In addition, the little effect of molecule 19a on the production of reactive oxygen species indicated that bacterial death was not caused by oxidative stress. The above comprehensive analyses highlighted the large potential of quinazolone pyridiniums as multitargeting broad-spectrum antibacterial agents.

Catalyst-Free Construction of Imidazole-Pyrrolo[1,2-a]pyrazine Hybrid, 2,6-Disubstituted Imidazo[1,2-a]pyrrolo[2,1-c]pyrazine via Regioselective Annulative Functionalizations

Highly efficient catalyst-free annulative functionalization approaches to a novel imidazole-pyrrolo[1,2-a]pyrazine hybrid structure were devised from the reaction of β-enaminone with propargylamine where regioselective conjugate substitution of β-enaminone with propargylamine followed by cycloisomerization proceeded smoothly in a domino fashion to construct two heterocyclic moieties (pyrazine and imidazole) via successive formation of three C-N bonds, leading to the target tricyclic skeleton.

An insight into recent developments in imidazole based heterocyclic compounds as anticancer agents: Synthesis, SARs, and mechanism of actions

Among all non-communicable diseases, cancer is ranked as the second most common cause of death and is rising constantly. While cancer treatments mainly include radiation therapy, chemotherapy, and surgery; chemotherapy is considered the most commonly employed and effective treatment. Most of the chemotherapeutic agents are azoles based compounds and imidazole is one such insightful azole. The anticancer properties of imidazole-based compounds have been thoroughly explored in recent years and all monosubstituted, disubstituted, trisubstituted, and tetrasubstituted imidazoles have been explored for their anticancer activities. Along with these compounds, other imidazole-based compounds like 1,3-dihydro-2H-imidazole-2-thiones, imidazolones, and poly imidazole compounds have also been explored for their anticancer activities. The activities of these compounds are heavily influenced by their structural resemblance to combretastatin 4A and ABI (2-aryl-4-benzoyl-imidazole). The lead compounds were highly active on breast, gastric, colon, ovarian, cervical, bone marrow, melanoma, prostate, lung, leukemic, neuroblastoma, liver, Ehrlich, melanoma, and pancreatic cancers. The targets of these leads like tubulin, heme oxygenases, VEGF, tyrosine kinases, EGFR, and others have also been explored. The exploration of the anticancer potential of substituted imidazole compounds is the main topic of this review including synthesis, SAR, and mechanism.

Synthesis and Biological Evaluation of Novel Imidazole Derivatives as Antimicrobial Agents

Imidazole derivatives are considered potential chemical compounds that could be therapeutically effective against several harmful pathogenic microbes. The chemical structure of imidazole, with a five-membered heterocycle, three carbon atoms, and two double bonds, tends to show antibacterial activities. In the present study, novel imidazole derivatives were designed and synthesized to be evaluated as antimicrobial agents owing to the low number of attempts to discover new antimicrobial agents and the emerging cases of antimicrobial resistance. Two imidazole compounds were prepared and evaluated as promising candidates regarding in vitro cytotoxicity against human skin fibroblast cells and antimicrobial activity against several bacterial strains. The synthesized imidazole derivatives were chemically identified using nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR). The results demonstrated a relatively high cell viability of one of the imidazole derivatives, i.e., HL2, upon 24 and 48 h cell exposure. Both derivatives were able to inhibit the growth of the tested bacterial strains. This study provides valuable insight into the potential application of imidazole derivatives for treating microbial infections; however, further in vitro and in vivo studies are required to confirm their safety and effectiveness.

Synthesis and antibacterial medicinal evaluation of carbothioamido hydrazonyl thiazolylquinolone with multitargeting antimicrobial potential to combat increasingly global resistance

The global microbial resistance is a serious threat to human health, and multitargeting compounds are considered to be promising to combat microbial resistance. In this work, a series of new thiazolylquinolones with multitargeting antimicrobial potential were developed through multi-step reactions using triethoxymethane and substituted anilines as start materials. Their structures were confirmed by 1H NMR, 13C NMR and HRMS spectra. Antimicrobial evaluation revealed that some of the target compounds could effectively inhibit microbial growth. Especially, carbothioamido hydrazonyl aminothiazolyl quinolone 8a showed strong inhibitory activity toward drug-resistant Staphylococcus aureus with MIC value of 0.0047 mM, which was 5-fold more active than that of norfloxacin. The highly active compound 8a exhibited negligible hemolysis, no significant toxicity in vitro and in vivo, low drug resistance, as well as rapidly bactericidal effects, which suggested its favorable druggability. Furthermore, compound 8a was able to effectively disrupt the integrity of the bacterial membrane, intercalate into DNA and inhibit the activity of topoisomerase IV, suggesting multitargeting mechanism of action. Compound 8a could form hydrogen bonds and hydrophobic interactions with DNA-topoisomerase IV complex, indicating the insertion of aminothiazolyl moiety was beneficial to improve antibacterial efficiency. These findings indicated that the active carbothioamido hydrazonyl aminothiazolyl quinolone 8a as a chemical therapeutic candidate demonstrated immense potential to tackle drug-resistant bacterial infections.

Metal-free approach for imidazole synthesis via one-pot N-α-C(sp3)-H bond functionalization of benzylamines

A metal-free one-pot method is established for the synthesis of tetrasubstituted imidazoles from the reaction of arylmethylamines and 1,2-dicarbonyls/benzoin. The N-α-C(sp3)-H bond functionalization of arylmethylamines using a catalytic amount of AcOH afforded polysubstituted imidazoles under aerobic conditions in significant yields of up to 95%.

