Alkyne Cycloaddition Reaction Research Articles

Coumarin‐Tethered‐1,2,3‐Triazoles: Synthesis, Characterization, Antimicrobial Evaluation, and DFT Studies

AbstractA new series of Coumarin‐tethered‐1,2,3‐triazoles (7a–i and 9a–f) were synthesized by the copper‐assisted 1,3‐dipolar cycloaddition reaction of coumarin alkyne (5) with variedly substituted azides (6a–I and 8a–f). All the synthesized compounds were spectroscopically characterized and in vitro antimicrobial testing against a panel of bacterial and fungal strains was systematically carried out. The compounds bearing 3‐Cl (7b) and 2‐NO2 (7i) substituents which emerged as the most potent compounds of the series showed noticeable activity against Staphylococcus aureus. Additionally, density functional theory (DFT) calculations were conducted to explore the chemical reactivity and stability parameters of the compounds.

Microwave expedited Cu(I) catalyzed regioselective 1,2,3-triazoles as Mycobacterium Tuberculosis H37Rv inhibitors, in vitro α-amylase and α-glucosidase inhibition, in silico studies

In the present study, an efficient and convenient synthesis of novel 1,2,3-triazoles (8i-t) incorporated quinoline and coumarin cores has been reported. Microwave-assisted Huisgen 1,3-dipolar cycloaddition reaction of azide and alkyne resulted in high yields (88–94 %) of the title compounds. Regioselective single-product formation both under conventional and microwave methods is the foremost supremacy of this work. All the molecules were subjected to in vitro antibacterial assessment wherein the compounds 8i, 8k, 8l, 8n, and 8r demonstrated very good antibacterial activity against other bacterial strains tested. Compounds 8i, 8k, 8l, 8n, 8o, 8q, and 8r demonstrated excellent antitubercular activity with MICs in the range 1.60–6.25 µg/mL in comparison to the standard drugs (Isoniazid-1.60 µg/mL, Ciprofloxacin-3.25 µg/mL, Pyrazinamide-6.25 µg/mL). Compounds 8i, 8n, and 8r also exhibited inhibitory effects against α-amylase and α-glucosidase and thus, also showed anti-diabetic activity. The significantly active compounds were subjected to molecular docking and molecular dynamics simulation studies to study the putative binding pattern as well as the stability of the docked complexes, respectively. In silico ADME profiles of the titled compounds were also predicted to access the drug-likeness properties of the designed compounds. Titled compounds showed potential effectiveness as antibacterial and antidiabetic agents.

Oxidation-Controlled, Strain-Promoted Tellurophene-Alkyne Cycloaddition (OSTAC): A Bioorthogonal Tellurophene-Dependent Conjugation Reaction.

Tellurophene-bearing small molecules have emerged as valuable tools for localizing cellular activities in vivo using mass cytometry. To broaden the utility of tellurophenes in chemical biology, we have developed a bioorthogonal reaction to facilitate tagging of tellurophene-bearing conjugates for downstream applications. Using TePhe, a tellurophene-based phenylalanine analogue, labeled recombinant proteins were generated for reaction development. Using these proteins, we demonstrate an oxidation-controlled, strain-promoted tellurophene-alkyne cycloaddition (OSTAC) reaction. Mild oxidation of the tellurophene ring with N-chlorosuccinimide produces a reactive Te(IV) species which undergoes rapid (k > 100 M-1 s-1) cycloaddition with bicyclo[6.1.0]nonyne (BCN) yielding a benzo-fused cyclooctane. Selective labeling of TePhe-containing proteins can be achieved in complex protein mixtures and on fixed cells. OSTAC reactions can be combined with strain-promoted azide alkyne cycloaddition (SPAAC) and copper-catalyzed azide alkyne click (CuAAC) reactions. Demonstrating the versatility of this approach, we observe the expected staining patterns for 5-ethynyl-2'-deoxyuridine (DNA synthesis-CuAAC) and immunohistochemistry targets in combination with TePhe (protein synthesis-OSTAC) in fixed cells. The favorable properties of the OSTAC reaction suggest its broad applicability in chemical biology.

