Search Results (490)

In this study, a new series of (E)-4-((2-(2-(4-amino-3-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)acetyl)hydrazono)methyl)phenyl 4-halogenobenzenesulfonates (3a–3d), where 3a = F, 3b = Cl, 3c = Br, and 3d = I, were successfully synthesized via a straightforward synthetic route. The structures of the obtained compounds were fully characterized and confirmed by spectroscopic techniques, including FT-IR, ¹H NMR, and ¹³C NMR, as well as LC-MS/MS analysis. 1,2,4-triazole-based hydrazone derivatives (3a–3d) were investigated using IR and NMR spectroscopy and DFT calculations. Intermolecular interactions, HOMO-LUMO, dipole moment, polarization, first-order hyperpolarizability, and molecular electrostatic potential studies on the molecules were examined. The HOMO and LUMO energy gap study supports the charge transfer probability in the molecules. These were conducted to investigate the reactivity and stability of heterocyclic molecules in bioactivity analysis. Electron density mapping within the molecular electrostatic potential plot and electrostatic potential representation within the iso-surface plot evaluated the concept of charge distribution in the molecule as nucleophilic reactions and electrophilic regions. The predicted nonlinear optical (NLO) properties of the molecules are much greater than those of urea. The results obtained from these investigations collectively provide evidence that the molecules possess nonlinear optical applications. Novel triazole–hydrazone-functionalized aryl sulfonate derivatives (3a–3d) were evaluated for their anticancer potential against a panel of brain and non-brain cancer cell lines. Compound 3b exhibited the most favorable overall biological profile, displaying potent activity against SH-SY5Y neuroblastoma (GI = 7.59 μM) and U87MG glioblastoma cells (GI = 13.85 μM), together with the lowest toxicity toward normal FL fibroblasts (GI = 62.02 μM). Compounds 3c and 3d demonstrated remarkable potency against IDHmut-U87 glioma cells (GI = 3.87 and 3.27 μM, respectively), although their selectivity toward cancer cells was limited. DNA degradation studies revealed substantial fragmentation, particularly in C6 and SH-SY5Y cells, while migration assays indicated reduced cellular motility. Molecular docking studies identified compound 3b as the strongest PI3Kα binder, supporting a possible. In addition, the antimicrobial activities of compounds 3a–3d were evaluated against selected Gram-positive and Gram-negative bacteria as well as Candida species using the broth microdilution method. The compounds exhibited measurable antimicrobial effects with MIC values ranging from 156 to 625 µg/mL, showing moderate growth inhibition against the tested microorganisms. Although the observed activity was lower than that of the reference antimicrobial agents, the results indicate that these triazole–hydrazone derivatives possess a detectable level of antimicrobial activity and provide a basis for further structural optimization. Collectively, the results suggest that compound 3b represents the most promising lead structure due to its balanced combination of potency, selectivity, and predicted target engagement. Molecular docking was performed to evaluate the binding potential of newly synthesized triazole derivatives (3a–3d) against PI3Kα. The docking protocol was validated by re-docking alpelisib, yielding an RMSD of 0.64 Å. Among the tested compounds, 3b showed the most favorable binding energy (−9.94 kcal/mol) and estimated Ki value (52.13 nM), consistent with its superior in vitro activity. Its interactions with key PI3Kα residues, including Val851, Ser854, Met922, and Asp933, support a stable binding mode within the ATP-binding pocket. In silico ADME and toxicity analyses suggested acceptable drug-likeness characteristics, absence of major hepatotoxic, mutagenic, and carcinogenic liabilities, and moderate predicted acute toxicity profiles. These findings suggest that 3b is the most promising derivative for further validation. Full article