Imidazoles are Tunable Nucleofuges for Developing Tyrosine-Reactive Electrophiles

Imidazole-1-sulfonyl and -sulfonate (imidazylate) are widely used in synthetic chemistry as nucleofuges for diazotransfer, nucleophilic substitution, and cross-coupling reactions. The utility of these reagents for protein bioconjugation, in contrast, have not been comprehensively explored and important considering the prevalence of imidazoles in biomolecules and drugs. Here, we synthesized a series of alkyne-modified sulfonyl- and sulfonate-imidazole probes to investigate the utility of this electrophile for protein binding. Alkylation of the distal nitrogen activated the nucleofuge capability of the imidazole to produce sulfonyl-imidazolium electrophiles that were highly reactive but unstable for biological applications. In contrast, arylsulfonyl imidazoles functioned as a tempered electrophile for assessing ligandability of select tyrosine and lysine sites in cell proteomes and when mated to a recognition element could produce targeted covalent inhibitors with reduced off-target activity. In summary, imidazole nucleofuges show balanced stability and tunability to produce sulfone-based electrophiles that bind functional tyrosine and lysine sites in the proteome.

Synthesis and characterization of 2-(anthracene-9-yl)-4,5-diphenyl-1H-imidazole derivatives as environmentally sensitive fluorophores

2-(Anthracene-9-yl)-4,5-diphenyl-1H-imidazole (ADPI) provides an intriguing molecular platform for developing organic fluorophores with diverse properties and fluorescence performances. However, derivatives of ADPI have not yet been well explored and extensive studies are warranted. To shed more light on this, we have synthesized a series of π-extended ADPIs through a concise synthetic route involving an efficient cross-condensation reaction followed by Pd-catalyzed Suzuki cross-coupling. The obtained compounds were subjected to X-ray single crystallographic analysis to understand their molecular conformational and solid-state packing properties. Furthermore, UV-Vis absorption and fluorescence spectroscopic analyses were conducted. Our experimental results have disclosed interesting solvatofluorochromic properties of these compounds which are useful for solvent polarity-sensitive applications. The presence of an amphoteric imidazolyl group in the ADPI derivatives also renders them sensitive fluorescence responses to strong protic acids (e.g., trifluoroacetic acid) as well as fluoride anion. It transpires that the fluorescence changes are dependent on the functional groups attached to the ADPI core, suggesting a bottom-up molecular tuning approach for development of fluorophores and chemosensors with diverse functions.

Substituent effects and electron delocalization in five-membered N-heterocycles

Five-membered N-heterocycles are principal constituents of many compounds of vital importance in various fields of chemistry, biochemistry or pharmaceutical chemistry. For this reason, unequivocal identification of structural factors determining electron donating/withdrawing properties of specific groups attached to the heterocyclic moiety becomes an utmost need together with elucidation of the substitution-induced changes in cyclic and noncyclic electron delocalization. Thus, quantum-chemical calculations were performed for pyrrole, imidazole, pyrazole, 1,2,3- and 1,2,4-triazole, and their C-substituted mono-derivatives (X = NO2, CN, Br, Cl, F, SH, OH, NH2). The obtained dataset contains information on substituent properties (cSAR - charge of the substituent active region method), delocalization (EDDB - electron density of delocalized bonds) and geometry. It follows that the positions of endocyclic N atoms relative to the substituent influence in the most profound manner its properties. N atoms in ortho positions significantly boost the electron-donation and weaken the electron-withdrawal by induction. Another factor is the resonance charge transfer from the substituents to N atoms, and then inductive interactions with further (non-ortho) N atoms. While substituent constants correctly describe the changes of their properties (including those attached to the heterocycles), a testimony to Hammett's genius, quantum chemical models must be used to quantify the exact properties. In most heterocycles, electron-donating substituents hinder the cyclic delocalization, except 4-pyrazole. The applied recent EDDB method allows to study this phenomenon in detail. It follows that changes in aromaticity originate from the π-electronic effects of substituents on the ring bonds, changing the localization and delocalization of particular bonds in a correlated manner.

Recent Advances in Design and Development of Diazole and Diazine Based Fungicides (2014-2023)

With fungal diseases posing a major threat to agricultural production, the application of fungicides to control related diseases is often considered necessary to ensure the world's food supply. The search for new bioactive agents has long been a priority in crop protection due to the continuous development of resistance against currently used types of active compounds. Heterocyclic compounds are an inseparable part of the core structures of numerous lead compounds, these rings constitute pharmacophores of a significant number of fungicides developed over the past decade by agrochemists. Among heterocycles, nitrogen-based compounds play an essential role. To date, diazole (imidazole and pyrazole) and diazine (pyrimidine, pyridazine, and pyrazine) derivatives make up an important series of synthetic fungicides. In recent years, many reports have been published on the design, synthesis, and study of the fungicidal activity of these scaffolds, but there was a lack of a comprehensive classified review on nitrogen-containing scaffolds. Regarding this issue, here we have reviewed the published articles on the fungicidal activity of the diazole and diazine families. In current review, we have classified the molecules synthesized so far based on the size of the ring.

Synthesis, Characterization, and Cytotoxicity Evaluation of Novel Water-Soluble Cationic Platinum(II) Organometallic Complexes with Phenanthroline and Imidazolic Ligands

Platinum-based chemotherapeutic agents are widely used in the treatment of cancer. However, their effectiveness is limited by severe adverse reactions, drug resistance, and poor water solubility. This study focuses on the synthesis and characterization of new water-soluble cationic monofunctional platinum(II) complexes starting from the [PtCl(η1-C2H4OEt)(phen)] (1, phen=1,10-phenanthroline) precursor, specifically [Pt(NH3)(η1-C2H4OEt)(phen)]Cl (2), [Pt(1-hexyl-1H-imidazole)(η1-C2H4OEt)(phen)]Cl (3), and [Pt(1-hexyl-1H-benzo[d]imidazole)(η1-C2H4OEt)(phen)]Cl (4), which deviate from traditional requirements for antitumor activity. These complexes were evaluated for their cytotoxic effects in comparison to cisplatin, using immortalized cervical adenocarcinoma cells (HeLa), human renal carcinoma cells (Caki-1), and normal human renal cells (HK-2). While complex 2 showed minimal effects on the cell lines, complexes 3 and 4 demonstrated higher cytotoxicity than cisplatin. Notably, complex 4 displayed the highest cytotoxicity in both cancer and normal cell lines. However, complex 3 exhibited the highest selectivity for renal tumor cells (Caki-1) among the tested complexes, compared to healthy cells (HK-2). This resulted in a significantly higher selectivity than that of cisplatin and complex 4. Therefore, complex 3 shows potential as a leading candidate for the development of a new generation of platinum-based anticancer drugs, utilizing biocompatible imidazole ligands while demonstrating promising anticancer properties.

