- Regioselective reduction of 1h-1,2,3-triazole diesters
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Regioselective reactions can play pivotal roles in synthetic organic chemistry. The reduction of several 1-substituted 1,2,3-triazole 4,5-diesters by sodium borohydride has been found to be regioselective, with the C(5) ester groups being more reactive towards reduction than the C(4) ester groups. The amount of sodium borohydride and reaction time required for reduction varied greatly depending on the N(1)-substituent. The presence of a β-hydroxyl group on the N(1)-substituent was seen to have a rate enhancing effect on the reduction of the C(5) ester group. The regioselective reduction was attributed to the lower electron densities of the C(5) and the C(5) ester carbonyl carbon of the 1,2,3-triazole, which were further lowered in cases involving intramolecular hydrogen bonding.
- Butler, Christopher R.,Bendesky, Justin,Schoffstall, Allen Milton
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- Azide-alkyne cycloadditions in a vortex fluidic device: Enhanced "on water" effects and catalysis in flow
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The Vortex Fluidic Device is a flow reactor that processes reactions in thin films. Running the metal-free azide-alkyne cycloaddition in this reactor revealed a dramatic enhancement of the "on water"effect. For the copper-catalyzed azide-alkyne cycloaddit
- Oksdath-Mansilla, Gabriela,Kucera, Renata L.,Chalker, Justin M.,Raston, Colin L.
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supporting information
p. 659 - 662
(2021/01/29)
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- Visible-Light-Mediated Click Chemistry for Highly Regioselective Azide–Alkyne Cycloaddition by a Photoredox Electron-Transfer Strategy
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Click chemistry focuses on the development of highly selective reactions using simple precursors for the exquisite synthesis of molecules. Undisputedly, the CuI-catalyzed azide–alkyne cycloaddition (CuAAC) is one of the most valuable examples of click chemistry, but it suffers from some limitations as it requires additional reducing agents and ligands as well as cytotoxic copper. Here, we demonstrate a novel strategy for the azide–alkyne cycloaddition reaction that involves a photoredox electron-transfer radical mechanism instead of the traditional metal-catalyzed coordination process. This newly developed photocatalyzed azide–alkyne cycloaddition reaction can be performed under mild conditions at room temperature in the presence of air and visible light and shows good functional group tolerance, excellent atom economy, high yields of up to 99 %, and absolute regioselectivity, affording a variety of 1,4-disubstituted 1,2,3-triazole derivatives, including bioactive molecules and pharmaceuticals. The use of a recyclable photocatalyst, solar energy, and water as solvent makes this photocatalytic system sustainable and environmentally friendly. Moreover, the azide–alkyne cycloaddition reaction could be photocatalyzed in the presence of a metal-free catalyst with excellent regioselectivity, which represents an important development for click chemistry and should find versatile applications in organic synthesis, chemical biology, and materials science.
- Wu, Zheng-Guang,Liao, Xiang-Ji,Yuan, Li,Wang, Yi,Zheng, You-Xuan,Zuo, Jing-Lin,Pan, Yi
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supporting information
p. 5694 - 5700
(2020/04/24)
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- Water as a solvent for Ru-catalyzed click reaction: Highly efficient recyclable catalytic system for triazolocoumarins synthesis
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A new family of Ru (III) complexes has been synthesized, characterized and their catalytic performance has been tested for alkyne–azide cycloaddition (AAC) in water under ultrasonic irradiation conditions. These complexes are found to be effective heterog
- Arafa, Wael Abdelgayed Ahmed,Nayl, Abd El-Aziz Ahmed
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- An efficient and recyclable thiourea-supported copper(i) chloride catalyst for azide-alkyne cycloaddition reactions
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A reaction between two equivalents of bulky thiourea, i.e., 1,3-bis(2,6-dimethylphenyl)thiourea (L) [L = (ArNH)2C = S; Ar = 2,6-Me2C6H3], and CuCl2 or CuCl in THF solvent afforded a bulky thiourea-sta
- Barman, Milan Kr.,Sinha, Ashish Kumar,Nembenna, Sharanappa
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p. 2534 - 2541
(2016/05/19)
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- Metal-Free Intermolecular Azide-Alkyne Cycloaddition Promoted by Glycerol
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Metal-free intermolecular Huisgen cycloadditions using nonactivated internal alkynes have been successfully performed in neat glycerol, both under thermal and microwave dielectric heating. In sharp contrast, no reaction occurs in other protic solvents, su
- Rodríguez-Rodríguez, Marta,Gras, Emmanuel,Pericàs, Miquel A.,G?mez, Montserrat
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supporting information
p. 18706 - 18710
(2016/01/25)
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- Copper malonamide complexes and their use in azide-alkyne cycloaddition reactions
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We report a rare example of the malonamide functionality being used as a ligand in copper catalysis. We have ligated a homologous series of these O,O-chelating architectures to copper, investigated their structure and exploited them in azide-alkyne cycloa
- Bent,Mahon,Webster
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p. 10253 - 10258
(2015/06/08)
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- Iridium-catalyzed intermolecular azide-alkyne cycloaddition of internal thioalkynes under mild conditions
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An iridium-catalyzed azide-alkyne cycloaddition reaction (IrAAC) of electron-rich internal alkynes is described. It is the first efficient intermolecular AAC of internal thioalkynes. The reaction exhibits remarkable features, such as high efficiency and r
- Ding, Shengtao,Jia, Guochen,Sun, Jianwei
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supporting information
p. 1877 - 1880
(2014/03/21)
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- Transient protection of strained alkynes from click reaction via complexation with copper
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A transient protection method of cyclooctynes from a click reaction with an azide through 1:1 complexation with a cationic copper(I) salt is reported. The application of the method to a cyclooctyne bearing a terminal alkyne enabled the selective copper-catalyzed click conjugation with an azide at the terminal alkyne moiety, which made cyclooctyne derivatives readily accessible.