A Review of the Use of the Nickel Catalyst in Azide‐Alkyne Cycloaddition Reactions

ABSTRACTTrying to find beneficial and effective catalysis for synthesizing biologically active and valuable 1,2,3‐triazoles is continually being studied to make the procedure more efficient, green, and eco‐friendly. The click reaction is famous in green chemistry for its high selectivity and efficiency in generating 1,2,3‐triazoles with important pharmaceutical and biological activities. 1,3‐Dipolar cycloaddition reaction of organic azides and alkynes by copper‐mediated have a great deal of attention paid to and developed to provide 1,2,3‐triazoles. However, utilizing Cu(II) species frequently requires a reducing reagent, making this approach less atom‐economic. Recently, notable progress has been made in designing and developing metal‐catalyzed click reactions to prepare 1,2,3‐triazoles. As appropriate alternatives to copper catalysts, nickel catalysts can be a good choice in click reactions. This review thoroughly studies the excellent potential of nickel catalysts in azide‐alkyne cycloaddition reactions and recommends using them as proper alternatives to traditional copper catalysts. This review can pave the path for further application of nickel catalysts in click reactions.

Enzyme-free fluorescent DNA detection based on nucleic acid-templated click reaction via controllable synthesis of Cu2O as heterogeneous nanocatalyst

In the field of nucleic acid amplification assays, developing enzyme-free, easy-to-use, and highly sensitive amplification approaches remains a challenge. In this work, we synthesized a heterogeneous Cu2O nanocatalyst (hnCu2O) with different particle sizes and shapes, which was used for developing enzyme- and label-free nucleic acid amplification methods based on the nucleic acid-templated azide–alkyne cycloaddition (AAC) reaction catalyzed by hnCu2O. The hnCu2O exhibited size- and shape-dependent catalytic activity, with smaller sizes and spherical-like shapes exhibiting superior activity. Spherical-like hnCu2O (61 ± 8 nm) not only achieved a ligation yield of up to 84.2 ± 3.9 % in 3 min but also exhibited faster kinetics in the nucleic acid-templated hnCu2O-catalyzed AAC reaction, with a high reaction rate of 0.65 min−1 and a half-life of 1.07 ± 0.09 min. Based on this result, we developed nucleic acid-templated click ligation linear amplification reaction (NA-CLLAR) and nucleic acid-templated click ligation exponential amplification reaction (NA-CLEAR) approach. By combining the recognition (complementary to the target sequence) and signal output (split G-quadruplex sequence) elements into a DNA probe, the NA-CLLAR and NA-CLEAR fluorescence assays achieved highly specific detection of target nucleic acids, with a detection limit of 2.8 aM based on G-quadruplex-enhanced fluorescence. This work is a valuable reference and will inspire researchers to design enzyme-free nucleic acid signal amplification strategies by developing different types of Cu(I) catalysts with improved catalytic activity.

Indole–thiazolidinedione–triazole hybrids: synthesis, molecular docking, absorption, distribution, metabolism and excretion (ADME) profiling, and biological evaluation as α-amylase inhibitors

Abstract A novel series of hybrid indole–thiazolidinedione–triazole derivatives (6a-l) were synthesized and assessed for their in vitro inhibitory activity against porcine pancreatic α-amylase. The synthetic procedure consists of 3 steps. A crucial step in this process involves the generation of novel target molecules using a Cu(I)-catalyzed azide–alkyne cycloaddition reaction. The α-amylase inhibition IC50 value of the targeted compounds ranged from 0.51 ± 0.02 to 7.99 ± 0.28 μM as compared with 0.68 ± 0.02 μM with acarbose as the standard drug. Using the Autodock technique, all the derivatives 6a-l were subjected to molecular docking investigations against porcine pancreatic α-amylase (PDB ID: 1OSE). Moreover, it was discovered that the docked compounds had excellent binding affinities that ranged from −10.1 to −10.8 kcal/mol as compared with the standard −7.9 kcal/mol. Additionally, a comprehensive analysis of the physicochemical and pharmacokinetic properties associated with absorption, distribution, metabolism and excretion (ADME) was conducted for all the synthesized compounds.

