Search Results (42)

The clinical advancement of the ruthenium complex [bis(4,4′-dimethyl-2,2′-bipyridin){2-(2,2′:5′,2″-terthiophen-5-yl)imidazo[4,5-f][1,10]phenanthroline}ruthenium]dichloride (TLD-1433) has provided a breath of fresh air to the bioinorganic chemistry of metal-based complexes, especially those developed around Ru(II). The success of TLD-1433 resides in its dual metal–ligand photodynamic therapy mechanism, which allows for the treatment of hypoxic cancer. The presence of α-terthiophene at the periphery of the polypyridyl complex positively modified the photophysical property of the ruthenium complex; however, it is unclear if it possesses other favorable attributes. Considering the tremendous structural and photophysical diversity of terthiophene derivatives (14 isomers), as well as α-terthiophene’s recognized nematocidal activity, the following questions can be asked: What is the main role of α-terthiophene in TLD-1433? Is it to act as a pharmacophoric element, a photo-physical modulator, or a simple structural motif? Can a terthiophene motif be beneficial for other metal-based or organic drugs? Full article

The continuous search for new chemical structures more active and less toxic than those currently in practice is justified on the basis of the use of proven pharmacophoric building blocks (benzimidazole heterocycle, sulfonyl group and amidoxime framework in our case). The aim of the work was to synthesize new O-alkylsulfonyl-β-(benzimidazol-1-yl)propioamidoximes and to test them for in vitro biological activities to identify potentially effective agents. Novel O-alkylsulfonylamidoximes were synthesized in hydrochloride and base forms by the reaction of β-(benzimidazol-1-yl)propioamidoxime with alkylsulfonyl chlorides AlkSO₂Cl (Alk = CH₃, n-C₃H₇, i-C₃H₇, n-C₄H₉) in a mixture of water:acetone in hydrochloride and base forms. Hydrochlorides and bases of the O-alkylsulfonyl-β-(benzimidazol-1-yl)propioamidoximes were obtained in moderate to high yields. The structures of the synthesized compounds were established by physicochemical and spectral (elemental analysis, FT-IR, NMR and X-ray diffraction) methods. The obtained derivatives were tested for antimicrobial, antifungal and antidiabetic activity. Biological screening found effective samples of amidoximes with antimicrobial and antifungal activities that were near or exceeded the activity of the reference drugs gentamicin and nystatin; in addition, two samples with antidiabetic activity higher than acarbose were found. The results of the present study open new possibilities for the novel β-aminopropioamidoxime class as active antimicrobial and antifungal agents, as well as antidiabetic ones. Full article

Background/Objectives: Fraxetin (7,8-dihydroxy-6-methoxycoumarin), a coumarin constituent of Cortex Fraxini (Qinpi) used in traditional Chinese medicine, is metabolised mainly by UGT1A9, but its potential to inhibit UGT enzymes and cause herb–drug interactions (HDIs) is largely unstudied. Methods: Fraxetin and four related coumarins were screened against 11 recombinant human UGTs; isoforms inhibited ≥80% underwent full kinetic analysis with 4-methylumbelliferone as probe. Binding was examined by molecular docking on AlphaFold structures with PLIP, triplicate 100 ns molecular dynamics, and MM/GBSA and MM/PBSA free-energy calculations, and interaction risk by FDA 2020 in vitro–in vivo extrapolation (IVIVE). Results: Fraxetin alone inhibited both UGT1A1 and UGT1A9 by >80% and was characterised in detail, acting as a mainly competitive mixed-type inhibitor (UGT1A1 IC₅₀ 15.99 μM, K_i 8.32 μM; UGT1A9 IC₅₀ 8.44 μM, K_i 5.90 μM). A structure–activity comparison identified a dual-element pharmacophore comprising the C-6 methoxy group and the 7,8-dihydroxycoumarin aglycone. MM/GBSA favoured UGT1A9 over UGT1A1 (ΔΔG = −4.06 kcal/mol, p = 0.005), concordant with the kinetic ranking. IVIVE predicted a borderline systemic signal (R₁ > 1.02) but an intestinal R_1,gut approximately five- to seven-fold above the high-risk threshold of 11 after capping the luminal concentration at fraxetin aqueous solubility. Conclusions: This is the first characterisation of fraxetin as a moderate-potency inhibitor of UGT1A1 and UGT1A9 and points to a previously under-recognised herb–drug interaction risk concentrated in the intestinal lumen rather than systemically; the finding constitutes an interaction signal requiring clinical confirmation rather than an established risk. Full article