Unique aminothiazolyl coumarins as potential DNA and membrane disruptors towards Enterococcus faecalis

Aminothiazolyl coumarins as potentially new antimicrobial agents were designed and synthesized in an effort to overcome drug resistance. Biological activity assay revealed that some target compounds exhibited significantly inhibitory efficiencies toward bacteria and fungi including drug-resistant pathogens. Especially, aminothiazolyl 7-propyl coumarin 8b and 4-dichlorobenzyl derivative 11b exhibited bactericidal potential (MBC/MIC = 2) toward clinically drug-resistant Enterococcus faecalis with low cytotoxicity to human lung adenocarcinoma A549 cells, rapidly bactericidal effects and no obvious bacterial resistance development against E. faecalis. The preliminary antibacterial action mechanism studies suggested that compound 11b was able to disturb E. faecalis membrane effectively, and interact with bacterial DNA isolated from resistant E. faecalis through noncovalent bonds to cleave DNA, thus inhibiting the growth of E. faecalis strain. Further molecular modeling indicated that compounds 8b and 11b could bind with SER-1084 and ASP-1083 residues of gyrase-DNA complex through hydrogen bonds and hydrophobic interactions. Moreover, compound 11b showed low hemolysis and in vivo toxicity. These findings of aminothiazolyl coumarins as unique structural scaffolds might hold a large promise for the treatments of drug-resistant bacterial infection.

Synthesis and Biological Evaluation of New Compounds with Nitroimidazole Moiety

Heterocyclic compounds, particularly those containing azole rings, have shown extensive biological activity, including anticancer, antibacterial, and antifungal properties. Among these, the imidazole ring stands out due to its diverse therapeutic potential. In the presented study, we designed and synthesized a series of imidazole derivatives to identify compounds with high biological potential. We focused on two groups: thiosemicarbazide derivatives and hydrazone derivatives. We synthesized these compounds using conventional methods and confirmed their structures via nuclear magnetic resonance spectroscopy (NMR), MS, and elemental analysis, and then assessed their antibacterial and antifungal activities in vitro using the broth microdilution method against Gram-positive and Gram-negative bacteria, as well as Candida spp. strains. Our results showed that thiosemicarbazide derivatives exhibited varied activity against Gram-positive bacteria, with MIC values ranging from 31.25 to 1000 µg/mL. The hydrazone derivatives, however, did not display significant antibacterial activity. These findings suggest that structural modifications can significantly influence the antimicrobial efficacy of imidazole derivatives, highlighting the potential of thiosemicarbazide derivatives as promising candidates for further development in antibacterial therapies. Additionally, the cytotoxic activity against four cancer cell lines was evaluated. Two derivatives of hydrazide-hydrazone showed moderate anticancer activity.

Anti-Infection of Oral Microorganisms from Herbal Medicine of Piper crocatum Ruiz & Pav

The WHO Global Status Report on Oral Health 2022 reveals that oral diseases caused by infection with oral pathogenic microorganisms affect nearly 3.5 billion people worldwide. Oral health problems are caused by the presence of S. mutans, S. sanguinis, E. faecalis and C. albicans in the oral cavity. Synthetic anti-infective drugs have been widely used to treat oral infections, but have been reported to cause side effects and resistance. Various strategies have been implemented to overcome this problem. Synthetic anti-infective drugs have been widely used to treat oral infections, but they have been reported to cause side effects and resistance. Therefore, it is important to look for safe anti-infective alternatives. Ethnobotanical and ethnopharmacological studies suggest that Red Betel leaf (Piper crocatum Ruiz & Pav) could be a potential source of oral anti-infectives. This review aims to discuss the pathogenesis mechanism of several microorganisms that play an important role in causing health problems, the mechanism of action of synthetic oral anti-infective drugs in inhibiting microbial growth in the oral cavity, and the potential of red betel leaf (Piper crocatum Ruiz & Pav) as an herbal oral anti-infective drug. This study emphasises the importance of researching natural components as an alternative treatment for oral infections that is more effective and can meet global needs.

Possible adverse events of imidazole antifungal drugs during treatment of vulvovaginal candidiasis: analysis of the FDA Adverse Event Reporting System

Azole antifungal drugs are commonly used to treat vulvovaginal candidiasis (VVC). The nephrotoxicity and developmental toxicity of azole drugs have not been systematically analyzed in the real world. We used the FDA Adverse Event Reporting System (FAERS) to investigate the adverse events (AEs) associated with imidazole therapy for VVC. FAERS data (from quarter 1 2004 to quarter 3 2022) were retrieved using OpenVigil 2.1, and AEs were retrieved and standardized according to the Medical Dictionary for Regulatory Activities (MedDRA). In the top 10 System Organ Class (SOC), all four drugs have been found to have kidney and urinary system diseases and pregnancy. We found significant signals, including clotrimazole [bladder transitional cell carcinoma, (report odds ratio, ROR = 291.66)], [fetal death, (ROR = 10.28)], ketoconazole[nephrogenic anemia (ROR = 22.1)], [premature rupture of membranes (ROR = 22.91 46.45, 11, 3)], Miconazole[hematuria (ROR = 19.03)], [neonatal sepsis (ROR = 123.71)], [spontaneous abortion (ROR = 5.98)], Econazole [acute kidney injury (ROR = 4.41)], [spontaneous abortion (ROR = 19.62)]. We also discovered new adverse reactions that were not reported. Therefore, when using imidazole drugs for treatment, it is necessary to closely monitor the patient's renal function, pay attention to the developmental toxicity of the fetus during pregnancy, and be aware of potential adverse reactions that may occur.