Copper and silver nano-schiff base complexes: Efficient catalysts for triazole synthesis and antimicrobial assessment

1,2,3-Triazoles are one of the most important nitrogen-containing five-membered heterocycles and have a wide range of applications in pharmaceuticals, chemical biology, and industry. Therefore, the development of facile and straightforward methodology for the synthesis of 1,2,3-triazoles is of noteworthy interest. Click chemistry represents the most facile, easy and one pot reaction method to synthesize catalyzed azide–alkyne cycloaddition reaction. Nano-scaled bis(2‑hydroxy-1-naphthylmethylidene) ethane-1,2-diamine copperII [CuSB1] and nano-silver ethane-1,2-diamine bis(2-hydroxy-1-naphthylmethylidene) [AgHSB2] complexes where H2SB= 1,2-diamino ethane-N,N’-bis(2-hydroxy-1-naphthylmethylidene), were synthesized utilizing ultrasonic green method. The catalysts were examined by elemental analyses, molar conductance, and spectrophotometric tests. The optimized geometrical structures of H2SB, [CuSB1], [AgHSB2], and HOMO–LUMO representations were performed by Cluster calculations using DMOL3 program. TEM images showed narrower morphology and regular nanostructures of the catalysts. CuSB1] and [AgHSB2] exhibit efficient catalytic activity to prepare different triazoles (3–8). using single-pot selective cycloaddition reaction within very short time and excellent yield without presence of biproducts. The complexes [CuSB1], [AgHSB2] and the triazoles 3, 4, as representative examples, have efficient antimicrobial activity making them promising drugs for treating the bacterial and fungal infections.

Cu‐Catalyzed Synthesis of Coumarin‐1,2,3‐Triazole Hybrids connected with Quinoline or Pyridine Framework**

AbstractCoumarin‐1,2,3‐triazole hybrids connected to quinoline or pyridine framework have been synthesized in good to excellent yield by the 1,3‐dipolar azide alkyne cycloaddition reaction (CuACC) of 4‐azidocoumarin with propargyl quinoline or propargyl pyridine derivatives in the presence of CuSO4.5H2O or CuI as catalyst. Similar reaction of 4‐azidocoumarin or tetrazolo[1,5‐a]pyridine with 4‐propargyloxycoumarin and 4‐propargylaminocoumarin resulted in the synthesis of the corresponding coumarin‐1,2,3‐triazole hybrids. Some preliminary screening test for some biological activities of new compounds have been performed.

Ultrasound-assisted Cu(II) Strecker-functionalized organocatalyst for green azide–alkyne cycloaddition and Ullmann reactions

A new aminonitrile-functionalized Fe3O4 has been synthesized via the Strecker reaction, the designed aminonitrile ligand on the surface of the magnetic core coordinated to copper(II) to obtain the final new catalyst. The fabricated nanocatalyst was characterized by Fourier transform Infrared (FT-IR), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray spectroscopy (EDX), Transmission Electron Microscopy (TEM), Vibrating-Sample Magnetometer (VSM), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), and Thermogravimetric Analysis (TGA). The high tendency of nitrogens in the aminonitrile functional group to make a complex with Cu(II) has caused the practical activity of this nucleus in this catalyst. This nanocatalyst performance was investigated in azide–alkyne Huisgen cycloaddition (3 + 2) reaction for achieving to 1,4-disubstituted 1,2,3-triazoles in water as a green media at room temperature. In another try, Classic Ullmann Reaction was investigated for the synthesis of biaryls at 85 °C promoted by ultrasonic condition (37 kHz). The reaction scope was explored using different reactants and the results of using this developed catalytic system demonstrated its capacity to reduce the reaction time and enhance the reaction efficiency to provide good to excellent product yield. Conversely, the simple recycling and reusability of this catalyst for at least six times without any noticeable leaching of copper makes it a potential future catalyst for synthesizing such compounds.

Synthesis, DFT calculations, and investigation of catalytic and biological activities of back‐bond functionalized re‐NHC‐Cu complexes