This study details the synthesis, characterization, molecular docking and preliminary biological evaluation of a new heterocyclic compound, 2-((4-morpholino-1,2,5-thiadiazol-3-yl)oxy)benzaldehyde. This molecule was designed using an artificial intelligence (AI)-based molecular generative model. It was synthesized through a nucleophilic substitution between 3-chloro-4-morpholino-1,2,5-thiadiazole and 2-hydroxybenzaldehyde. Structural elucidation was performed using ¹H NMR, ¹³C NMR, Elemental Analysis, and Single Crystal X-ray diffraction. AI-guided in silico predictions suggested promising pharmacophoric features and potential biological activity. Preliminary biological evaluation, primarily through anticancer assays, demonstrated moderate to significant activity, supporting further investigation. The findings therefore suggest that this AI-generated molecule could serve as a lead scaffold for developing drugs targeting cancer and other infectious diseases. Full article

Background/Objectives: Microtubule-targeting agents remain foundational components of anticancer chemotherapy, yet their clinical utility is constrained by resistance and toxicity. Methods: Here, we present a theoretical exploration of a plausible “dual” binding pocket that spans the α-tubulin pironetin site and the inter-subunit todalam site. Eight virtual chimeric ligands, each merging key pharmacophoric elements of pironetin and todalam, were constructed and covalently docked to Cys316 of α-tubulin. Results: Covalent docking followed by 200 ns all-atom molecular dynamics simulations revealed that two derivatives (compounds 4 and 8) stably occupy the merged cavity, simultaneously anchoring in the pironetin region via Michael addition and in the todalam region via π-stacking and hydrogen bonding. These hybrids preserved the critical hydrogen-bonding networks of both parent ligands and exhibited low ligand RMSD values (~1.5 Å) and compact radii of gyration throughout the simulations, indicating a tight, persistent binding. Estimated HYDE affinities of 1.5 µM for compound 4 and 17.6 µM for compound 8, calculated with SeeSAR, suggest that covalent engagement can compensate for moderate non-covalent binding scores. Conclusions: In summary, our results provide compelling grounds for developing a new class of α-tubulin inhibitors that engage the hybrid pocket, laying a foundation for the structure-guided synthesis of first-in-class dual-site compounds capable of overcoming resistance to conventional microtubule-targeting drugs. Full article

Heterocyclic systems such as 1,2,4-triazoles and piperazines play an important role in modern medicinal chemistry due to their structural diversity and broad spectrum of biological activities. In this Short Note, we report the synthesis and spectroscopic characterization of a new hybrid molecule combining both pharmacophoric fragments: 1-[4-(4-chlorophenyl)piperazin-1-yl]-2-[(4-phenyl-4H-1,2,4-triazol-3-yl)sulfanyl]ethan-1-one (compound 3). The compound was obtained in 70% yield via S-alkylation of 4-phenyl-1,2,4-triazole-3-thione with a chloroacetyl derivative of 4-chlorophenylpiperazine under alkaline conditions. The structure of 3 was confirmed by ¹H and ¹³C NMR spectroscopy, DEPT-135, 2D NMR (COSY, NOESY, HSQC, HMBC), FT-IR, and elemental analysis. These results support the utility of combining triazole and piperazine fragments in the design of new heterocyclic frameworks with potential biological relevance. Full article

