نتایج جستجو برای: pyridine catalyzed huisgen cycloaddition
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We report the preparation of [2]rotaxanes containing an electrochemically and optically active osmium(II) bipyridyl macrocyclic component mechanically bonded with cationic pyridinium axles. Such interlocked host systems are demonstrated to recognise and sense anionic guest species as shown by (1)H NMR, luminescence and electrochemical studies. The rotaxanes can be surface assembled on to gold e...
We synthesized C-10 substituted triazolyl artemisinins by the Huisgen cycloaddition reaction between dihydroartemisinins (2) and variously substituted 1, 2, 3-triazoles (8a-8h). The antimalarial activities of 32 novel artemisinin derivatives were screened against a chloroquine-resistant parasite. Among them, triazolyl artemisinins with electron-withdrawing groups showed stronger antimalarial ac...
A new approach to non-covalent peptide-based nanotubular or rod-like structures is presented, whereby the monomeric units are preorganised into a β-strand geometry that templates the formation of an extended and unusual parallel β-sheet rod-like structure. The conformational constraint is introduced by Huisgen cycloaddition to give a triazole-based macrocycle, with the resulting self-assembled ...
Transition-metal-catalyzed [2+2+2] cycloaddition reactions that use two alkynes and a nitrile is the most straightforward and powerful strategy for the construction of multisubstituted pyridines with high atom efficiency. The iron-catalyzed [2+2+2] cycloaddition to form pyridines remains a great challenge in this field, although significant efforts have been made in various catalytic systems (e...
An asymmetric gold(I)-catalyzed [3+2] cycloaddition of propargyl acetals/ketals and aldehydes is reported, which proceeds via stepwise migration-fragmentation of acetals/ketals and cycloaddition of the in situ generated gold-carbenoid intermediate. Various functionalized 2, 5-dihydrofurans were obtained in good yields and high enantioselectivities. Furthermore, an example of the first gold(I) c...
The Huisgen cycloaddition of azides and alkynes, accelerated by target biomolecules, termed "in situ click chemistry," has been successfully exploited to discover highly potent enzyme inhibitors. We have previously reported a specific Serratia marcescens chitinase B (SmChiB)-templated syn-triazole inhibitor generated in situ from an azide-bearing inhibitor and an alkyne fragment. Several in sit...
Microcontact printing (μCP) has developed into a powerful tool to functionalize surfaces with patterned molecular monolayers. μCP can also be used to induce a chemical reaction between a molecular ink and a self-assembled monolayer (SAM) in the nanoscale confinement between stamp and substrate. In this paper, we investigate the Huisgen 1,3-dipolar cycloaddition, the Diels-Alder cycloaddition an...
In this work, we describe synthesis of conjugates of betulinic acid with substituted triazoles prepared via Huisgen 1,3-cycloaddition. All compounds contain free 28-COOH group. Allylic bromination of protected betulinic acid by NBS gave corresponding 30-bromoderivatives, their substitution with sodium azides produced 30-azidoderivatives and these azides were subjected to CuI catalysed Huisgen 1...
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