Background/Objectives: Leishmaniases are a group of neglected tropical diseases that have been overlooked, and new treatments are needed. This is because the parasites that cause it, from the Leishmania genus, have become drug-resistant, and current medications can be toxic. In this regard, arylidenehydrazinyl thiazoles emerge as a potential scaffold for creating new, effective drug candidates to combat this disease. Methods: Here, we report the synthesis of a series of arylidenehydrazinyl thiazole carboxylates (3a–m, 13 examples, 66–78%) using a simple cost-effective strategy via cyclization of aryl-substituted thiosemicarbazones and ethyl-2-chloro-3-oxobutanoate in an equimolar mixture. These compounds were investigated for their promising bioactive properties. Results: All compounds were fully characterized using spectroscopic techniques (¹H-, ¹³C-NMR, FTIR spectroscopy, and HRMS) to confirm their purity and identity. These arylidenehydrazinyl thiazole carboxylates have been tested for their cytotoxicity against promastigote and intracellular amastigote forms of Leishmania amazonensis (IFLA/BR/1967/PH8) and the NIH/3T3 mouse fibroblast cell lines and their potential interaction with Leishmania trypanothione synthetase was explored through in silico molecular docking studies. Conclusions: The compounds showed little or no cytotoxicity against NIH/3T3 fibroblasts, compounds 3a, 3d and 3m showed low cytotoxicity to promastigote forms, but compounds 3b, 3c, 3h and 3m showed activity against amastigotes (IC₅₀ = 15.92 µM for 3m) at the tested concentrations. In silico molecular docking studies have been deployed to investigate the structural dynamics and the stability of the complex. These findings suggested that the newly developed compounds represent promising preliminary hits for further optimization toward the treatment of diseases associated with Leishmania parasites. Full article

A new three-step strategy for the preparation of 1,2-disubstituted 1H-benzo[d]imidazoles has been developed. The approach involved (1) S_NAr addition-elimination of alkyl- or arylamines to 1-fluoro-2-nitrobenzene to give N-alkyl- or N-aryl-2-nitroanilines, (2) acylation of these adducts with acid chlorides to afford N-alkyl- or N-aryl-N-(2-nitrophenyl) amides, and (3) reduction of the aromatic nitro with iron in acetic acid at 95–100 °C, followed by closure of the resulting amine on the amide carbonyl to produce 1,2-disubstituted benzimidazoles in high yields. The sequence gave the benzimidazole products in NMR-pure form with only one purification after Step 2. Thirty-seven derivatives were prepared, providing a broad selection of 1,2-disubstituted benzimidazoles. Interestingly, the reaction of the aniline nitrogen derived from the reduction of the nitro group afforded the final product by addition to the acyl carbonyl, followed by dehydrative aromatization with no competing rearrangement, acyl transfer, or side products. Full article

In this report, we describe the synthesis of two new celastrol derivatives featuring aryl-substituted 1,2,3-triazole fragments attached to the celastrol scaffold via an ester linkage. The target compounds, incorporating 4-methoxyphenyl and p-tert-butylphenyl groups, were characterized by ¹H and ¹³C NMR spectroscopy, FTIR, UV-Vis, HRMS, melting point determination, and specific rotation measurements. Full article

Aryl halides are important intermediates for chemical synthesis. However, the negative reduction potential up to −2.7 V (vs. SCE) makes photoredox conversion of aryl halides by reductive dehalogenation to aryl radicals for chemical transformations difficult. Inspired by the outstanding photophysical properties of deazaflavin and triphenylamine, as well as results of theoretical calculations, we attached the diphenylamino group to C8 of deazaflavin, and the resulting compounds look fabricated by “fusing” deazaflavin and triphenylamine (TPA) together by sharing the benzene ring. We also introduced alkyl and aryl moieties to C5 and afforded a series of deazaflavin derivatives (dFLs), namely 10-butyl-8-(diphenylamino)-3,5-dimethylpyrimido[4,5b]quinoline-2,4(3H,10H)-dione (TPAdFlMe), 10-butyl-8-(diphenylamino)-3-methyl-5-(trifluoromethyl)pyrimido[4,5-b]quinoline-2,4(3H,10H)-dione(TPAdFlTF) and 10-butyl-8-(diphenylamino)-3-methyl-5-phenylpyrimido[4,5-b]quinoline-2,4(3H,10H)-dione (TPAdFlPh), and investigated their photophysical properties and performance as sensitizers in the photodehalogenation of aryl halides. We showed that the photophysical properties are significantly improved in these dFLs. The absorption bands of dFLs are redshifted and the absorbance is more than double that of riboflavin tetraacetate (RFTA). The singlet oxygen quantum yields of TPAdFlMe, TPAdFlTF and TPAdFlPh are 0.42, 0.25 and 0.39, respectively, and the corresponding redox potentials are −1.75, −0.75 and −1.71 V vs. Ag/Ag⁺, respectively, comparable to known deazaflavin-based sensitizers. Originating from these properties, TPAdFlMe and TPAdFlPh are capable of sensitizing the full photodehalogenation of 0.038 mmol p-iodoanisole, and the yields of the photodehalogenation of 0.038 mmol p-bromoanisole are 67 and 69%, respectively. They also demonstrate exceptional performance in the photodehalogenation of halides of polycyclic aromatics with yields in the range of 73% for 1-benzhydryl-3-bromobenzene to 100% for 1-bromonapthalene in 18 h runs. The performance of TPAdFlMe and TPAdFlPh in photodehalogenation are already comparable to recently reported deazaflavin-based sensitizers, and we propose the transformation would proceed though the consecutive photo-induced electron transfer (conPET) mechanism with consecutive excitation of charged deazaflavin-based radicals under light irradiation as the key step to generating the aryl radicals, and the vital role of sensitizer-based radicals is further confirmed by mechanistic investigations. We expect the findings will help to design novel flavin-based triplet sensitizers for photoredox catalytic organic transformations. Full article