Development of Membrane-Targeting Fluorescent 2-Phenyl-1H-phenanthro[9,10-d]imidazole-Antimicrobial Peptide Mimic Conjugates against Methicillin-Resistant Staphylococcus aureus

The escalation of multidrug-resistant bacterial infections, especially infections caused by methicillin-resistant Staphylococcus aureus (MRSA), underscores the urgent need for novel antimicrobial drugs. Here, we synthesized a series of amphiphilic 2-phenyl-1H-phenanthro[9,10-d]imidazole-antimicrobial peptide (AMP) mimic conjugates (III1-30). Among them, compound III13 exhibited excellent antibacterial activity against G+ bacteria and clinical MRSA isolates (MIC = 0.5-2 μg/mL), high membrane selectivity, and low toxicity. Additionally, compared with traditional clinical antibiotics, III13 demonstrated rapid bactericidal efficacy and was less susceptible to causing bacterial resistance. Mechanistic studies revealed that III13 targets phosphatidylglycerol (PG) on bacterial membranes to disrupt membrane integrity, leading to an increase in intracellular ROS and leakage of proteins and DNA, ultimately causing bacterial cell death. Furthermore, III13 possessed good fluorescence properties with potential for further dynamic monitoring of the antimicrobial process. Notably, III13 showed better in vivo efficacy against MRSA compared to vancomycin, suggesting its potential as a promising candidate for anti-MRSA medication.

Click chemistry beyond metal-catalyzed cycloaddition as a remarkable tool for green chemical synthesis of antifungal medications

Click chemistry is widely used for the efficient synthesis of 1,4-disubstituted-1,2,3-triazole, a well-known scaffold with widespread biological activity in the pharmaceutical sciences. In recent years, this magic ring has attracted the attention of scientists for its potential in designing and synthesizing new antifungal agents. Despite scientific and medical advances, fungal infections still account for more than 1.5 million deaths globally per year, especially in people with compromised immune function. This increasing trend is definitely related to a raise in the incidence of fungal infections and prevalence of antifungal drug resistance. In this condition, an urgent need for new alternative antifungals is undeniable. By focusing on the main aspects of reaction conditions in click chemistry, this review was conducted to classify antifungal 1,4-disubstituted-1,2,3-triazole hybrids based on their chemical structures and introduce the most effective triazole antifungal derivatives. It was notable that in all reactions studied, Cu(I) catalysts generated in situ by the reduction in Cu(II) salts or used copper(I) salts directly, as well as mixed solvents of t-BuOH/H2O and DMF/H2O had most application in the synthesis of triazole ring. The most effective antifungal activity was also observed in fluconazole analogs containing 1,2,3-triazole moiety and benzo-fused five/six-membered heterocyclic conjugates with a 1,2,3-triazole ring, even with better activity than fluconazole. The findings of structure-activity relationship and molecular docking of antifungal derivatives synthesized with copper-catalyzed azide-alkyne cycloaddition (CuAAC) could offer medicinal chemistry scientists valuable data on designing and synthesizing novel triazole antifungals with more potent biological activities in their future research.

Exploring the Synthetic and Antioxidant Potential of 1,2-Disubstituted Benzimidazoles Using [Et3NH][HSO4] Ionic Liquid Catalyst

An [Et3NH][HSO4] ionic-liquid catalyzed, intermolecular C-N bond formation for 1,2-disubstituted benzimidazole synthesis was achieved by the reaction of OPD and substituted aldehydes at ambient reaction conditions. Operational simplicity, use of easily available substrate and reagents, good yields (74-95 %) in short reaction time (4-18 min), simple work-up, and column chromatographic free synthesis are the remarkable features of this new protocol. The applicability of [Et3NH][HSO4] ionic-liquid as a green and inexpensive catalyst with good recyclability and compatibility with a broad range of functional group having heteroatom, electron-withdrawing, and electron-releasing groups manifested the sustainability, eco-friendliness, and efficiency of the present methodology. Moreover, the antioxidant studies of the synthesized compounds using DPPH and ABTS assays were appealing and several synthesized compounds showed significant antioxidant activity.

Three-component cascade reaction of 3-ketonitriles, 2-unsubstituted imidazole N-oxides, and aldehydes

A three-component condensation of 2-unsubstituted imidazole N-oxides, 3-ketonitriles, and aldehydes is described. The reaction proceeds via sequential Knoevenagel condensation/Michael addition under mild, catalyst-free conditions with various substrates. Furthermore, the corresponding 2-functionalized imidazole N-oxides can be further dehydrated to (Z)-2-aroyl-3-(1H-imidazol-2-yl)-acrylonitriles, which may also be directly prepared by changing the reaction conditions as a cascade of Knoevenagel condensation/Michael addition/dehydration.

Synthesis of 1-Benzyl-2,4-diarylimidazole through I2/CuI-Catalyzed Cyclization of Benzylamine and Hydrazone

In this paper, we report an innovative method for synthesizing 1-benzyl-2,4-diarylimidazole utilizing 1-phenylethanone-2-(2-pyridinyl) hydrazine and benzylamine, catalyzed by an I2/CuI system. This approach represents a significant departure from traditional methods for synthesizing polysubstituted imidazoles; it employs the I2/CuI catalyst to replace rare metal catalysts, thereby achieving high yields of substitution products (≤85%). This method for the generation of 1,2,4-triimidazole derivatives is characterized by its exceptional chemical selectivity and extensive substrate compatibility.