One of the best-known flavonoid chrysin was coupled at position 7 with several trisubstituted phosphine derivatives with a flexible spacer, and their in vitro anticancer activities were investigated on 60 human tumor cell lines (NCI60) and on several gynecological cancer cells. The trisubstituted phosphines contained different substituents on the aromatic ring(s), e.g., methyl and methoxy groups or fluoro atoms. The phosphorus atom was substituted not only with aromatic rings but with cyclohexyl substituents. The ionic phosphonium building block is important because it allows the therapeutic agents to transfer across the cell membrane. Therefore, the pharmacophores linked to it can exert their effects in the mitochondria. Instead of the ionic phosphonium element, a neutral moiety, namely the triphenylmethyl group, was also added to the side chain, being sterically similar but without a charge and phosphorus atom. Most of the hybrids exhibited low micromolar growth inhibition (GI₅₀) values against the majority of the tested cell lines. Notably, conjugate 3f stood out, demonstrating nanomolar antitumor activity against the K-562 leukemia cell line (GI₅₀ = 34 nM). One selected compound (3i) with promising cancer selectivity elicited cell cycle disturbances and inhibited the migration of breast cancer. The tumor-selectivity of 3a and 3f was assessed based on their effects on non-tumor Chinese hamster ovary (CHO) cells using the CellTiter-Glo Luminescent Cell Viability Assay. Given their estimated half-maximal inhibitory concentration (IC₅₀) values on non-tumor CHO cells (2.65 µM and 1.15 µM, respectively), these conjugates demonstrate promising selectivity toward several cancer cell lines. The excellent results obtained may serve as good starting points for further optimization and the design of even more effective flavonoid- and/or phosphonium-based drugs. Full article

Risdiplam is the first approved small-molecule therapy for spinal muscular atrophy (SMA), a severe, progressive neuromuscular disorder. In addition to its clinical significance, risdiplam is of a great interest for organic and medicinal chemistry due to its complex molecular architecture. Its structure incorporates three highly substituted heterocyclic fragments—imidazo[1,2-b]pyridazine, pyrido[1,2-a]pyrimidin-4-one, and 4,7-diazaspiro[2.5]octane—that serve as both versatile synthetic building blocks and critical pharmacophoric elements for drug design and discovery. The increasing scientific interest in risdiplam has led to numerous publications and patent applications that describe alternative synthetic methodologies. Recently, our group has also developed and introduced efficient, scalable manufacturing routes for the preparation of the target substance and the key intermediates of its synthesis. This mini-review systematically analyzes a plethora of risdiplam assembly strategies and synthetic approaches, covering developments from 2013 to the present. Full article

This study focuses on exploring potential inhibitors of the Marburg virus interferon inhibitory domain protein (MARV-VP35), which is responsible for immune evasion and immunosuppression during viral manifestation. A combination of in silico techniques was applied, including structure-based pharmacophore virtual screening, molecular docking, absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis, molecular dynamics (MD), and molecular stability assessment of the identified hits. The docking scores of the 14 selected ligands ranged between −6.88 kcal/mol and −5.28 kcal/mol, the latter being comparable to the control ligand. ADMET and drug likeness evaluation identified Mol_01 and Mol_09 as the most promising candidates, both demonstrating good predicted antiviral activity against viral targets. Density functional theory (DFT) calculations, along with relevant quantum chemical descriptors, correlated well with the docking score hierarchy, and molecular electrostatic potential (MEP) mapping confirmed favorable electronic distributions supporting the docking orientation. Molecular dynamics simulations further validated complex stability, with consistent root mean square deviation (RMSD), root mean square fluctuation (RMSF), and secondary structure element (SSE) profiles. These findings support Mol_01 and Mol_09 as viable candidates for experimental validation. Full article