Selective inhibition of the tumour-associated carbonic anhydrase (CA) isoforms IX and XII, which are overexpressed in hypoxic tumours, has emerged as a promising strategy for the development of novel anticancer agents. Among the diverse CA inhibitors reported to date, coumarins have attracted particular attention. These chromenone derivatives, widely distributed in phytochemicals, display a broad range of biological activities and are known to act as suicide inhibitors of CAs. Following the tail approach, we designed a series of hybrid compounds combining a coumarin core with an N-arylthioureido scaffold located at the C-7 position and investigated how structural variations—including substituents on the coumarin and aromatic moieties, tether length, and urea/thiourea isosterism—influence their biological properties (CA inhibition and antiproliferative activity). Substituted coumarins at C-3 and C-4 were efficiently prepared via Pechmann condensation, while the thioureido motif was introduced using various aryl isothiocyanates as key synthetic intermediates. The lead compound, featuring a dimethylated coumarin, a pentyl linker, and an N-(p-tolyl)thioureido residue, inhibited the target enzymes in the low- to mid-nanomolar range (K_i = 6.0 and 49.9 nM, respectively), displaying selectivity indexes (S.I.s) surpassing those of the reference drug acetazolamide (AAZ). Moreover, it exhibited potent antiproliferative activity, with GI₅₀ values in the low micromolar range (1.9–3.5 µM) against both drug-sensitive and multidrug-resistant cancer cell lines. Label-free three-dimensional holotomographic microscopy revealed that this compound triggers slow apoptosis, leading to cell death after approximately 20 h of exposure. Full article

9-Mesitylacridinium salts are widely recognized as efficient organic photoredox catalysts owing to their strong excited-state oxidizing power and stability under visible-light irradiation. In this study, a new mesityl acridinium derivative bearing a di-tert-butylphenyl substituent on the nitrogen atom was synthesized. The introduction of tert-butyl groups on the N-aryl moiety was primarily aimed at improving solubility and chemical stability of the acridinium salt. Starting from a 9(10H)-acridinone precursor, the target compound was obtained in high overall yield through a concise synthetic sequence. The synthesis consists of a copper-catalyzed C–N coupling reaction to install the aryl substituent on the nitrogen atom, followed by a Grignard reaction and subsequent acid treatment to afford the corresponding acridinium salt. All transformations proceeded smoothly, providing efficient access to the desired novel acridinium derivative. This work presents a practical example of the structural modification of mesitylacridinium derivatives directed toward enhanced solubility and stability, and provides a useful synthetic platform for the preparation of structurally diverse acridinium salts. Full article

6(5H)-phenanthridinone derivatives, as an important class of alkaloids, have broad application value in drug development and functional material synthesis. In this study, a nickel-catalyzed synthetic strategy was developed, using 2-bromobenzamide compounds as starting materials. Through an intermolecular cyclization reaction, a series of 6(5H)-phenanthridinone derivatives bearing amide substituents was efficiently constructed. The optimal reaction system was identified: Ni(acac)₂/Zn as the catalyst, PCy₃ as the ligand, toluene as the solvent, Cs₂CO₃ as the base, under an argon atmosphere at 150 °C for 12 h. The target products were obtained in yields up to 88%. Further substrate scope exploration demonstrated the excellent generality of this method, successfully synthesizing 21 derivatives with various substitution patterns, achieving yields ranging from 51% to 92%, and showing good compatibility with multiple functional groups such as alkyl, aryl, and heterocyclic moieties. Importantly, the reaction remained stable during gram-scale experiments, successfully yielding the desired compound at 85%. This work not only provides an approach for the precise construction of the 6(5H)-phenanthridinone framework but also opens an efficient pathway for the controlled synthesis of amide-substituted derivatives. Full article

