Search Results (160)

Background/Objectives: Antimicrobial resistance and bacterial persistence underscore the need to develop new chemotypes with multifunctional antibacterial mechanisms. This study aimed to design, synthesize, and evaluate curcumin-inspired 3,5-diarylidene-4-piperidones as versatile small molecules exhibiting antibacterial, antibiofilm, anti-efflux, DNA gyrase-inhibitory, and antiproliferative properties. Methods: A targeted series of triazole-conjugated 3,5-diarylidene-4-piperidones was synthesized through copper-catalyzed azide-alkyne cycloaddition click chemistry and subsequently characterized using standard spectroscopic techniques. The compounds were assessed for antibacterial activity against Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli. Selected active compounds underwent further evaluation for DNA gyrase inhibition, antibiofilm activity against multidrug-resistant S. aureus ATCC 33591, ethidium bromide accumulation, and antiproliferative effects on HCT116 and MCF7 cancer cells, with RPE1 cells serving as a control to evaluate cytotoxicity in normal cells. Additionally, computational studies, including QSAR analysis and molecular docking, were conducted to bolster structure–activity relationships and provide mechanistic insights. Results: Several derivatives demonstrated selective antibacterial activity against Gram-positive bacteria, particularly S. aureus, while exhibiting limited or no efficacy against E. coli. Compounds 7n and 7l emerged as the most potent against S. aureus, with minimum inhibitory concentrations (MICs) of 7.8 and 8.2 μM, respectively. Notably, compound 7l inhibited S. aureus DNA gyrase supercoiling, displaying an IC₅₀ of 3.20 μM, comparable to ciprofloxacin. Compound 7e exhibited the strongest antibiofilm activity against multidrug-resistant S. aureus, whereas compound 7a resulted in the highest accumulation of ethidium bromide, indicating robust anti-efflux activity. Antiproliferative assays revealed that select halogenated derivatives were effective against HCT116 and MCF7 cells, while the most promising antibacterial compounds exhibited minimal cytotoxicity toward RPE1 cells. Quantitative structure–activity relationship (QSAR) and docking studies supported the observed structure–activity relationships and suggested potential interactions with the ATPase binding site of DNA gyrase B. Conclusions: Triazole-conjugated 3,5-diarylidene-4-piperidones are promising multifunctional scaffolds with selective anti-S. aureus activity, antibiofilm and anti-efflux properties, and, for compound 7l, potent DNA gyrase inhibition. These findings support further optimization of this chemotype as a platform for developing antibacterial agents with polymechanistic activity. Full article

1,4-Disubstituted 1,2,3-triazoles are readily obtained by copper(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition (CuAAC)—the most widespread illustration of click chemistry to date. 1,2,3-Triazoles form a vast and easily accessible library of precursors for synthesizing 1,2,3-triazolium ionic liquids (TILs). A series of four 1,3,4-trisubstituted TILs with N-1-n-octyl, N-3-methyl and different C-4 substituents (i.e., aromatic, aliphatic, PEGylated and perfluorinated groups) is synthesized in two steps involving: (i) CuAAC to generate 1,2,3-triazole precursors and (ii) N-alkylation of the 1,2,3-triazole groups with methyl iodide to afford the corresponding 1,2,3-triazolium salts with iodide counter-anions. A thorough investigation of the correlations between structure and properties is carried out using NMR spectroscopy, high-resolution mass spectrometry, differential scanning calorimetry, thermogravimetric analysis and broadband dielectric spectroscopy. The PEGylated TIL has also undergone ion metathesis to produce the TIL analogue with a bis(trifluoromethylsulfonyl)imide counter-anion. Of all the synthesized TILs, this derivative exhibits the lowest glass transition temperature (T_g = −76 °C), the highest thermal stability (T_d10 = 345 °C) and the greatest ionic conductivity (σ_DC = 6.5 × 10⁻⁴ S cm⁻¹ at 30 °C under anhydrous conditions). Full article

Click chemistry is highly valued in the design of polymeric biomaterials due to its ability to generate complex structures and localized surface modifications. However, prominent mechanisms in click chemistry, such as copper-catalyzed azide-alkyne cycloaddition (CuAAC), are inefficient for the synthesis and/or modification of biomaterials because they present significant limitations for in vivo applications. The presence of residual copper in the material is toxic and requires extensive purification, increasing production costs and hindering scalability and availability for in vivo applications. To overcome these limitations and ensure the safety and biocompatibility of materials, biorthogonal reactions such as strain-promoted azide-alkyne cycloaddition (SPAAC) have been developed. Thiol-ene/thiol-yne and Diels–Alder mechanisms are also relevant for the formation of robust polymer networks with specific characteristics and attractive advantages for generating biocompatible materials. These reactions not only improve cell integration and reduce fibrosis in in vivo applications but also enable the creation of functional structures for tissue regeneration. This review provides a comprehensive analysis of advances in the synthesis of biomaterials for tissue regeneration using hydrogels designed via click chemistry, as well as the various mechanisms and structural considerations. Full article