Five copper complexes (3a–e) stabilized by ring‐expanded back‐bond functionalized N‐heterocyclic carbene ligands (re‐NHCs) were produced in the glovebox by reacting free re‐NHC with CuI precursor. The potential of these re‐NHC‐Cu complexes as catalysts on the synthesis of mono‐ and di‐(1,4‐disubstituted‐1,2,3‐triazoles) by Cu‐catalyzed azide–alkyne cycloaddition (CuAAC) reactions was investigated. Various spectroscopic approaches were utilized to completely characterize the structures of the re‐Cu‐NHC complexes. Furthermore, density functional theory (DFT) calculations were carried out to get further insights into their molecular geometry and CuAAC reaction mechanism. The re‐NHC‐Cu complexes showed high activity on the CuAAC reaction in an open‐air atmosphere at rt. The Gibbs free energies as well as the optimized geometries of the intermediates and the transition states of the determining step of the reactions catalyzed by 3a, 3e, and 3b complexes were computed. Complex 3e was found to be the most efficient catalyst among these re‐NHC‐Cu complexes. Additionally, re‐Cu‐NHC complexes were investigated for their biological activities, including antiproliferative, antioxidant, AChE and TyrE inhibition, and antiparasitic activity. The results showed that the 3b, 3d, and 3e complexes possessed strong antiproliferative activity against human colon carcinoma (HCT‐116) and moderate cytotoxic activity against hepatocellular carcinoma (HepG‐2) cell lines. In addition, effective selective antileishmanial effects were observed for the 3e compound against both promastigotes and amastigotes stages of L. major with an IC50 value of 0.027 and 0.39 μM mL−1, respectively. These results demonstrate that these compounds are promising candidates for the treatment of colorectal cancer and leishmaniasis.

Pyrano[2,3-c]pyrazole fused spirooxindole-linked 1,2,3-triazoles as antioxidant agents: Exploring their utility in the development of antidiabetic drugs via inhibition of α-amylase and DPP4 activity

Environment-benign, multicomponent synthetic methodologies are vital in modern pharmaceutical research and facilitates multi-targeted drug development via synergistic approach. Herein, we reported green and efficient synthesis of pyrano[2,3-c]pyrazole fused spirooxindole linked 1,2,3-triazoles using a tea waste supported copper catalyst (TWCu). The synthetic approach involves a one-pot, five-component reaction using N-propargylated isatin, hydrazine hydrate, ethyl acetoacetate, malononitrile/ethyl cyanoacetate and aryl azides as model substrates. Mechanistically, the reaction was found to proceed via in situ pyrazolone formation followed by Knoevenagel condensation, azide alkyne cycloaddition and Michael's addition reactions. The molecules were developed using structure-based drug design. The primary goal is to identifying anti-oxidant molecules with potential ability to modulate α-amylase and DPP4 (dipeptidyl-peptidase 4) activity. The anti-oxidant analysis, as determined via DPPH, suggested that the synthesized compounds, A6 and A10 possessed excellent anti-oxidant potential compared to butylated hydroxytoluene (BHT). In contrast, compounds A3, A5, A8, A9, A13, A15, and A18 were found to possess comparable anti-oxidant potential. Among these, A3 and A13 possessed potential α-amylase inhibitory activity compared to the acarbose, and A3 further emerged as dual inhibitors of both DPP4 and α-amylase with anti-oxidant potential. The relationship of functionalities on their anti-oxidant and enzymatic inhibition was explored in context to their SAR that was further corroborated using in silico techniques and enzyme kinetics.

Synthesis and characterization of a new copper-based polyoxomolybdate and its catalytic activity for azide-alkyne cycloaddition reaction under UV light irradiation

A new organic-functionalized Cu-based Anderson-type polyoxomolybdate, namely (C7H15N4)2[Na(H2O)4]2[C6H12CuMo6N2O24]·2(H2O) (CuII-POM), was synthesized via a simple one-pot reaction and subsequently characterized using a range of analytical and spectral techniques. Structural investigation by single crystal X-ray diffraction analysis revealed that the polyanion component of the synthesized compound (i.e. [C6H12CuMo6N2O24]4−) possesses a δ-isomer Anderson-type structure, which is surrounded by four lattice water molecules and four [C7H15N4–NaH15(H2O)8]4+ cations in the crystal packing arrangement. The resulting double-sided tris-functionalized Anderson-type compound can function as highly effective heterogeneous photocatalysts for the copper(I)-catalyzed Huisgen azide-alkyne cycloaddition (Cu-AAC) reaction of terminal alkyne, benzyl halides, and sodium azide (acts as the azidonation and reducing agent) in aqueous media. Ultraviolet light irradiation enhances the catalytic activity of CuII-POM ~ 4.4 times of the “off” situation under reaction conditions of 0.00239 mmol cat., 80 °C, 8 h, 2 mL H2O, So that the isolated yields for the AAC reaction involving a variety of terminal alkynes and benzyl halides using the CuII-POM catalyst ranged between 19–97%. The current study is the first report about using an efficient and economical Cu(II)-POM/UV/NaN3 catalytic system in the Cu-AAC reaction and reveals its significant potential for applying to other Cu(I)-catalyzed reactions.

