نتایج جستجو برای: alkyne
تعداد نتایج: 2429 فیلتر نتایج به سال:
Click chemistry has become a ubiquitous chemical tool with applications in nearly all areas of modern chemistry, including drug discovery, bioconjugation, and nanoscience. Radiochemistry is no exception, as the canonical Cu(I)-catalyzed azide-alkyne cycloaddition, strain-promoted azide-alkyne cycloaddition, inverse electron demand Diels-Alder reaction, and other types of bioorthogonal click lig...
The synthesis of isomeric, functionalized 4-vinyl-1,2,3-triazole and 5-vinyl-1,2,3-triazole monomers is demonstrated using heterogeneous copper (copper-in-charcoal)-catalyzed azide-alkyne cycloaddition (CuAAC) or homogeneous ruthenium (Ru)-catalyzed azide-alkyne cycloadditions (RuAAC) “click” protocols. These reactions are regiospecific, exclusively forming 1,4and 1,5-disubstituted triazoles as...
A triazole mimic of a DNA phosphodiester linkage has been produced by templated chemical ligation of oligonucleotides functionalized with 5'-azide and 3'-alkyne. The individual azide and alkyne oligonucleotides were synthesized by standard phosphoramidite methods and assembled using a straightforward ligation procedure. This highly efficient chemical equivalent of enzymatic DNA ligation has bee...
The first study on the reaction of C(+)-C-Se(-) 1,3-dipoles with electron-deficient alkenes and alkyne is reported. 2-Arylselenocarbamoylthiazolium inner salts, the unique thiazole carbene-derived C(+)-C-Se(-) 1,3-dipoles, reacted efficiently with methoxycarbonylallenes or dimethyl acetylenedicarboxylate to produce dihydroselenophenes or selenopheno[2,3-b]pyrazines, respectively, in high yields...
In this study, a new type of degradable polyphosphoester-based polymeric nanoparticle, capable of carrying silver cations via interactions with alkyne groups, has been developed as a potentially effective and safe treatment for lung infections. It was found that up to 15% (w/w) silver loading into the nanoparticles could be achieved, consuming most of the pendant alkyne groups along the backbon...
An efficient and generally applicable protocol for palladium-catalyzed oxidative deacetonative coupling of 4-aryl-2-methyl-3-butyn-2-ols with dialkyl H-phosphonates has been developed. This methodology provides a new and practical route to alkynylphosphonates using the inexpensive 4-aryl-2-methyl-3-butyn-2-ols as the alkyne sources. This reaction could also be performed with aryl bromides, 2-me...
The synthesis of nucleoside analogues incorporating 4-(5-pyrimidinyl)-1,2,3-triazole aglycons as expanded purine nucleobase mimics were accessed using the copper-catalyzed azide-alkyne Huisgen cycloaddition between a ribosyl azide and 5-alkynylpyrimidines. Depending on the nature of the alkyne employed, other nucleoside analogues that possess fluorescence or potential metal-binding properties w...
A racemic Au(I)-catalyzed three-component reaction has been developed to prepare cyclic carbamimidates from imines, terminal alkynes, and sulfonylisocyanates. This reaction exploits the carbophilic π-acidity of gold catalysts to first activate an alkyne toward deprotonation and secondly, to activate the internal alkyne generated toward intramolecular O-cyclization. Unlike similar previously rep...
We report that the 2-phosphaethynolate anion (PCO(-)) reacts with propargylamines in the presence of a proton source to afford novel N-derivatized phosphinecarboxamides bearing alkyne functionalities. Deprotonation of these species gives rise to novel five- and six-membered anionic heterocycles resulting from intramolecular nucleophilic attack of the resulting phosphide at the alkyne functional...
A unique cooperative H2 activation reaction by heterobimetallic (NHC)M'-MCp(CO)2 complexes (NHC = N-heterocyclic carbene, M' = Cu or Ag, M = Fe or Ru) has been leveraged to develop a catalytic alkyne semi-hydrogenation transformation. The optimal Ag-Ru catalyst gives high selectivity for converting alkynes to E-alkenes, a rare selectivity mode for reduction reactions with H2. The transformation...
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