A synthetically accessible library of N-acyl sulfonamides was constructed using a combination of copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) and N-acylation of primary sulfonamides. The proposed two-step reaction sequence had a high experimentally confirmed synthetic success rate (up to 85%) and gave reasonable product yields (up to 61%). As a result of the validation process, a 262-member compound library (out of >70K accessible combinations) was prepared. Biological profiling of the synthesized library by differential scanning fluorimetry and enzymatic assays identified several low micromolar inhibitors of human carbonic anhydrase. The interaction of the discovered hits with the biological target was studied by docking and molecular dynamics. Full article

A series of azide- and cyclooctyne-functionalized N-hydroxysuccinimidyl esters (NHS esters) and benzotriazolides were prepared and used as N-acylation reagents to obtain azide-(BSA-1) and cyclooctyne-functionalized bovine serum albumin proteins (BSA-2), fluorescein derivatives 5 and 6, and homobifunctional linkers 3 and 4. Strain-promoted azide-alkyne cycloaddition (SPAAC) and copper-catalyzed azide-alkyne cycloaddition (CuAAC) of azide-functionalized fluorescent probe 5 and alkyne-functionalized fluorescent probe 6 with complementary functionalized proteins BSA-2 and BSA-1 yielded fluorescent cycloadducts BSA-2-5 and BSA-1-6. These cycloadducts were used to determine the loading of BSA-1 and BSA-2 with the respective azido and cyclooctyne groups based on their molar absorbances and fluorescence intensities. Dimerization through covalent cross-linking of BSA was then performed by SPAAC between azide-functionalized BSA-1 and cyclooctyne-functionalized BSA-2, and by treating BSA-1 and BSA-2 with 0.5 equiv. of complementary bis-cyclooctyne linker 4 and bis-azide linker 3. Although the formation of covalent dimers BSA-1-2-BSA, BSA-1-6-1-BSA, and BSA-2-5-2-BSA was detected by SDS-PAGE analysis, this was a minor process, and most of the functionalized BSA did not form covalent dimers. Full article

As eco-friendly processes become central to modern organic synthesis, plant-based materials are emerging as attractive alternatives for both nanoparticle fabrication and catalysis. In this study, we explore the use of clove extract, a natural and renewable resource, for the green synthesis of copper oxide (CuO) nanoparticles and their subsequent application in organic transformations. Clove extract was employed to reduce copper chloride via a simple co-precipitation method under mild conditions, yielding CuO nanoparticles characterized by XRD, FTIR, and SEM-EDX techniques. These nanoparticles were then used as catalysts in the copper-catalyzed azide–alkyne cycloaddition (CuAAC) to afford eugenol-based 1,2,3-triazoles in excellent yields. This dual use of clove extract exemplifies a sustainable approach that merges natural product valorization with efficient catalysis for triazole synthesis. Full article

Mechanochemical and transition-metal-catalyzed reactions of alkynes, exhibiting significant advantages like short reaction time, solvent-free, high yield and good selectivity, were considered to be green and sustainable pathways to access functionalized molecules and obtained increasing attention due to the superiorities of mechanochemical processes and the reactivities of alkynes. The ball milling and CuI-catalyzed Sonogashira coupling of alkyne and aryl iodide avoided the use of common palladium catalysts. The mechanochemical Rh(III)- and Au(I)-catalyzed C–H alkynylations of indoles formed the 2-alkynylated and 3-alkynylated indoles selectively. The mechanochemical and copper-catalyzed azide-alkyne cycloaddition (CuAAC) between alkynes and azides were developed to synthesize 1,2,3-triazoles. Isoxazole could be formed through ball-milling-enabled and Ru-promoted cycloaddition of alkyne and hydroxyimidel chloride. In this review, the generation of mechanochemical and transition-metal-catalyzed reactions of alkynes was highlighted. Firstly, the superiority and application of transition-metal-catalyzed reactions of alkynes were briefly introduced. After presenting the usefulness of green chemistry and mechanochemical reactions, mechanochemical and transition-metal-catalyzed reactions of alkynes were classified and demonstrated in detail. Based on different kinds of reactions of alkynes, mechanochemical and transition-metal-catalyzed coupling, cycloaddition and alkenylation reactions were summarized and the proposed reaction mechanisms were disclosed if available. Full article