Click synthesis of novel 6-((1H-1,2,3-triazol-4-yl)methyl)-6H-indolo[2,3-b]quinoxalines for in vitro anticancer evaluation and docking studies

Anticancer activity, a novel series of 6-((1H-1,2,3-triazol-4-yl)methyl)-6H-indolo[2,3-b]quinoxalines (22–29) were designed and synthesized via the copper(i)-catalyzed azide–alkyne cycloaddition (CuAAC) reactions.

On the mechanochemical synthesis of C-scorpionates with an oxime moiety and their application in the copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction

Integrating the principles of green chemistry to develop sustainable processes.

The Covalent Linking of Organophosphorus Heterocycles to Date Palm Wood-Derived Lignin: Hunting for New Materials with Flame-Retardant Potential

Environmentally acceptable and renewably sourced flame retardants are in demand. Recent studies have shown that the incorporation of the biopolymer lignin into a polymer can improve its ability to form a char layer upon heating to a high temperature. Char layer formation is a central component of flame-retardant activity. The covalent modification of lignin is an established technique that is being applied to the development of potential flame retardants. In this study, four novel modified lignins were prepared, and their char-forming abilities were assessed using thermogravimetric analysis. The lignin was obtained from date palm wood using a butanosolv pretreatment. The removal of the majority of the ester groups from this heavily acylated lignin was achieved via alkaline hydrolysis. The subsequent modification of the lignin involved the incorporation of an azide functional group and copper-catalysed azide–alkyne cycloaddition reactions. These reactions enabled novel organophosphorus heterocycles to be linked to the lignin. Our preliminary results suggest that the modified lignins had improved char-forming activity compared to the controls. 31P and HSQC NMR and small-molecule X-ray crystallography were used to analyse the prepared compounds and lignins.

Design and Synthesis of Novel 1‐((1‐Phenyl‐1H‐1,2,3‐triazol‐4‐yl)methyl)pyridin‐2(1H)‐one Derivatives

AbstractThe synthesis of a new class of compounds, namely 1‐((1‐phenyl‐1H‐1,2,3‐triazol‐4‐yl)methyl)pyridin‐2(1H)‐one derivatives starting from 2‐hydroxynicotinic acid was reported. Initially, the carboxylic acid functionality connected to the pyridinone ring was converted to either the ester, amide or aldehyde functionality to obtain the precursor for the propargylation step. The incorporation of a propargyl group into the nitrogen atom of pyridinones was achieved in the presence of K2CO3 as a base. Different organic azides were also synthesized starting from the corresponding aniline derivatives. To obtain target molecules, the facile click cycloaddition reactions of alkynes with aryl azide derivatives in the presence of copper(I) catalyst were applied. Using this protocol, novel 1‐((1‐phenyl‐1H‐1,2,3‐triazol‐4‐yl)methyl)pyridin‐2(1H)‐one derivatives with different substitution patterns were prepared in good to excellent yields under the mild reaction conditions. The structures of the compounds were confirmed by 1D and 2D NMR, FTIR, and HRMS analysis data. Overall, this protocol offers a straightforward method for synthesizing these novel compounds.

Goldkatalysierte formale [4+2]‐Cycloaddition als Zugang zu antitumoraktiven spirozyklischen Oxindolen aus Alkinen und von Isatin abgeleiteten Ketiminen

AbstractAufgrund seines hervorragenden Bioaktivitätsprofils, das zunehmend in der pharmazeutischen und synthetischen Chemie genutzt wird, ist Spirooxindol ein wichtiger Grundbaustein. Wir beschreiben hier eine effiziente Methode zum Aufbau hochfunktionalisierter neuer Spirooxindolocarbamate über eine Gold‐katalysierte Cycloadditionsreaktion von terminalen Alkinen oder Inamiden mit von Isatin abgeleiteten Ketiminen. Dieses Protokoll weist eine gute Kompatibilität mit funktionellen Gruppen auf, verwendet leicht verfügbare Ausgangsstoffe, milde Reaktionsbedingungen, geringe Katalysatorbeladungen und keine Additive. Es ermöglicht die Umwandlung verschiedener funktionalisierter Alkingruppen in zyklische Carbamate. Es gelang eine Synthese im Grammmaßstab und DFT‐Berechnungen bestätigen die Machbarkeit des mechanistischen Ansatzes. Einige der Zielprodukte zeigen eine gute bis ausgezeichnete antiproliferative Aktivität auf menschlichen Tumorzelllinien. Darüber hinaus zeigte eine der aktivsten Verbindungen eine bemerkenswerte Selektivität für Tumorzellen gegenüber normalen Zellen.