- Yoshida, Suguru,Hatakeyama, Yasutomo,Johmoto, Kohei,Uekusa, Hidehiro,Hosoya, Takamitsu
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supporting information
p. 13590 - 13593
(2015/02/05)
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- An abnormal N-heterocyclic carbene-copper(I) complex in click chemistry
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Herein we report the synthesis of a copper(I) chloro complex using an abnormal N-heterocyclic carbene (aNHC) salt, 1,3-bis(2,6-diisopropylphenyl)-2,4- diphenylimidazolium. The Cu(aNHC) complex efficiently catalyzed Huisgen 1,3-dipolar cycloaddition reacti
- Sau, Samaresh Chandra,Roy, Sudipta Raha,Sen, Tamal K.,Mullangi, Dinesh,Mandal, Swadhin K.
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p. 2982 - 2991
(2014/03/21)
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- Development of a gold-multifaceted catalysis approach to the synthesis of highly substituted pyrroles: Mechanistic insights via Huisgen cycloaddition studies
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A novel gold-catalyzed method for the regioselective synthesis of highly substituted pyrroles directly from oximes and alkynes was developed via independent optimization of two key steps of the process. Importantly, a cationic gold(I) species was shown to activate multiple steps along the reaction pathway and therefore act as a multifaceted catalyst. Initial gold-promoted addition of the oxime oxygen to the activated alkyne afforded the O-vinyloxime in situ. The O-vinyloxime was subsequently transformed into the pyrrole via a gold-catalyzed tautomerization, [3,3]-sigmatropic rearrangement, and cyclodehydration process. Notably, this method provides a functional group handle in the form of an ester at the 3/4-position for further exploitation. The proposed mechanistic pathway is supported by a novel application of the Huisgen cycloaddition click reaction, which was used to probe the relative stability of substituted O-vinyloximes. The intermediacy of N-alkenylhydroxylamine O-vinyl ethers and imino ketones or imino aldehydes along the reaction pathway were determined by high-temperature 1H, 2H{1H}, and 13C{1H} NMR experiments. X-ray crystallographic evidence was used to further support the mechanistic hypothesis.
- Ngwerume, Simbarashe,Lewis, William,Camp, Jason E.
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p. 920 - 934
(2013/04/10)
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- [Cu8(μ8-H){S2P (OEt)2} 6](PF6): A novel catalytic hydride-centered copper cluster for azide-alkyne cycloaddtion
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A hydride-centered dithiophosphate cluster [Cu8(μ 4-H){S2P(OEt)2}6](PF6) (1)] previously developed by us was applied as a new catalyst to the 1,3-dipolar cycloaddition of organic azides and
- Lee, Bo-Han,Wu, Cheng-Chieh,Fang, Xuan,Liu,Zhu, Jia-Liang
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p. 572 - 577
(2013/07/11)
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- Facet-dependent catalytic activity of Cu2O nanocrystals in the one-pot synthesis of 1,2,3-triazoles by multicomponent click reactions
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We report the highly facet-dependent catalytic activity of Cu2O nanocubes, octahedra, and rhombic dodecahedra for the multicomponent direct synthesis of 1,2,3-triazoles from the reaction of alkynes, organic halides, and NaN3. The catalytic activities of clean surfactant-removed Cu 2O nanocrystals with the same total surface area were compared. Rhombic dodecahedral Cu2O nanocrystals bounded by {110} facets were much more catalytically active than Cu2O octahedra exposing {111} facets, whereas Cu2O nanocubes displayed the slowest catalytic activity. The superior catalytic activity of Cu2O rhombic dodecahedra is attributed to the fully exposed surface Cu atoms on the {110} facet. A large series of 1,4-disubstituted 1,2,3-triazoles have been synthesized in excellent yields with high regioselectivity under green conditions by using these rhombic dodecahedral Cu2O catalysts, including the synthesis of rufinamide, an antiepileptic drug, demonstrating the potential of these nanocrystals as promising heterogeneous catalysts for other important coupling reactions.