6-Aryl-7H-pyrrolo[2,3-d]pyrimidin-4-amines have promising properties as colony-stimulating factor 1 receptor (CSF1R) inhibitors. Inspired by these antagonists, two series of 1,2,3-triazole analogues (28 compounds) were synthesized and evaluated as CSF1R inhibitors. Enzymatic IC₅₀ profiling showed that 27 of the 28 derivatives had lower IC₅₀ than the reference drug PLX-3397. Three derivatives displayed CSF1R Ba/F3 cellular IC₅₀ well below 1 µM. Profiling of the most promising triazole analogue (compound 27a) toward a panel of kinases reveals a high selectivity for CSF1R with respect to its family kinases, but 27a also inhibits ABL, SRC, and YES kinases. Molecular docking of 27a toward two CSF1R X-ray structures identified two different ligand-inverted binding poses, which triggers interest for further investigations. Full article

Over the past two decades, the copper(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition (CuAAC), commonly known as click chemistry, and C–H bond activation have gained significant attention and have emerged as key synthetic methodologies. In our efforts to synthesize fused nitrogen-containing heterocycles, we developed a palladium-catalyzed protocol for the synthesis of functionalized 7,10-dihydropyrrolo[3,2,1-ij][1,2,3]triazolo[4,5-c]quinolines and 5,8-dihydrobenzo[3,4][1,2,3]triazolo[4′,5′:5,6]azepino[1,2-a]indoles from suitable bromo-substituted N-propargyl-indoles. The reaction conditions demonstrate broad functional group compatibility including halogen, alkoxyl, cyano, ketone, and ester, affording the target compounds in good to high yields. Full article

Background/Objectives: In this study, a novel series of 4-(arylchalcogenyl)methyl)-1H-1,2,3-Triazol-1-yl-menadione derivatives were synthesized to explore their potential as new antituberculosis (anti-TB) agents. Selenium-containing compounds are known for their significant antimycobacterial activity, which motivated their inclusion in the design. Methods: The target compounds were synthesized via a copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, affording yields ranging from 34% to 93%. All compounds were evaluated in vitro for anti-TB activity against Mycobacterium tuberculosis H37Rv (ATCC 27294), as well as a drug-resistant strain (T113/09). Results: Several selenium-containing derivatives exhibited promising activity. Compounds 9b and 9g were equipotent to the first-line anti-TB drug, and one compound surpassed its activity. Notably, compounds 9a, 9b, 9g, and 9h also showed efficacy against the INH- and RIF-resistant Mtb strain T113/09. Conclusions: The efficacy of selenium-containing triazole-menadione hybrids against both sensitive and resistant Mtb strains highlight their potential as candidates for addressing antimicrobial resistance in TB treatment. Further investigations are required to understand their mechanisms of action and assess their in vivo therapeutic potential.. Full article

Morquio A syndrome is a lysosomal disorder caused by the deficiency of the lysosomal enzyme N-acetylgalactosamine 6-sulfatase (GALNS, EC 3.1.6.4). Currently, enzyme replacement therapy (ERT) is used to treat Morquio A through the infusion of the recombinant enzyme VIMIZIM^® (elosulfase alfa, BioMarin). Unfortunately, the recombinant enzyme exhibits low conformational stability in vivo. A promising approach to address this issue is the coadministration of recombinant human GALNS (rhGALNS) with a pharmacological chaperone (PC), a molecule that selectively binds to the misfolded protein, stabilizes its conformation, and assists in the restoration of the impaired function. We report in this work the synthesis of a library of multivalent glycomimetics exploiting the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction between several dendrimeric scaffolds armed with terminal alkynes and azido ending iminosugars of different structures (pyrrolidines, piperidines, and pyrrolizidines) or simple azido ending carbohydrates as bioactive units. The biological evaluation identified pyrrolidine-based nonavalent dendrimers 1 and 36 as the most promising compounds, able both to bind the native enzyme with IC₅₀ in the micromolar range and to act as enzyme stabilizers toward rhGALNS in a thermal denaturation study, thus identifying promising compounds for a combined PC/ERT therapy. Full article