Mutual influence of non-covalent interactions formed by imidazole: A systematic quantum-chemical study

Imidazole is a five-membered heterocycle that is part of a number of biologically important molecules such as the amino acid histidine and the hormone histamine. Imidazole has a unique ability to participate in a variety of non-covalent interactions involving the NH group, the pyridine-like nitrogen atom or the π-system. For many biologically active compounds containing the imidazole moiety, its participation in formation of hydrogen bond NH⋯O/N and following proton transfer is the key step of mechanism of their action. In this work a systematic study of the mutual influence of various paired combinations of non-covalent interactions (e.g., hydrogen bonds and π-interactions) involving the imidazole moiety was performed by means of quantum chemistry (PW6B95-GD3/def2-QZVPD) for a series of model systems constructed based on analysis of available x-ray data. It is shown that for considered complexes formation of additional non-covalent interactions can only enhance the proton-donating ability of imidazole. At the same time, its proton-accepting ability can be both enhanced and weakened, depending on what additional interactions are added to a given system. The mutual influence of non-covalent interactions involving imidazole can be classified as weak geometric and strong energetic cooperativity-a small change in the length of non-covalent interaction formed by imidazole can strongly influence its strength. The latter can be used to develop methods for controlling the rate and selectivity of chemical reactions involving the imidazole fragment in larger systems. It is shown that the strong mutual influence of non-covalent interactions involving imidazole is due to the unique ability of the imidazole ring to effectively redistribute electron density in non-covalently bound systems with its participation.

Synthesis and in silico inhibitory action studies of azo-anchored imidazo[4,5-b]indole scaffolds against the COVID-19 main protease (Mpro)

The present work elicits a novel approach to combating COVID-19 by synthesizing a series of azo-anchored 3,4-dihydroimidazo[4,5-b]indole derivatives. The envisaged methodology involves the L-proline-catalyzed condensation of para-amino-functionalized azo benzene, indoline-2,3-dione, and ammonium acetate precursors with pertinent aryl aldehyde derivatives under ultrasonic conditions. The structures of synthesized compounds were corroborated through FT-IR, 1H NMR, 13C NMR, and mass analysis data. Molecular docking studies assessed the inhibitory potential of these compounds against the main protease (Mpro) of SARS-CoV-2. Remarkably, in silico investigations revealed significant inhibitory action surpassing standard drugs such as Remdesivir, Paxlovid, Molnupiravir, Chloroquine, Hydroxychloroquine (HCQ), and (N3), an irreversible Michael acceptor inhibitor. Furthermore, the highly active compound was also screened for cytotoxicity activity against HEK-293 cells and exhibited minimal toxicity across a range of concentrations, affirming its favorable safety profile and potential suitability. The pharmacokinetic properties (ADME) of the synthesized compounds have also been deliberated. This study paves the way for in vitro and in vivo testing of these scaffolds in the ongoing battle against SARS-CoV-2.

Synthesis of Sulfur-Containing Trisubstituted Imidazoles by One-Pot, Multicomponent Reaction via Electron Donor-Acceptor Complex Photoactivation

Rapid and efficient construction of multifunctionalized skeletons through a one-pot multicompound domino reaction has been recognized as a simple and practical strategy. Herein, a visible-light-enabled three-component reaction of isothiocyanates, isocyanides, and thianthrenium salt-functionalized arenes is presented, which affords a facile approach to sulfur-containing trisubstituted imidazoles in good yields with a broad substrate scope and excellent functional group tolerance. The byproduct thianthrene is recovered in quantity, thereby ultimately reducing the production of chemical waste. The developed methodology has potential value for the discovery and development of thioimidazole-based drugs.

Hydrazyl hydroxycoumarins as new potential conquerors towards Pseudomonas aeruginosa

A class of unique hydrazyl hydroxycoumarins (HHs) as novel structural scaffold was developed to combat dreadful bacterial infections. Some HHs could effectively suppress bacterial growth at low concentrations, especially, pyridyl HH 7 exhibited a good inhibition against Pseudomonas aeruginosa 27853 with a low MIC value of 0.5 μg/mL, which was 8-fold more active than norfloxacin. Furthermore, pyridyl HH 7 with low hemolytic activity and low cytotoxicity towards NCM460 cells showed much lower trend to induce the drug-resistant development than norfloxacin. Preliminarily mechanism exploration indicated that pyridyl HH 7 could eradicate the integrity of bacterial membrane, result in the leakage of intracellular proteins, and interact with bacterial DNA gyrase via non-covalent binding, and ADME analysis manifested that compound 7 gave good pharmacokinetic properties. These results suggested that the newly developed hydrazyl hydroxycoumarins as potential multitargeting antibacterial agents should be worthy of further investigation for combating bacterial infection.

Discovery of indolylacryloyl-derived oxacins as novel potential broad-spectrum antibacterial candidates

The emergence of serious bacterial resistance towards clinical oxacins poses a considerable threat to global public health, necessitating the development of novel structural antibacterial agents. Seven types of novel indolylacryloyl-derived oxacins (IDOs) were designed and synthesized for the first time from commercial 3,4-difluoroaniline via an eight-step procedure. The synthesized compounds were characterized by modern spectroscopic techniques. All target molecules were evaluated for antimicrobial activities. Most of the prepared IDOs showed a broad antibacterial spectrum and strong activities against the tested strains, especially ethoxycarbonyl IDO 10d (0.25-0.5 μg/mL) and hydroxyethyl IDO 10e (0.25-1 μg/mL) exhibited much superior antibacterial efficacies to reference drug norfloxacin. These highly active IDOs also displayed low hemolysis, cytotoxicity and resistance, as well as rapid bactericidal capacity. Further investigations indicated that ethoxycarbonyl IDO 10d and hydroxyethyl IDO 10e could effectively reduce the exopolysaccharide content and eradicate the formed biofilm, which might delay the development of drug resistance. Preliminary exploration of the antibacterial mechanism revealed that active IDOs could not only destroy membrane integrity, resulting in changes in membrane permeability, but also promote the accumulation of reactive oxygen species, leading to the production of malondialdehyde and decreased bacterial metabolism. Moreover, they exhibited the capability to bind with DNA and DNA gyrase, forming supramolecular complexes through various noncovalent interactions, thereby inhibiting DNA replication and causing bacterial death. All the above results suggested that the newly developed indolylacryloyl-derived oxacins should hold great promise as potential multitargeting broad-spectrum antibacterial candidates to overcome drug resistance.