Background/Objectives: 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic environmental contaminant whose adverse biological effects are primarily mediated through activation of the aryl hydrocarbon receptor (AhR). Upon ligand binding, AhR undergoes conformational changes that initiate nuclear translocation and transcriptional activation of xenobiotic-responsive genes, contributing to toxicity, carcinogenesis, and dysregulated immune and metabolic responses. Understanding the molecular basis of AhR activation by TCDD is therefore critical for the rational development of targeted therapeutic strategies. Methods: In this study, molecular docking simulations were employed to characterize the interaction of TCDD and selected AhR antagonists (CH223191, BAY 2416964, GNF-351) with the ligand-binding domain of AhR, with particular emphasis on the canonical PAS-B domain. Results: Docking analyses identified the PAS-B cavity (pocket C1) as the most biologically relevant binding site for high-affinity ligands, consistent with experimental evidence. Comparative docking of known AhR antagonists revealed stable binding poses characterized by hydrophobic packing, π–π interactions, and hydrogen-bonding networks that competitively block agonist access and prevent receptor activation. These findings support a competitive antagonism mechanism as a viable approach to counteract TCDD-induced AhR signaling. Conclusions: Collectively, this in silico study provides mechanistic insight into TCDD toxicity at the molecular level and highlights AhR antagonism as a promising strategy for the development of targeted therapies against dioxin-related pathologies. Full article

Pyrrole derivatives are natural organic molecules that are important to the pharmaceutical industry due to their occurrence in nature and their use in a wide range of medical applications. In general, non-symmetric, 1,2,5-triaryl-substituted pyrroles are prepared either by Paal–Knorr condensation or cycloaddition that present synthetic challenges particularly if late-stage functionalization is required. The present study describes a modular approach to synthesizing 1,2,5-triarylpyrroles containing three different arene substituents. Using pyrrole ester building blocks, a sequence of decarboxylative cross-coupling and C–H arylation provides unsymmetrical 1,2,5-triarylpyrroles in a regioselective, stepwise manner; the scope and limitations of the sequence are disclosed. Full article

Antimicrobial resistance (AMR) remains a major threat to modern medicine, fueled by the excessive use of antibiotics and the spread of multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). In this study, we designed and synthesized a series of 2-aryl-4-aminoquinazoline derivatives bearing an aminoalkylimidazole linker, combining two pharmacophoric motifs associated with antimicrobial activity. Starting from anthranilamide, the compounds were prepared in three straightforward steps, affording good yields and high purity. Their structures were confirmed by FT-IR spectroscopy, ¹H and ¹³C nuclear magnetic resonance (NMR), and high-resolution mass spectrometry (HRMS). Biological evaluation showed that series 5 exhibited strong selectivity toward S. aureus, with compounds 5c and 5d displaying minimum inhibitory concentrations (MICs) between 2.2 and 4.4 µM. No significant activity was observed against other tested strains. Cytotoxicity assays in HepG2 cells revealed moderate to low inhibition. Molecular docking indicated preferential binding to dihydrofolate reductase (DHFR) and relevant interactions with topoisomerase IV, resembling reference inhibitors. ADME analysis predicted favourable absorption, blood–brain barrier permeability, and compliance with Lipinski’s rules. Full article

Under aqueous conditions, transition-metal catalysis offers an attractive platform for greener C–N bond formation by reducing reliance on hazardous organic solvents. Herein, we report a microwave-assisted palladium-catalyzed selective N-arylation of anilines with 2,3-dihalopyridines in water. Systematic optimization revealed that a catalyst system comprising PdCl₂(1,10-phenanthroline)₂ and (±)-BINAP in the presence of K₃PO₄ enables efficient coupling under microwave irradiation. Under the optimized conditions (PdCl₂(1,10-Phenanthroline)₂, 2 mol%; (±)-BINAP, 3 mol%; K₃PO₄, 3.5 equiv; H₂O, 2.5 mL; 150 °C; 30 min), the coupling of aniline with 2,3-dichloropyridine afforded the corresponding aminopyridine product in up to 91% isolated yield. The method was extended to various 2,3-dihalopyridines and substituted anilines, providing moderate to excellent yields with good regioselectivity. Mechanistically, the transformation is consistent with a Pd(0)/Pd(II) catalytic cycle involving oxidative addition, amido complex formation, and reductive elimination. Full article

