Copper(I)-doped Wyoming’s montmorillonite for the synthesis of disubstituted 1,2,3-triazoles

A new catalytic system based on copper(I)-doped Wyoming’s montmorillonite was elaborated. This system was studied and was found to catalyze the formation of 1,4-disubstituted 1,2,3-triazoles when starting from azides and alkynes. It was used for the synthesis of a few triazole derivatives to show its usefulness.     

Rapid in situ synthesis of [C]methyl azide and its application in C click-chemistry

We synthesized [¹¹C]methyl azide ([¹¹C]MeA) by reacting [¹¹C]methyl iodide ([¹¹C]MeI) in situ with an azide-donor and used it in the synthesis of ¹¹C-labeled 1,2,3-triazoles. A one-pot click approach comprised the infusion of gaseous [¹¹C]MeI into a mixture of NaN₃, ethynylbenzene, and CuI in water at a temperature of 100 °C yielding the ¹¹C-triazole in radiochemical yields (RCY) of 25%. In a two-step labeling protocol, we synthesized the [¹¹C]MeA in acetonitrile in advance to the click step. Using the more soluble complex as source of , a much higher trapping efficiency of [¹¹C]MeI in this solvent ensured an almost quantitative conversion of [¹¹C]MeI to [¹¹C]MeA within 5-10 min at room temperature. The [¹¹C]MeA was thereafter reacted with ethynylbenzene at 100 °C yielding 1-[¹¹C]methyl-4-phenyl-1H-1,2,3-triazole in preparative RCY of 60%. As a final proof of applicability, we used ¹¹C-click-chemistry for the labeling of N-terminal 4-ethynylbenzene derivatized d-Glu-d-Tyr-[Cys-Tyr-Trp-Lys-Thr-Cys]-Thr, a cyclic water-soluble Tyr³-octreotate derivative.     

Metal-free synthesis of 1,2,3-benzotriazines

The recent molecular iodine catalyzed [1,2]-rearrangement of aryl amines and 3-amino-1H-indazolesfor the synthesis of 1,2,3-benzotriazines is highlighted.     

Efficient synthesis of deuterated 1,2,3-triazoles

A wide variety of 1-monosubstituted 1,2,3-triazoles were synthesized efficiently via a copper-catalyzed click-reaction between azides and acetylene gas, generated in situ from CaC₂ with the addition of H₂O or D₂O.     

DABCO-mediated aza-Michael addition of 4-aryl-1H-1,2,3-triazoles to cycloalkenones. Regioselective synthesis of disubstituted 1,2,3-triazoles

Aza-Michael addition of 4-aryl-1H-1,2,3-triazoles to 2-cycloalken-1-ones has been studied in the presence of DABCO as organic base. The reactions were carried out in acetonitrile at room temperature to provide 2,4-disubstituted 2H-1,2,3-triazoles as major adducts and 1,4-disubstituted 1H-1,2,3-triazoles as minor adducts. Though the reaction times are longer (4–8 days), the two regioisomers were separated by using column chromatography and the adducts were obtained in very good to excellent combined chemical yields. The electron-rich and electron-poor substituents on aryl moiety of 4-aryl-triazoles could tolerate the reaction conditions to afford the title adducts.     

CTAB promoted CuI catalyzed green and economical synthesis of 1,4-disubstituted-1,2,3-triazoles

A practical, straightforward, and highly efficient CuI mediated green protocol for the regioselective synthesis of 1,4-disubstituted-1,2,3-triazole was developed using cetyltrimethylammonium bromide as a cheap additive in good to excellent yields. Low catalyst loadings, environmentally friendly solvent, wide substrate scope and short reaction times at room temperature make this strategy more accessible and safe.     

Direct synthesis of 1,5-disubstituted-4-magnesio-1,2,3-triazoles, revisited

After revisiting earlier works reporting the regioselective synthesis of 1,5-disubstituted-1,2,3-triazoles via the addition of bromomagnesium acetylides to azides, much improved yields of the products were obtained for a wide array of azides and alkynes. The intermediates of that reaction can be trapped with different electrophiles to regioselectively form 1,4,5-trisubstituted 1,2,3-triazoles. [reaction: see text]     

Efficient,mild synthesis of N-unsubstituted 1,2,3-triazoles from methanolysis of 1-sulfonyl-1,2,3-triazoles

A small library of diverse N-unsubstituted 1,2,3-triazoles was prepared from the corresponding 1-sulfonyl-1,2,3-triazoles, which were treated only with MeOH at reflux temperature. This process was carried out in good yields showing high efficiency and good functional group tolerance.     

Efficient TMG catalyzed synthesis of 1,2,3-triazoles

A practical and efficient method for the synthesis of 1,2,3-triazoles via the cycloaddition reaction of azides and CH-acids in the presence of 1,1,3,3-tetramethylguanidine (TMG) in ethanol at 30 °C has been reported. The simple experimental procedure, short reaction times, and good yields are the advantages of the present method.     

Regiospecific solid-phase synthesis of substituted 1,2,3-triazoles

A traceless and regiospecific solid-phase synthesis of substituted 1,2,3-triazoles is developed using polystyrene-sulfonyl hydrazide resin. The chemistry is applicable to combinatorial library synthesis.     