- Chanda, Kaushik,Rej, Sourav,Huang, Michael H.
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p. 16036 - 16043
(2014/04/03)
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- Preparation, characterization, and reactivity of azido complex containing a Tp(tBuNC)(PPh3)Ru fragment and ruthenium-catalyzed cycloaddition of organic azides with alkynes in organic and aqueous media
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Treatment of the TpRu complex (PPh3)[Ru]-Cl (1, [Ru] = Tp( tBuNC)Ru) with an excess of sodium azide affords the yellow ruthenium azido complex (PPh3)[Ru]-N3 (2). The triazolato complexes (PPh3)[Ru]-N3C2(R)2 (3a, R = Me; 3b, R = Et) are synthesized via [3+2] cycloadditions of 2 with RO 2CC≡CCO2R. Complete characterization of these triazolato complexes elucidates the structures and establishes the N(2)-bonding type of the addition products. Alkylation of 3a with organic bromides causes cleavage of the Ru-N bond and affords 1,4,5-trisubstituted triazoles. Moreover, addition of CS2 to 2 produces thermally unstable thiothiatriazolate (PPh3)[Ru]-N3CS(S) (5), which converts to the isothiocyanate complexes (PPh3)[Ru]-NCS (6) and (tBuNC) [Ru]-NCS (7). Other reagents also react with 2, but the products do not result from [3+2] cycloadditions. Terminal alkynes undergo ligand substitution reactions rather than a [3+2] cycloaddition with 2 in the presence of H 2O to produce the carbonyl complexes (CO)[Ru]-CH2R (8a, R = Ph; 8b, R = 4-CH3Ph) through ruthenium vinylidene intermediates. Reaction of 2 with H-C≡C-CMe2OH in MeOH gives the cationic Fischer carbene complex {(PPh3)[Ru]=C(OMe)-HC=C(Me)2} + (10). In contrast, reaction of H-C≡C-CH2CH 2OH gives rise to the five-membered cyclic oxycarbene complex {(PPh3)[Ru]=C4H6O}+ (11). Several cationic imine complexes {(tBuNC)[Ru]-(NH=CHR′)}+ (12a, R′ = H; 12b, R′ = CH3; 12c, R′ = Ph) are formed by the reaction of RCH2X with 2. If the reaction of 2 with CH3I is carried out at 35 °C for 24 h, (tBuNC)[Ru]-I (13) could be isolated. Preliminary results on the catalytic activity of 2 are also presented. Complex 2 catalyzes cycloaddition of alkynes and benzyl azide to give the triazoles in organic and aqueous medium. The structures of 1, 2, 3a, 7, 8a, 10, 11, 12b, 12c, and 13 have been determined by X-ray diffraction analysis.
- Lo, Yih-Hsing,Wang, Tsang-Hsiu,Lee, Chia-Yi,Feng, Ying-Hsuan
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p. 6887 - 6899
(2012/11/13)
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- Efficient synthesis and in vitro antitubercular activity of 1,2,3-triazoles as inhibitors of Mycobacterium tuberculosis
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Efficient and rapid synthesis of 1,2,3-triazole derivatives has been achieved via Huisgen's 1,3-dipolar cycloaddition between alkyl/arylazides and diethyl/dimethyl acetylenedicarboxylate in excellent yields under solvent-free conditions. The environmentally friendly solvent-free protocol overcomes the limitations associated with the prevailing time-consuming solution phase protocols and affords the triazoles just in 1-3 min. In vitro antitubercular activity of these triazoles was screened against Mycobacterium tuberculosis H37Rv strain. Four of the compounds showed MIC in the range of 1.56-3.13 μg/mL proving their potential activity.