Electron impact partial ionization cross sections: R-carvone, 2-butanol, imidazole, and 2-nitroimidazole

We calculate electron impact partial and total ionization cross sections of R-carvone (C10H14O), 2-butanol (C4H10O), imidazole (C3H4N2), and 2-nitroimidazole (C3H3N3O2). We have used the Binary Encounter Bethe (BEB) model to obtain total electron impact ionization cross sections (TICSs). The modified BEB method in combination with mass spectrum data of the molecules is used to calculate the partial ionization cross section (PICS) of the cationic fragments dissociating from the parent molecule. Our PICS data for R-carvone and 2-butanol are in good agreement with the experimental data for all the cation fragments along with the TICS data. For imidazole and 2-nitroimidazole, the estimates of the PICS are reported for the first time in the present study. We have found that both the modified BEB method and the mass spectrum dependence method work effectively to estimate PICS if we have information about the appearance energies and relative abundance data of the target under investigation.

Interference in Macrophage Balance (M1/M2): The Mechanism of Action Responsible for the Anti-Inflammatory Effect of a Fluorophenyl-Substituted Imidazole

Traditionally, the treatment of inflammatory conditions has focused on the inhibition of inflammatory mediator production; however, many conditions are refractory to this classical approach. Recently, an alternative has been presented by researchers to solve this problem: The immunomodulation of cells closely related to inflammation. Hence, macrophages, a critical key in both innate and acquired immunity, have been presented as an alternative target for the development of new medicines. In this work, we tested the fluorophenyl-imidazole for its anti-inflammatory activity and possible immunomodulatory effect on RAW 264.7 macrophages. We also evaluated the anti-inflammatory effect of the compound, and the macrophage repolarization to M2 was confirmed by the ability of the compound to reduce the M1 markers TNF-α, IL-6, MCP-1, IL-12p70, IFN-γ, and TLR4, the high levels of p65 phosphorylated, iNOS and COX-2 mRNA expression, and the fact that the compound was not able to induce the production of M1 markers when used in macrophages without lipopolysaccharide (LPS) stimulation. Moreover, fluorophenyl-imidazole had the ability to increase the M2 markers IL-4, IL-13, CD206, apoptosis and phagocytosis levels, arginase-1, and FIZZ-1 mRNA expression before LPS stimulation. Similarly, it was also able to induce the production of these same M2 markers in macrophages without being induced with LPS. These results reinforce the affirmation that the fluorophenyl-imidazole has an important anti-inflammatory effect and demonstrates that this effect is due to immunomodulatory activity, having the ability to trigger a repolarization of macrophages from M1 to M2a. These facts suggest that this molecule could be used as an alternative scaffold for the development of a new medicine to treat inflammatory conditions, where the anti-inflammatory and proregenerative properties of M2a macrophages are desired.

Discovery of Unique Bis-Substituted Aromatic Amide Derivatives as Novel Highly Potent Antibiotics for Combating Methicillin-Resistant Staphylococcus aureus (MRSA)

Due to the increasing antibiotic resistance, developing novel antimicrobials to fight infections caused by resistant bacteria is imperative. Herein, a series of novel bis-substituted aromatic amides were designed and synthesized through modifying the hit compound 1, and their antimicrobial activities were evaluated. Among them, compound 4t, as the most potent lead, exhibited excellent antimicrobial activities against Gram-positive bacteria, including clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates, while keeping weak hemolytic and mammalian cytotoxic activities. Furthermore, compound 4t displayed rapid bactericidal capabilities, low tendency to produce resistance, and favorable capacities to destroy bacterial biofilms. Further explorations indicated that compound 4t induces bacterial death by binding to cardiolipin (CL) on the bacterial membrane, disrupting the cell membrane, and facilitating the accumulation of reactive oxygen species (ROS). Additionally, compound 4t showed remarkable anti-MRSA activity in vivo, demonstrating compound 4t could be developed as a potential candidate to combat MRSA infections.

Phototoxicity of cyclometallated Ir(III) complexes bearing a thio-bis-benzimidazole ligand, and its monodentate analogue, as potential PDT photosensitisers in cancer cell killing

Two novel cyclometallated iridium(III) complexes have been prepared with one bidentate or two monodentate imidazole-based ligands, 1 and 2, respectively. The complexes showed intense emission with long lifetimes of the excited state. Femtosecond transient absorption experiments established the nature of the lowest excited state as 3IL state. Singlet oxygen generation with good yields (40% for 1 and 82% for 2) was established by detecting 1O2 directly, through its emission at 1270 nm. Photostability studies were also performed to assess the viability of the complexes as photosensitizers (PS) for photodynamic therapy (PDT). Complex 1 was selected as a good candidate to investigate light-activated killing of cells, whilst complex 2 was found to be toxic in the dark and unstable under light. Complex 1 demonstrated high phototoxicity indexes (PI) in the visible region, PI > 250 after irradiation at 405 nm and PI > 150 at 455 nm, in EJ bladder cancer cells.