The hydroxylated perhydroquinoxaline 14 was designed by conformational restriction of the prototypical κ receptor agonist U-50,488 and the introduction of an additional polar group. The synthesis of 14 comprised ten reaction steps starting from diethyl 3-hydroxyglutarate (4). The first key step was the diastereoselective establishment of the tetrasubstituted cyclohexane 7 by the reaction of dialdehyde 6 with benzylamine and nitromethane. The piperazine ring was annulated by the reaction of silyloxy-substituted cyclohexanetriamine 8 with dimethyl oxalate. The pharmacophoric structural elements characteristic for κ receptor agonists were finally introduced by functional group modifications. The structure including the relative configuration of the tetrasubstituted cyclohexane derivative (2r,5s)-7a and the perhydroquinoxaline 9 was determined unequivocally by X-ray crystal structure analysis. The hydroxylated perhydroquinoxaline 14 showed moderate κ receptor affinity (K_i = 599 nM) and high selectivity over μ, δ, σ₁, and σ₂ receptors. An ionic interaction between the protonated pyrrolidine of 14 and D138 of κ receptor anchors 14 in the κ receptor binding pocket. Full article

A convenient synthesis of a novel fluoroquinolone precursor, methyl 6,7-difluoro-2-[(4-fluorobenzyl)sulfanyl]-4-hydroxyquinoline-3-carboxylate, at a 78% yield starting from 3,4-difluorophenyl isothiocyanate was developed. The structure of the product was established by ¹H, ¹³C, and ¹⁹F NMR spectroscopy, mass spectrometry, IR spectroscopy and confirmed by elemental analysis. The title compound, containing the pharmacophoric 4-fluorobenzyl group, will be used in the synthesis of novel fluoroquinolone derivatives. Full article

Multitarget compounds have emerged as promising drug candidates to cope with complex multifactorial diseases, like Alzheimer’s disease (AD). Most multitarget compounds are designed by linking two pharmacophores through a tether chain (linked hybrids), which results in rather large molecules that are particularly useful to hit targets with large binding cavities, but at the expense of suffering from suboptimal physicochemical/pharmacokinetic properties. Molecular size reduction by removal of superfluous structural elements while retaining the key pharmacophoric motifs may represent a compromise solution to achieve both multitargeting and favorable physicochemical/PK properties. Here, we report the stepwise structural simplification of the dihydroxyanthraquinone moiety of a rhein–huprine hybrid lead by hydroxy group removal—ring contraction—ring opening—ring removal, which has led to new analogs that retain or surpass the potency of the lead on its multiple AD targets while exhibiting more favorable drug metabolism and pharmacokinetic (DMPK) properties and safety profile. In particular, the most simplified acetophenone analog displays dual nanomolar inhibition of human acetylcholinesterase and butyrylcholinesterase (IC₅₀ = 6 nM and 13 nM, respectively), moderately potent inhibition of human BACE-1 (48% inhibition at 15 µM) and Aβ42 and tau aggregation (73% and 68% inhibition, respectively, at 10 µM), favorable in vitro brain permeation, higher aqueous solubility (18 µM) and plasma stability (100/96/86% remaining in human/mouse/rat plasma after 6 h incubation), and lower acute toxicity in a model organism (zebrafish embryos; LC₅₀ >> 100 µM) than the initial lead, thereby confirming the successful lead optimization by structural simplification. Full article

