نتایج جستجو برای: azides
تعداد نتایج: 935 فیلتر نتایج به سال:
An Unusual Formation of 5-Phenyltetrazole in Reaction of Phenylacetylene with Dimethylammonium Azide
It is known that ammonium azides are both effective and convenient azidation agents, which are widely used in the syntheses of tetrazoles in media of aprotic dipolar solvents. However, until the present time, information about using these reagents for the synthesis of the 1,2,3-triazoles has been absent. In this case, alkali metal azides as well as trimethylsilyzide are the best known azidation...
The 1,3-dipolar cycloaddition of azides and activated alkynes has been used for site-selective labeling of biomolecules in vitro and in vivo. While copper catalysis has been widely employed to activate terminal alkynes for [3 + 2] cycloaddition, this method, often termed "click chemistry", is currently incompatible with living systems because of the toxicity of the metal. We recently reported a...
The introduction of matrix techniques to the synthesis and study of reactive organic molecules has substantially extended the range of molecules available for investigation (Ref. 1). It is now increasingly the case that we need new chemical methods to make progress in this area of investigation. Diazocompounds and azides have proved especially useful as starting points for a new style of photoc...
A new, ligand- and solvent-free method for the Huisgen 1,3-dipolar cycloaddition (click reaction) was developed using a planetary ball mill. Besides various alkynes and azides, a propargyl functionalized polymer was converted by mill clicking. Moreover, it was possible to carry out a click polymerization in a ball mill.
Reactions were performed from aryl azides on the one hand, and activated alkenes coming from β-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving β-dicarbonyl compounds have been theoretically studied using DFT me...
Selective functionalization of complex scaffolds is a promising approach to alter the pharmacological profiles of natural products and their derivatives. We report the site-selective azidation of benzylic and aliphatic C-H bonds in complex molecules catalyzed by the combination of Fe(OAc)2 and a PyBox ligand. The same system also catalyzes the trifluoromethyl azidation of olefins to form deriva...
We have shown that CdS and CdSe nanoparticles can act as very efficient and highly chemoselective photocatalysts for the reduction of aromatic azides to aromatic amines. In several cases, the reaction proceeds with quantum yields near 0.5, which approaches the theoretical maximum for a two-electron process. The wide scope of the reaction was confirmed with compounds containing electron withdraw...
The reactions of gallium trichloride with phenyl and deuterio-phenyl azides, as well as with 4-methoxyphenyl azide and deuterium isotopomers, were examined by product analysis, CW EPR spectroscopy and pulsed ENDOR spectroscopy. The products included the corresponding anilines together with 4-aminodiphenylamine type dimers, and polyanilines. Complex CW EPR spectra of the radical cations of the d...
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