Gold-Catalyzed Formal [4+2] Cycloaddition as Access to Antitumor-Active Spirocyclic Oxindoles from Alkynes and Isatin-Derived Ketimines.

Due to its excellent bioactivity profile, which is increasingly utilized in pharmaceutical and synthetic chemistry, spirooxindole is an important core scaffold. We herein describe an efficient method for the construction of highly functionalized new spirooxindolocarbamates via a gold-catalyzed cycloaddition reaction of terminal alkynes or ynamides with isatin-derived ketimines. This protocol has a good functional group compatibility, uses readily available starting materials, mild reaction conditions, low catalyst loadings and no additives. It enables the transformation of various functionalized alkyne groups into cyclic carbamates. Gram-scale synthesis was achieved and DFT calculations verify the feasibility of the mechanistic proposal. Some of the target products exhibit good to excellent antiproliferative activity on human tumor cell lines. In addition, one of the most active compounds displayed a remarkable selectivity towards tumor cells over normal ones.

Assembly drives regioselective azide-alkyne cycloaddition reaction

Azide-alkyne cycloaddition reaction is a very common organic reaction to synthesize nitrogen-containing heterocycles. Once catalyzed by Cu(I) or Ru(II), it turns out to be a click reaction and thus is widely applied in chemical biology for labeling. However, besides their poor regioselectivity towards this reaction, these metal ions are not biologically friendly. Hence, it is an urgent need to develop a metal-free azide–alkyne cycloaddition reaction for biomedical applications. In this work, we found that, in the absence of metal ions, supramolecular self-assembly in an aqueous solution could realize this reaction with excellent regioselectivity. Nap-Phe-Phe-Lys(azido)-OH firstly self-assembled into nanofibers. Then, Nap-Phe-Phe-Gly(alkynyl)-OH at equivalent concentration approached to react with the assembly to yield the cycloaddition product Nap-Phe-Phe-Lys(triazole)-Gly-Phe-Phe-Nap to form nanoribbons. Due to space confinement effect, the product was obtained with excellent regioselectivity. Employing the excellent properties of supramolecular self-assembly, we are applying this strategy to realize more reactions without metal ion catalysis.

Synthesis and characterization a new polyoxomolybdate C34H114Fe2Mo12N18Na2O66 and study of its catalytic activity in the production of 1,2,3-triazoles

A new polyoxomolybdate, [(C6H12N4-CH3)2Na2(H2O)8](C6H12N4-CH3)2[(H0.5)N(CH2O)3FeMo6O18.5(OH)2.5]2·10H2O (1), was synthesized. The structure of the synthesized polyoxomolybdate was investigated by single-crystal X-ray diffraction analysis and several other identification techniques such as FTIR and EDX analysis. Each unit cell of 1 contains one cation [(C6H12N4-CH3)2Na2(H2O)8]4+ and two hexamethylenetetramine cations (C6H12N4-CH3)+, and two polyanions [(H0.5)N(CH2O)3FeMo6O18.5(OH)2.5]3– with ten water molecules in the crystal lattice. In the polyanion, molybdenum ions are bonded to two terminal oxygen atoms and two μ2- (Mo-Mo) and μ3- (Mo-Fe-Mo) bridging oxygen atoms. Iron in the center of the polyanion 1 is also surrounded by three deprotonated oxygens of trimethanolamine ligand and three μ3- (Mo-Fe-Mo) bridging oxygen atoms. This new polyoxomolybdate was used as an efficient catalyst in the azide–alkyne cycloaddition reaction to produce various 1,2,3-triazoles with high yields. Additional investigations reveal this catalytic system can be refreshed and utilized for up to six successive applications.