- Shanmugavelan, Poovan,Nagarajan, Sangaraiah,Sathishkumar, Murugan,Ponnuswamy, Alagusundaram,Yogeeswari, Perumal,Sriram, Dharmarajan
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supporting information; experimental part
p. 7273 - 7276
(2012/02/04)
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- Reusable polymer-supported terpyridine copper complex for [3+2] Huisgen cycloaddition in water
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A polymer-supported terpyridine copper(I) complex was prepared and found to promote the Huisgen [3+2] cycloaddition reaction between azides and alkynes in water to give the corresponding triazoles with up to 87% isolated yield. This catalyst was recovered
- Suzuka, Toshimasa,Ooshiro, Kazumasa,Kina, Ken'yu
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experimental part
p. 601 - 610
(2010/09/07)
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- PROCESS FOR THE PREPARATION OF 1,4,5-TRISUBSTITUTED TRIAZOLES AND 3,4,5-TRISUBSTITUTED TRIAZOLES
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The present invention relates to a process for the preparation of 1,4,5- trisubstituted triazoles and 3,4,5-trisubstituted triazoles according to Formulas (Ia) and 5 (Ib), and mesomers and tautomers thereof, wherein a compound according to Formula (II) or Formula (III): is reacted with a compound according to Formula (IV). The process is very useful for the selective and site-specific addition of azide compounds to optionally activated alkynes to form 1,4,5-trisubstuted triazoles and mesomers and tautomers thereof and the application of this process to the covalent functionalisation of biomolecules.
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Page/Page column 31-32
(2008/12/06)
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- Design, synthesis, and biological evaluation of novel tricyclic HIV-1 integrase inhibitors by modification of its pyridine ring
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This communication details both the syntheses and biological evaluation of a novel class of HIV-1 integrase inhibitors. When the quinoline moiety is replaced with the quinoxoline moiety, the antiviral activity is significantly compromised. Similarly, intr
- Metobo, Sammy E.,Jin, Haolun,Tsiang, Manuel,Kim, Choung U.
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p. 3985 - 3988
(2007/10/03)
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- PHOSPHONATE ANALOGS OF HIV INTEGRASE INHIBITOR COMPOUNDS
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Novel HIV integrase inhibitor compounds having at least one phosphonate group, protected intermediates thereof, and methods for inhibition of HIV-integrase are disclosed.
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Page/Page column 539-540
(2010/02/15)
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- PRE-ORGANIZED TRICYCLIC INTEGRASE INHIBITOR COMPOUNDS
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Tricyclic compounds according to the structure below, protected intermediates thereof, and methods for inhibition of HIV-integrase are disclosed. Formula (I). Al and A2 are moieties forming a five, six, or seven membered ring. L is a bond or a linker connecting a ring atom of Ar to N. X is O, S, or substituted nitrogen. Ar is aryl or heteroaryl. Q is N, +NR, or CR4. The aryl carbons may be independently substituted with substituents other than hydrogen. The compounds may include prodrug moieties covalently attached at any site.
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- Photolysis of fused cyclobutatriazolines: An adventitious route to 3,6-Di(2-pyridyl)pyridazonorbornadiene
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Ultraviolet irradiation of the triazolines (18a,b) formed by the high-pressure addition of benzyl azide to dimethyl 3,6-di(2-pyridyl)-4,5-diazatetracyclo[6.4.1.02,3.09,12]tri deca-3,5,7,10-tetraene-10,12-dicarboxylate (16a) and the r
- Margetic,Butler,Warrener
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p. 959 - 963
(2007/10/03)
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- 1,2,3-triazole[4,5-d]pyridazines-II. New derivatives tested on adenosine receptors
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This paper reports the synthesis and biological evaluation towards A1 and A2 adenosine receptors of new 1,2,3-triazole[4,5-d]pyridazines bearing lipophilic substituents in the 1 position. Some 1-benzyl-4-substituted amino derivatives
- Biagi,Giorgi,Livi,Scartoni,Martini,Tacchi,Merlino,Pasero
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p. 175 - 181
(2007/10/02)
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- Generation and Dienophilic Properties of 1-Benzyl-1H-1,2,3-triazolopyridazine-4,7-dione
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1-Benzyl-5,6-dihydro-1H-1,2,3-triazolopyridazine-4,7-dione (1) by oxidation with lead tetraacetate afforded the corresponding triazolopyridazine-4,7-dione 2 as the intermediate, which was trapped with several dienes giving the hetero-Diels-Alder adducts 3 in good yields.The structure of the cycloadduct 3a was determined by X-ray analysis.
- Theocharis, A. B.,Alexandrou, N. E.,Terzis, A.
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p. 1741 - 1744
(2007/10/02)
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- Dipolar Cycloaddition Reactions of Organic Azides with some Acetylenic Compounds
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Phenyl azide 1 and several substituted benzyl azides 2a-o underwent 1,3-dipolar cycloaddition reactions with dimethyl acrtylenedicarboxylate 3, phenylacetylene 4 and ethyl propiolate 5 to afford the triazoles 6-13.The reactions of these azides with ethyl
- Abu-Orabi, Sultan T.,Atfah, M. Adnan,Jibril, Ibrahim,Mari'i, Fakhri M.,Ali, Amer Al-Sheikh
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p. 1461 - 1468
(2007/10/02)
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