Parasitic diseases represent a severe global burden, with current treatments often limited by toxicity, drug resistance, and suboptimal efficacy in chronic infections. This review examines the emerging role of triazole-based compounds, originally developed as antifungals, in advanced antiparasitic therapy. Their unique structural properties, particularly those of 1,2,3- and 1,2,4-triazole isomers, facilitate diverse binding interactions and favorable pharmacokinetics. By leveraging innovative synthetic approaches, such as click chemistry (copper-catalyzed azide–alkyne cycloaddition) and structure-based design, researchers have repurposed and optimized triazole scaffolds to target essential parasite pathways, including sterol biosynthesis via CYP51 and other novel enzymatic routes. Preclinical studies in models of Chagas disease, leishmaniasis, malaria, and helminth infections demonstrate that derivatives like posaconazole, ravuconazole, and DSM265 exhibit potent in vitro and in vivo activity, although their primarily static effects have limited their success as monotherapies in chronic cases. Combination strategies and hybrid molecules have demonstrated the potential to enhance efficacy and mitigate drug resistance. Despite challenges in achieving complete parasite clearance and managing potential toxicity, interdisciplinary efforts across medicinal chemistry, parasitology, and clinical research highlight the significant potential of triazoles as components of next-generation, patient-friendly antiparasitic regimens. These findings support the further optimization and clinical evaluation of triazole-based agents to improve treatments for neglected parasitic diseases. Full article

This study presents a tentative synthesis of supported H-shaped and ladder-type compounds. If the ladders were not accessible, probably due to distance misfits between the reactive centers, a facile method for the synthesis of H-shaped N-alkylated aminomethyl oligobenzamides, i.e., arylopeptoids by on-resin homodimerization via the Copper(I)-Catalyzed-Alkyne-Azide-Cycloaddition (CuAAC) reaction is reported. While successful, a synthetic bottleneck was identified for further oligomer elongation due to congestion when the ligation occurs on solid support. However, this issue was effectively addressed using an elongated oligomer to conduct inter-strand cross-linking. Further CuAAC functionalization could be performed after elongation with additional alkyne groups to enhance diversity. Full article

Numerous emerging chemotherapeutic agents incorporate N-heterocyclic fragments in their structures, with the quinoline skeleton being particularly significant. Our recent works have focused on glycoconjugates of 8-hydroxyquinoline (8-HQ), which demonstrated enhanced bioavailability and solubility compared to their parent compounds, although they fell short in selectivity. In this study, our objective was to improve the selectivity of glycoconjugates by replacing the oxygen atom with nitrogen by substituting the 8-HQ moiety with 8-aminoquinoline (8-AQ). The 8-AQ derivatives were functionalized through the amino group and linked to sugar derivatives (D-glucose or D-galactose) that were modified with an azide, alkylazide, or propargyl group at the anomeric position by copper(I)-catalyzed 1,3-dipolar azido-alkyne cycloaddition (CuAAC). The resulting glycoconjugates, as well as their potential metabolites, were evaluated for their ability to inhibit the proliferation of cancer cell lines (including HCT 116 and MCF-7) and a healthy cell line (NHDF-Neo). Two of the synthesized glycoconjugates (17 and 18) demonstrated higher cytotoxicity than their oxygen-containing counterparts and showed improved selectivity for cancer cells, thus enhancing their anticancer potential. Furthermore, it was found that glycoconjugates exhibited greater cytotoxicity in comparison to their potential metabolites. Full article

Cellulose tosylate (MCC-Tos) is a key derivative for surface modification and a crucial precursor for cellulose compatibilization in click reactions, enabling its functionalization for advanced applications. Replacing tosyl groups with alkyne groups broadens cellulose’s potential in biocompatible reactions, such as thiol-yne click chemistry and protein/enzyme immobilization. To achieve this, we optimized the heterogeneous synthesis of MCC-Tos using a Doehlert matrix statistical design, evaluating the influence and interaction of the reaction conditions. The optimized conditions—144 h reaction time, 10:1 molar ratio, and 30 °C—yielded a degree of substitution for tosyl groups (DS_tos) of 1.80, determined via elemental analysis and FTIR-ATR spectroscopy. The reaction kinetics followed a first-order model. A subsequent reaction with propargylamine produced aminopropargyl cellulose (MCC-P_NH), reducing DS_tos by 65%, which was confirmed via FTIR, and improving thermal stability by a margin of 30 °C (TGA/DTG). ¹³C CP/MAS NMR confirmed the alkyne group attachment, further validated via coupling an azide-functionalized coumarin through copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC). Fluorescence microscopy and UV spectroscopy were used to estimate a substitution degree of 0.21. This study establishes a feasible route for synthesizing alkyne-functionalized cellulose, paving the way for eco-friendly materials, including protein/enzyme bioconjugates, composites, and advanced materials via thiol-yne and CuAAC reactions. Full article