Cucurbit[6]uril as a potential catalyst for the acidic decomposition of azidoaminoalkanes

Wieland, Marcel; Mieusset, Jean‐Luc; Brinker, Udo H.

doi:10.1016/j.tetlet.2012.06.016

Cited by 12 publications

(8 citation statements)

References 37 publications

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“…The potential of CBn to control and catalyze chemical reactions through their distinctive inner cavity 4,64,103,125,[157][158][159][160][161][162][163][164][165][166] has been explored to a considerably lesser extent than that of cyclodextrins as alternative macrocycles. [167][168][169][170][171][172][173] Nevertheless, several successful examples of CBn-catalyzed or CBn-promoted unimolecular and bimolecular reactions are nowadays available, and have been previously reviewed by Sivaguru.…”

Section: Catalysis Inside Cbn Cavitiesmentioning

confidence: 99%

Cucurbiturils: from synthesis to high-affinity binding and catalysis

2015

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In the wide area of supramolecular chemistry, cucurbit[n]urils (CBn) present themselves as a young family of molecular containers, able to form stable complexes with various guests, including drug molecules, amino acids and peptides, saccharides, dyes, hydrocarbons, perfluorinated hydrocarbons, and even high molecular weight guests such as proteins (e.g., human insulin). Since the discovery of the first CBn, CB6, the field has seen tremendous growth with respect to the synthesis of new homologues and derivatives, the discovery of record binding affinities of guest molecules in their hydrophobic cavity, and associated applications ranging from sensing to drug delivery. In this review, we discuss in detail the fundamental properties of CBn homologues and their cyclic derivatives with a focus on their synthesis and their applications in catalysis.

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Section: Catalysis Inside Cbn Cavitiesmentioning

confidence: 99%

Cucurbiturils: from synthesis to high-affinity binding and catalysis

2015

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“…c Isolated yields. CB [5], cucurbit [5]uril; CB [6], cucurbit [6]uril; CB [7], cucurbit [7]uril; CB [8], cucurbit [8]uril. may not be formed necessarily, but glycoluril and paraformaldehyde may directly polymerize to produce the most stable product CB [6].…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the addition of salts containing K and Ca as grinding aids will lead to an increase in the yield of CB [5]. Similarly, the addition of salts containing Ba increases the yield of CB [7], and the addition of toluene with host-guest complexation increases the yield of CB [8]. However, irrespective of the template reagent added, CB [6] is still the most important product.…”

Section: Resultsmentioning

confidence: 99%

“…6 Among them, cucurbit [6]uril (CB [6]) and its substituted compounds are the most studied cucurbituril compounds. For example, Wieland et al 7 reported the use of CB [6] as a catalyst in the decomposition of azidoaminoalkanes under acidic conditions. Lima et al 8 found that the use of composite of CB [6] and vanadium oxide as catalyst increased the yield in closed heterogeneous oxidation reactions.…”

Section: Introductionmentioning

confidence: 99%

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Efficient synthesis of cucurbiturils and their derivatives using mechanochemical high-speed ball milling (HSBM)

2020

High Performance Polymers

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Under solid-phase conditions, mechanical ball milling can be used to selectively prepare cucurbit[6]uril (CB[6]) and its derivatives without the use of catalysts and solvents. Using response surface method to determine the optimal conditions for the synthesis of CB[6]. The yield of CB[6] and its derivatives is 75–95%, with a high selectivity of more than 95%. In the synthesis of CB[6] using this method, the amount of acid required is significantly less, no organic solvent is needed, and the preparation of the fully aryl-substituted CB[6] is possible, which is otherwise difficult to be synthesized directly using traditional methods. Mechanical ball milling, thus, is of great significance in the synthesis and research of new cucurbituril supramolecules. Process scale-up experiments show that the yield and selectivity of the various types of cucurbiturils is higher than 95%, because of which they find good industrial applications.

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“…Consequently, CB[7] substantially enhanced the oxidation of Hcy to HSSH. In fact, reactions catalyzed by CB have been reported, and some examples include the formation of oligotriazoles, acidic decomposition of azidoaminoalkanes, and epoxide alcoholysis [ 26 - 28 ]. Moreover, upon the formation of the HSSH-CB[7] complex, the positively charged ammonium group (NH 3 + ) (pKa = 9.44) of HSSH stabilizes the complex through attractive interaction with the carbonyl portal of CB[7], and the carboxylate group of HSSH is located outside the CB[7] cavity owing to electrostatic repulsion between the anionic carboxylate group and the carbonyl oxygen atoms of the CB[7] ( Fig.…”

Section: Discussionmentioning

confidence: 99%

Selective Homocysteine Assay with Cucurbit[7]uril by pH Regulation

Bae

Kim

Jhee

2022

J. Microbiol. Biotechnol.

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We report the effect of pH on the supramolecular complexation of two biothiols, viz., homocysteine (Hcy) and cysteine (Cys), with cucurbit[7]uril (CB[7]). Under basic pH conditions, Cys did not complex with CB[7], whereas Hcy efficiently complexed with CB[7], as confirmed by 1 H NMR spectroscopy and Ellman’s reagent (5,5’-dithio-bis(2-nitrobenzoic acid), DTNB) assay. 1 H NMR and Raman spectroscopic studies revealed that, in the absence of CB[7], Hcy auto-oxidized slowly (~36 h) to homocystine (HSSH) under basic pH conditions. However, the rate of Hcy oxidation increased by up to 150 fold in the presence of CB[7], as suggested by the DTNB assay. Thus, supramolecular complexation under basic pH conditions led to the formation of a HSSH-CB[7] complex, and not Hcy-CB[7]. The results indicate that Hcy is rapidly oxidized to HSSH under the catalysis of CB[7], which acts as a reaction chamber, in basic pH conditions. Our studies suggest that Hcy concentration, a risk factor for cardiovascular disease, can be selectively and more easily quantified by supramolecular complexation with CB [7].

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Cucurbit[6]uril as a potential catalyst for the acidic decomposition of azidoaminoalkanes

Cited by 12 publications

References 37 publications

Cucurbiturils: from synthesis to high-affinity binding and catalysis

Cucurbiturils: from synthesis to high-affinity binding and catalysis

Efficient synthesis of cucurbiturils and their derivatives using mechanochemical high-speed ball milling (HSBM)

Selective Homocysteine Assay with Cucurbit[7]uril by pH Regulation

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