Tandem synthesis of 1-formyl-1,2,3-triazoles

A tandem method for preparing 4-formyl-1,2,3-triazoles via a two-step one-pot acetal cleavage/CuAAC reaction was developed. Using this method, 4-formyl-1,2,3-triazole analogs with both electron-withdrawing and electron-donating substituents were prepared in good yield and purity. Expansion of this method to a three-step tandem reaction that incorporates an additional step of azide substitution was also successful, circumventing the need for organic azide isolation. This one-pot method, noteworthy in its simplicity and mild conditions, utilizes practical, readily available reactants and relies on protic solvent to promote acid-catalyzed acetal cleavage.     

Metal-free synthesis of 1,2,3-benzotriazines

The recent molecular iodine catalyzed [1,2]-rearrangement of aryl amines and 3-amino-1H-indazolesfor the synthesis of 1,2,3-benzotriazines is highlighted.     

A photolabile linker for the solid-phase synthesis of 4-substituted NH-1,2,3-triazoles

This communication presents the synthesis of a novel photolabile azidolinker based on the o-nitroveratryl group. The application of this linker for the synthesis and photolytic release of NH-1,2,3-triazoles is described.     

Simple synthesis of 1-substituted-4-vinyl-1,2,3-triazoles based on polystyrene-supported sulfonyl chloride

Polystyrene-supported but-3-ynyl sulfonate reagent has been developed and applied to the traceless solid-phase organic synthesis of 1-substituted-4-vinyl-1,2,3-triazoles by CuI-promoted 1,3-dipolar cycloaddition reaction with various organic azides and subsequent cleavage from the polymer support through elimination reaction mediated by 1.8-diazabicyclo[5,4,0]undec-7-ene (DBU). The advantages of this new synthetic method include simple operation and moderate to good yields of the products, as well as good stability of the reagent.     

5-卤代1,2,3,-三唑互变异构的密度泛函理论研究

用密度泛函B3LYP/6-311 G**方法,对气相和水相中的1,2,3三,-唑及5-卤(-F、C l和-B r)代1,2,3,-三唑互变异构体进行了几何构型全自由度优化,获得了它们在气相和水相中的几何结构和电子结构。计算结果显示,在气相和水相中1,2,3三-唑和5-卤代1,2,3三-唑的N2-H型要比对应的N1-H型和N3-H型稳定。讨论了不同的取代基团和溶剂化效应对互变异构体的几何结构、能量和电荷分布以及互变异构反应活化能的影响带。并进一步研究了N1-H、N2-H和N3-H型三唑之间的互变异构机理:(a)分子内质子转移;(b)水助质子转移。计算结果表明,途径(b)所需要的活化能较小,为120.06KJ/mol,途径(a)为204.12KJ/mol。     

Reaction of CF3-ynones with azides. An efficient regioselective and metal-free route to 4-trifluoroacetyl-1,2,3-triazoles

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Metal-free and azide-free synthesis of 1,2,3-triazoles derivatives

1,2,3-Triazoles, significant five-membered ring N-heterocycles, are main structural moieties in well-designed materials, pharmaceutical agents, bioactive products, and synthetic intermediates. In the research of life sciences and pharmaceuticals, by seeing the spacious applications of 1,2,3-triazoles, the progress of metal-free method is exceedingly desirable to evade the heterocyclic product metal contamination. Moreover, on a larger scale, the toxicity and explosiveness of azides makes azides discommode and hard to hold, to synthesize 1,2,3-triazoles. The need to steer the development of the synthesis of 1,2,3-triazoles toward more maintainable synthesis is a pressing issue. There are rare methods to construct 1,2,3-triazoles under azide-free and metal-free environments. These rare methods are compiled in this review. The afford of the collection and compilation of azide-free and metal-free synthesis methodologies of 1,2,3-triazole in single podium is supportive and crucial for synthetic chemist to extend the diversity of the synthesis of 1,2,3-trizoles through green protocol.     

Selective synthesis of 1,3-dialkyl-4-nitro-1,2,3-triazolium salts from 1-alkyl-4-nitro-1,2,3-triazoles and dialkyl sulfates

The process of alkylation of 1-alkyl-substituted 4-nitro-1,2,3-triazoles with dimethyl and diethyl sulfates has been studied. The structures of the N,N’-dialkyl-C-nitro-1,2,3-triazolium alkylsulfates and perchlorates has been confirmed by IR, ¹H and ¹³C NMR spectroscopy. Alkylation with an excess of dialkyl sulfate occurred regioselectively at N-3 with the formation of 1,3-dialkyl-4-nitro-1,2,3-triazolium salts, which is in agreement quantum-chemical calculations of the relative stability of the corresponding isomeric cations. The molecular and crystal structures of the first example of this type of salt – 1,3-diethyl-4-nitro-1,2,3-triazolium perchlorate – have been determined by X-ray crystallo-graphy. Nitrotriazolium salts with mixed alkyl substituents – 3-ethyl-1-methyl- and 1-ethyl-3-methyl-4-nitro-1,2,3-triazolium salts – have been synthesized an studied for the first time.     

C-H bond functionalization in the synthesis of fused 1,2,3-triazoles

A highly modular approach to fused 1,2,3-triazoles has been developed featuring a one-pot procedure combining copper(I) catalyzed azide-alkyne cycloaddition and palladium-catalyzed C-H bond functionalization. A class of structurally unique heterocycles was synthesized in good yields.