The Stabilization of Transition States by Cyclodextrins and other Catalysts

Tee, Oswald S.

doi:10.1016/s0065-3160(08)60075-1

Cited by 40 publications

(39 citation statements)

References 184 publications

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“…For instance, the results found in the literature for the α-CD are contradictory. Indeed, the works of Komiyama [104], Tee [105], and Spies et al [106] suggested that α-CD cannot interact with DNA because the cavity of this molecule is too small to accommodate DNA base pairs. All these results support the work of Hoffmann and Bock who examined the complex formation between different CDs and nucleotides [107].…”

Section: Iv) Complexation Of Nucleic Acidsmentioning

confidence: 99%

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

Leclercq¹

2016

Beilstein J. Org. Chem.

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In the field of host–guest chemistry, some of the most widely used hosts are probably cyclodextrins (CDs). As CDs are able to increase the water solubility of numerous drugs by inclusion into their hydrophobic cavity, they have been widespread used to develop numerous pharmaceutical formulations. Nevertheless, CDs are also able to interact with endogenous substances that originate from an organism, tissue or cell. These interactions can be useful for a vast array of topics including cholesterol manipulation, treatment of Alzheimer’s disease, control of pathogens, etc. In addition, the use of natural CDs offers the great advantage of avoiding or reducing the use of common petroleum-sourced drugs. In this paper, the general features and applications of CDs have been reviewed as well as their interactions with isolated biomolecules leading to the formation of inclusion or exclusion complexes. Finally, some potential medical applications are highlighted throughout several examples.

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Section: Iv) Complexation Of Nucleic Acidsmentioning

confidence: 99%

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

Leclercq¹

2016

Beilstein J. Org. Chem.

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“…It is well known that S N Ar reactions proceed through a stepwise mechanism in which the rate-determining step is dependent on reaction conditions (e.g., reaction medium, type of nucleophile, and leaving group). 19,[22][23][24][25][26][27][28][29][30] We have recently shown that the S N Ar reaction of 1a with a series of cyclic secondary amines in MeCN proceeds through a stepwise mechanism with a Meisenheimer complex, which decomposes to the products in the rate-determining step via competitive catalytic and uncatalytic routes. 22a In contrast, we have reported that S N Ar reactions of 1-(Y-substituted-phenoxy)-2, 4-dinitrobenzenes (Y = 4-NO 2 , 4-CN, 4-COMe, 4-CHO, 3-Cl, 4-Cl, H and 4-Me) with OH − proceed via a stepwise mechanism with formation of a Meisenheimer complex being the rate-determining step on the basis of the kinetic results that (i) the Brønsted-type plot is linear with ␤ lg = −0.16 and (ii) o constants result in a much better Hammett correlation than − constants.…”

Section: Deduction Of Reaction Mechanismmentioning

confidence: 99%

The α-effect in the S_NAr reaction of 1-(4-nitrophenoxy)-2,4-dinitrobenzene with anionic nucleophiles: effects of solvation and polarizability on the α-effect

Kim

Cho

et al. 2015

Can. J. Chem.