A Facile Ugi/Ullmann Cascade Reaction to Access Fused Indazolo-Quinoxaline Derivatives with Potent Anticancer Activity

A facile methodology for the construction of a complex heterocycle indazolo-fused quinoxalinone has been developed via an Ugi four-component reaction (U-4CR) followed by an intramolecular Ullmann reaction. The expeditious process features an operationally simple approach, time efficiency, and a broad substrate scope. Biological activity was evaluated and demonstrated that compound 6e inhibits human colon cancer cell HCT116 proliferation with an IC50 of 2.1 μM, suggesting potential applications for developing a drug lead in medicinal chemistry.

Synthesis of 5-(trifluoroacetyl)imidazoles from Bromoenones and Benzimidamides via Aza-Michael Initiated Ring Closure Reaction

INTRODUCTION

A simple method for the preparation of 5-(trifluoroacetyl)imidazoles was elaborated.

METHODS

The reaction of trifluoromethyl(α-bromoalkenyl)ketones with benzimidamides was employed to afford the target heterocycles in good yields.

RESULTS

The assembly of imidazole core proceeds via aza-Michael adduct formation followed by intramolecular nucleophilic substitution and spontaneous aromatization as an oxidation sequence.

CONCLUSION

The yields of target imidazoles can be improved by the use of soft oxidizing agents.

Evaluation of calf thymus DNA binding of newly synthesize five 9 O Imidazolyl alkyl berberine derivative: A comparative multi-spectroscopic and calorimetric study

DNA binding with small molecule plays an important role in the designing of various anticancer drugs with greater efficacy. The five 9-O-imidazolyl alkyl berberine derivatives (BI) of different chain length has been synthesized and fully characterized. The binding study of calf thymus DNA with these newly synthesized berberine derivative was performed using various biophysical techniques. The binding affinity of BI to calf thymus DNA increased with increasing the chain length. The binding constant value obtained from UV-Vis spectral analysis was 1.84x105for BI1, 2.01x105for BI2, 1.51 × 106 for BI3, 3.66 × 106 for BI4, 6.68 × 106. Partial intercalative binding with strong stabilization of the DNA helix was revealed from circular dichroism spectral study and viscosity measurement. From the ITC experiment it was revealed that the bindings of BI1, BI2, BI3, BI4 and BI5 to calf thymus DNA were favoured by a large positive favourable entropy and negative enthalpy change and the highest spontaneity found for BI5. With the increase in chain length the binding was driven by a stronger entropy term with a higher binding constant indicates involvement of hydrophobic force for all these interaction. High binding affinities of calf thymus DNA with berberine-imidazole derivatives might be helpful for new drug design.

Benzopyrone-mediated quinolones as potential multitargeting antibacterial agents

A new type of benzopyrone-mediated quinolones (BMQs) was rationally designed and efficiently synthesized as novel potential antibacterial molecules to overcome the global increasingly serious drug resistance. Some synthesized BMQs effectively suppressed the growth of the tested strains, outperforming clinical drugs. Notably, ethylidene-derived BMQ 17a exhibited superior antibacterial potential with low MICs of 0.5-2 μg/mL to clinical drugs norfloxacin, it not only displayed rapid bactericidal performance and inhibited bacterial biofilm formation, but also showed low toxicity toward human red blood cells and normal MDA-kb2 cells. Mechanistic investigation demonstrated that BMQ 17a could effectually induce bacterial metabolic disorders and promote the enhancement of reactive oxygen species to disrupt the bacterial antioxidant defense system. It was found that the active molecule BMQ 17a could not only form supramolecular complex with lactate dehydrogenase, which disturbed the biological functions, but also effectively embed into calf thymus DNA, thus affecting the normal function of DNA and achieving cell death. This work would provide an insight into developing new molecules to reduce drug resistance and expand antibacterial spectrum.

New imidazole-2-ones and their 2-thione analogues as anticancer agents and CAIX inhibitors: Synthesis, in silico ADME and molecular modeling studies

The present study involves the synthesis of a series of new imidazole-2-ones derivatives and their 2-thione analogs using conventional heating and the environmentally friendly benign technique, the microwave technique. Structure of the compounds was well elucidated by considering the data of both elemental and spectral analyses. The obtained data and theoretical values of the synthesized molecules correlated with the proposed molecular structure. Moreover, all the synthesized compounds were evaluated in vitro for antitumor activity against HCT-116 and HeP2 human cancer cell panels and assessed as selective carbonic anhydrase IX isozyme (CA9/CAIX) inhibitors, thereby providing useful preliminary evidence for drug development. In addition, computational techniques were used to investigate the molecular and electronic characteristics of the investigated organic compounds. The 4b compound exhibited the best quantum chemistry features, as the highest occupied molecular orbital, softness, energy gap, and dipole moment, indicating the highest biological activity. This was supported by the experimental findings. Moreover, the in silico evaluation of drug candidates was also investigated. Thereafter, the anticancer activity of the most reactive candidate was studied via molecular docking to determine the types of interactions between this molecule and CAIX. According to the docking experiments, the 4b molecule generates five hydrogen bond interactions with active amino acid residues, Gln 92, Gln 67, and Thr 200.

Identification of unique indolylcyanoethylenyl sulfonylanilines as novel structural scaffolds of potential antibacterial agents

The increasing incidence of antibiotic resistance has forced the development of unique antimicrobials with novel multitargeting mechanisms to combat infectious diseases caused by multidrug-resistant pathogens. Structurally unique indolylcyanoethylenyl sulfonylanilines (ISs) were exploited as novel promising antibacterial agents to confront stubborn drug resistance. Some prepared ISs possessed favorable bacteriostatic action towards the tested bacteria. Especially, hydroxyethyl IS 14a exerted 8-fold more potent inhibitory efficacy against multidrug-resistant A. baumannii and E. coli 25922 with the low MIC of 0.5 μg/mL than norfloxacin, and showed low cell toxicity and rapid bactericidal property. Moreover, this compound also possessed obvious effect of eradicating bacterial biofilm, which could effectually relieve the development of drug resistance. A preliminary assessment of the antibacterial mechanism indicated that compound 14a could disintegrate membrane integrity leading to the leakage of intracellular protein, inactivation of lactate dehydrogenase and metabolism inhibition. Hydroxyethyl IS 14a mediated the accumulation of excess reactive oxygen species, which further contributed to reducing glutathione, resulting in oxidative damage to bacteria. Furthermore, IS 14a could intercalate into DNA to hinder the biological function of DNA. Quantum chemical study disclosed that IS 14a with the lowest energy gap was conducive to displaying high bioactivity. These findings demonstrated that hydroxyethyl IS 14a as a prospective antimicrobial candidate for combating A. baumannii and E. coli 25922 would be a promising starting point.