We report an efficient synthetic method for the preparation of 6H-benzo[c]chromenes from substituted 1-(2′-bromo-[1,1′-biphenyl]-2-yl)-2-phenylethanols. These intermediates were obtained via a TDAE-initiated reaction between new substituted 2′-bromo-[1,1′-biphenyl]-2-carbaldehyde derivatives and substituted nitrobenzylic chlorides. The second step involved a palladium-catalyzed intramolecular O-arylation of the alcohol intermediate under microwave irradiation (110 °C for 1.5 h). The structure of 6H-benzo[c]chromene derivatives was confirmed by X-ray crystallography of product 5c. Full article

Two crystalline complexes, (2,2′-bipyridine)Cu(CH₃COO)₂·5H₂O (3) and (2,2′-bipyridine)Cu(CH₃COO)₂·CH₃CN (4), have been isolated and characterized by low-temperature single-crystal X-ray diffraction experiments. Crystals of phase 3 were studied previously at room temperature (296 K) under conditions leading to rapid desolvation and less distinct characterization of the waters of crystallization. With our redetermination of 3 at 100(2) K, we present a detailed description of ribbon-like structure formed by water molecules in crystals of (2,2′-bipyridine)Cu(CH₃COO)₂·5H₂O. Acetate oxygens are linked by hydrogen-bonding to two inequivalent waters separated by 4.72 Å; the other three water molecules are trapped in polymeric ribbons of anticooperative hydrogen-bonded six-membered rings fused with cooperative hydrogen-bonded four-rings. Water oxygens of the fused ring ribbons associate only with other water oxygens, and this water structure has a local density and pair distribution function which resembles that of liquid water. Crystals of 4 are monoclinic, with acetonitrile of solvation unassociated with the complex. In both 3 and 4, bipyridine planes interleave through π-aryl stacking. Full article

Methyl farnesoate (MF) is a sesquiterpenoid hormone that controls a variety of physiological processes in crustaceans, including morphogenesis, development, reproduction, and molting. MF action is mediated by a transcriptional signaling cascade consisting of Methoprene-tolerant (Met), Steroid receptor coactivator (Src), Krüppel homolog 1 (Kr-h1), and Ecdysone response gene 93 (E93) transcription factors (TFs), and transcriptional co-regulators CREB-binding protein (CBP) and C-terminal-binding protein (CtBP). Phylogenetic and sequence analyses revealed that these genes were highly conserved across pancrustacean species. Met and Src were characterized as basic helix-loop-helix, Period (Per)-Aryl Hydrocarbon Nuclear Translocator (ARNT)-Single-minded (Sim) protein (bHLH-PAS) TFs; Kr-h1 was characterized as a C₂H₂ zinc finger TF with seven zinc finger motifs; E93 was characterized as a helix-turn-helix, pipsqueak (HTH_Psq) TF. CBP was identified by several zinc finger-binding regions with Transcription Adaptor Zinc Finger 1 and 2, Really Interesting New Gene, Plant homeodomain, and Z-type zinc finger domains; the Kinase-inducible Domain Interacting-transcription factor docking site; the Bromodomain-acetylated lysine recognition and binding site; the histone acetyltransferase domain; and a C-terminal CREB-binding region containing a nuclear receptor co-activator-binding domain. CtBP had a dehydrogenase domain with arginine-glutamate-histidine catalytic triad. 81 Met contigs, 45 Src contigs, 136 Kr-h1 contigs, 66 E93 contigs, 60 CBP contigs, and 172 CtBP contigs were identified across pancrustacean taxa, including decapod crustaceans. Bioinformatic identification and annotation of these TFs and co-regulators in brachyuran Y-organ (YO) transcriptomes suggests that MF signaling influences YO ecdysteroidogenesis; functional tests in the YO are needed to establish causality. Full article