This study focuses on the synthesis and structural characterization of new compounds that integrate thiazolidine-2,4-dione, acridine moiety, and an acetamide linker, aiming to leverage the synergistic effects of these pharmacophores for enhanced therapeutic potential. The newly designed molecules were efficiently synthesized through a multi-step process and subsequently transformed into their hydrochloride salts. Comprehensive spectroscopic techniques, including nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), infrared (IR) spectroscopy, and elemental analysis, were employed to determine the molecular structures of the synthesized compounds. Biological evaluations were conducted to assess the therapeutic potential of the new compounds. The influence of these derivatives on the metabolic activity of various cancer cell lines was assessed, with IC₅₀ values determined via MTT assays. An in-depth analysis of the structure–activity relationship (SAR) revealed intriguing insights into their cytotoxic profiles. Compounds with electron-withdrawing groups generally exhibited lower IC₅₀ values, indicating higher potency. The presence of the methoxy group at the linking phenyl ring modulated both the potency and selectivity of the compounds. The variation in the acridine core at the nitrogen atom of the thiazolidine-2,4-dione core significantly affects the activity against cancer cell lines, with the acridin-9-yl substituent enhancing the compounds’ antiproliferative activity. Furthermore, compounds in their hydrochloride salt forms demonstrated better activity against cancer cell lines compared to their free base forms. Compounds 12c·2HCl (IC₅₀ = 5.4 ± 2.4 μM), 13d (IC₅₀ = 4.9 ± 2.9 μM), and 12f·2HCl (IC₅₀ = 4.98 ± 2.9 μM) demonstrated excellent activity against the HCT116 cancer cell line, and compound 7d·2HCl (IC₅₀ = 4.55 ± 0.35 μM) demonstrated excellent activity against the HeLa cancer cell line. Notably, only a few tested compounds, including 7e·2HCl (IC₅₀ = 11.00 ± 2.2 μM), 7f (IC₅₀ = 11.54 ± 2.06 μM), and 7f·2HCl (IC₅₀ = 9.82 ± 1.92 μM), showed activity against pancreatic PATU cells. This type of cancer has a very high mortality due to asymptomatic early stages, the occurrence of metastases, and frequent resistance to chemotherapy. Four derivatives, namely, 7e·2HCl, 12d·2HCl, 13c·HCl, and 13d, were tested for their interaction properties with BSA using fluorescence spectroscopic studies. The values for the quenching constant (K_sv) ranged from 9.59 × 10⁴ to 10.74 × 10⁴ M⁻¹, indicating a good affinity to the BSA protein. Full article

Proteases represent common targets in combating infectious diseases, including COVID-19. The 3-chymotrypsin-like protease (3CLpro) is a validated molecular target for COVID-19, and it is key for developing potent and selective inhibitors for inhibiting viral replication of SARS-CoV-2. In this review, we discuss structural relationships and diverse subsites of 3CLpro, shedding light on the pivotal role of dimerization and active site architecture in substrate recognition and catalysis. Our analysis of bioinformatics and other published studies motivated us to investigate a novel catalytic mechanism for the SARS-CoV-2 polyprotein cleavage by 3CLpro, centering on the triad mechanism involving His41-Cys145-Asp187 and its indispensable role in viral replication. Our hypothesis is that Asp187 may participate in modulating the pK_a of the His41, in which catalytic histidine may act as an acid and/or a base in the catalytic mechanism. Recognizing Asp187 as a crucial component in the catalytic process underscores its significance as a fundamental pharmacophoric element in drug design. Next, we provide an overview of both covalent and non-covalent inhibitors, elucidating advancements in drug development observed in preclinical and clinical trials. By highlighting various chemical classes and their pharmacokinetic profiles, our review aims to guide future research directions toward the development of highly selective inhibitors, underscore the significance of 3CLpro as a validated therapeutic target, and propel the progression of drug candidates through preclinical and clinical phases. Full article

Herein, the synthesis, structural characterization and in vitro biological evaluation of a novel Cu(II) complex with the 2-(4-aminophenyl)benzothiazole pharmacophore conjugated with the (2-pyridinyl)methylamino chelating moiety is reported for the first time. A full characterization of the Cu(II) complex was conducted by X-ray crystallography, EPR, IR, elemental and MS analysis, and its binding to CT-DNA was investigated by UV-vis spectroscopy, ethidium bromide competition studies, circular dichroism, viscometry and thermal denaturation. The data clearly indicate that the Cu(II) complex interacts with CT-DNA via intercalation, registering a difference compared to previously reported Pt(II) and Pd(II) analogues. To evaluate the anticancer activity of the complex, a series of in vitro experiments against breast, glioblastoma, prostate and lung cancer cell lines along with healthy fibroblasts were implemented. Cytotoxicity, cellular uptake, intracellular ROS production, cell cycle and apoptosis analysis revealed an increased anticancer activity towards breast cancer cells that is accompanied by an induction in intracellular ROS levels and a significant G2/M arrest followed by apoptosis. Full article