Design, Synthesis, and Anti-Breast Cancer Potential of Imidazole-Pyridine Hybrid Molecules In Vitro and Ehrlich Ascites Carcinoma Growth Inhibitory Activity Assessment In Vivo

Breast cancer remains a challenging medical issue and is a high priority for biomedical research despite significant advancements in cancer research and therapy. The current study aims to determine the anticancer activity of a group of imidazole-pyridine-based scaffolds against a variety of breast cancer cell lines differing in their receptor expression (estrogen receptor (ER), progesterone receptor (PR), and HER-2). A series of 10 molecules (coded 5a-5j) were synthesized through multicomponent and alkylation reactions. FTIR, MS, 1H, and 13C NMR spectral analyses confirmed the structures and purity of the synthesized molecules. Subsequently, these molecules were tested for their ability to inhibit the viability of cell lines representing carcinoma of the breast, viz., MDA-MB-468 (ER-, PR-, and HER-), BT-474 (ER+, PR+, and HER+), T-47D (ER+, PR+, and HER-), and MCF-7 (ER+, PR+, and HER-) in vitro. Among these 10 molecules, 5a, 5c, 5d, and 5e exhibited better potency, as evidenced by IC50 < 50 μM at 24 h of treatment against BT-474 and MDA-MB-468 cell lines. However, except for 5d, the IC50 value is much higher than 50 μM when tested against T47D and MCF-7 cell lines at 24h. Extended treatment for 48 h reduced the effect of these molecules, as an increase in IC50 was observed. In mice, intraperitoneal administration of 5e retarded the Ehrlich ascites carcinoma (EAC) growth without causing any organ toxicity at the doses tested. In summary, we report the synthesis scheme and key structural requirements for a new series of imidazole-pyridine molecules for in vitro inhibition of the feasibility of breast cancer cells and in vivo inhibition of EAC tumors.

The Role of Five-Membered Heterocycles in the Molecular Structure of Antibacterial Drugs Used in Therapy

Five-membered heterocycles are essential structural components in various antibacterial drugs; the physicochemical properties of a five-membered heterocycle can play a crucial role in determining the biological activity of an antibacterial drug. These properties can affect the drug's activity spectrum, potency, and pharmacokinetic and toxicological properties. Using scientific databases, we identified and discussed the antibacterials used in therapy, containing five-membered heterocycles in their molecular structure. The identified five-membered heterocycles used in antibacterial design contain one to four heteroatoms (nitrogen, oxygen, and sulfur). Antibacterials containing five-membered heterocycles were discussed, highlighting the biological properties imprinted by the targeted heterocycle. In some antibacterials, heterocycles with five atoms are pharmacophores responsible for their specific antibacterial activity. As pharmacophores, these heterocycles help design new medicinal molecules, improving their potency and selectivity and comprehending the structure-activity relationship of antibiotics. Unfortunately, particular heterocycles can also affect the drug's potential toxicity. The review extensively presents the most successful five-atom heterocycles used to design antibacterial essential medicines. Understanding and optimizing the intrinsic characteristics of a five-membered heterocycle can help the development of antibacterial drugs with improved activity, pharmacokinetic profile, and safety.

Direct Decarboxylative C-2 Alkylation of Azoles through Minisci-Type Coupling

This note discusses the application of a Minisci-type reaction for the direct alkylation of azoles with carboxylic acids as radical precursors. Different reaction conditions were investigated to achieve high yield of the desired products, focusing on acid strength and solvent screening. Moreover, the reactivity of imidazoles with various carboxylic acids was investigated, showing good yield for most cases. The study reveals the potential of this approach for late-stage functionalization in drug discovery.

One-pot synthesis, spectral characterization, biological evaluation, molecular docking studies and in silico ADME/Tox profiling of new 2,4,5 triaryl imidazole derivatives as anti tubercular agents

BACKGROUND

Tuberculosis still looms large on the global epidemiological radar and warrants continuous effort in the direction of developing new anti TB drugs to battle evolving resistance mechanisms of the causative agent Mycobacterium tuberculosis.

METHODS

In the present paper, synthesis of n has been attempted. All the synthesized compounds were characterized by 1H-NMR, 13C-NMR, IR and Mass spectroscopy. Anti TB profile of the synthesized compounds were tested by MABA assay employing M.tb H37Rv strain.

RESULTS

Two compounds namely N-(2-acetoxy)-N-methyl-4-(4,5-diphenyl-1H-imidazole-2-yl) benzenamine and 2-(N-(4-(4,5-bis(4-methoxyphenyl)-1H-imidazole-2-yl)phenyl)-N-methylamino) ethanol exhibited impressive anti TB inhibitory potential with an MIC of 3.125 μg/mL. To visualize the binding interactions of the active compounds molecular docking studies were carried out on putative target M. tuberculosis Glutamine synthetase (MtGS) in complex with a trisubstituted imidazole. To ascertain their drug likeliness and safety profile in silico ADME/T prediction was performed on all the synthesized compounds.

CONCLUSION

Three compounds 1a, 2g and 2c exhibited good inhibitory potency against M.tb H37Rv and all the synthesized compounds also show promising antifungal activity.