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A kinetic study on S N Ar reactions of 1-(4-nitrophenoxy)-2,4-dinitrobenzene (1a) with various anionic nucleophiles in 80 mol% water -20 mol% DMSO at 25.0°C is reported. The Brønsted-type plot for the reaction of 1a with a series of substituted phenoxides and HOO − results in an excellent linear correlation with ␤ nuc = 1.17. However, OH − exhibits dramatic negative deviation from the Brønsted-type plot, while N 3 − , C 6 H 5 S − , and butane-2,3-dione monoximate (Ox − ) deviate positively from linearity. HOO − is 680-fold more reactive than OH − but does not exhibit the ␣-effect. In contrast, Ox − is 166-fold more reactive than isobasic 4-Cl − C 6 H 4 O − and exhibits the ␣-effect. Differential solvation effects have been suggested to be responsible for the ␣-effect in this study, i.e., Ox − exhibits the ␣-effect, since it is 5.7 kcal/mol less strongly solvated than 4-Cl − C 6 H 4 O − in the reaction medium, while HOO − does not show the ␣-effect due to a strong requirement for partial desolvation before nucleophilic attack. The highly enhanced reactivity of polarizable N 3 − and C 6 H 5 S − and extremely decreased reactivity of nonpolarizable OH − are in accord with the hard-soft acid and base principle.Résumé : Nous présentons une étude cinétique des réactions S N Ar entre le 1-(4-nitrophénoxy)-2,4-dinitrobenzène (1a) et divers nucléophiles anioniques dans un mélange constitué d'eau à 80 % molaire et de DMSO à 20 % molaire à une température de 25,0°C. La courbe de type Brønsted pour les réactions du composé 1a avec une série de phénoxydes substitués et avec l'ion HOO − donne lieu à une excellente corrélation linéaire dont le coefficient ␤ nuc = 1,17. Cependant, les ions OH − sont associés à une déviation négative importante de la courbe de type Brønsted, tandis que les ions N 3 − , C 6 H 5 S − et butane-2,3-dionemonoximate (Ox − ) dévient de la linéarité de façon positive. L'ion HOO − est 680 fois plus réactif que l'ion OH − , mais ne montre pas d'effet ␣. À l'inverse, l'ion Ox − est 166 fois plus réactif que l'ion isobasique 4-ClC 6 H 4 O − et présente l'effet ␣. Nous avons proposé des effets de solvatation variables d'un composé à l'autre pour expliquer l'effet ␣ observé dans cette étude, c.-à -d. que l'ion Ox − présente l'effet ␣ parce qu'il est moins fortement solvaté dans le milieu réactionnel que l'ion 4-Cl-C 6 H 4 O − (différence de 5,7 kcal/mol), tandis que l'ion HOO − ne montre pas d'effet ␣ en raison de fortes contraintes à la désolvatation partielle préalable à l'attaque nucléophile. La réactivité fortement accrue des ions polarisables N 3 − et C 6 H 5 S − et la réduction extrême de la réactivité de l'ion non polarisable OH − sont des phénomènes en accord avec le principe de dureté chimique des acides et des bases. [Traduit par la Rédaction]

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“…The effects of cyclodextrins on electron transfer processes have been considered above. The effects of these kinds of receptors on biomimetic reactions have been reviewed [ 99 ] as well as studies of cyclodextrin effects on organic reactions [ 100 , 101 , 102 , 103 , 104 , 105 , 106 ], redox reactions [ 107 , 108 , 109 ], ligand substitution reactions [ 110 ], etc. , in such a way that the effects of this kind of catalyst on practically any type of reaction have been studied.…”

Section: Microheterogeneous Catalysis With Participation Of Groundmentioning

confidence: 99%

Microheterogeneous Catalysis

2010

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The catalytic effect of micelles, polymers (such as DNA, polypeptides) and nanoparticles, saturable receptors (cyclodextrins and calixarenes) and more complex systems (mixing some of the above mentioned catalysts) have been reviewed. In these microheterogeneous systems the observed changes in the rate constants have been rationalized using the Pseudophase Model. This model produces equations that can be derived from the Brönsted equation, which is the basis for a more general formulation of catalytic effects, including electrocatalysis. When, in the catalyzed reaction one of the reactants is in the excited state, the applicability (at least formally) of the Pseudophase Model occurs only in two limiting situations: the lifetime of the fluorophore and the distributions of the quencher and the probe are the main properties that define the different situations.

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The Stabilization of Transition States by Cyclodextrins and other Catalysts

Cited by 40 publications

References 184 publications

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

The α-effect in the S_NAr reaction of 1-(4-nitrophenoxy)-2,4-dinitrobenzene with anionic nucleophiles: effects of solvation and polarizability on the α-effect

Microheterogeneous Catalysis

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The Stabilization of Transition States by Cyclodextrins and other Catalysts

Cited by 40 publications

References 184 publications

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

The α-effect in the SNAr reaction of 1-(4-nitrophenoxy)-2,4-dinitrobenzene with anionic nucleophiles: effects of solvation and polarizability on the α-effect

Microheterogeneous Catalysis

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The α-effect in the S_NAr reaction of 1-(4-nitrophenoxy)-2,4-dinitrobenzene with anionic nucleophiles: effects of solvation and polarizability on the α-effect