The binding of alkyl chains to β-cyclodextrin and ‘hydroxypropyl-β-cyclodextrin’

Tee, Oswald S.; Gadosy, Timothy A.; Giorgi, Javier B.

doi:10.1039/p29930001705

Cited by 25 publications

(27 citation statements)

References 14 publications

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“…Analysis of the dependence of k,,, on PI concentration by a method described in detail elsewhere (14,17) allows for the determination of the dissociation constant (Kl) of the CD-PI complex. Values of K, obtained in this way for PIS binding with a-CD and P-CD (14) generally agree well with results in the literature obtained by other methods (14,16,17,20). The K , values for alcohols (Table 1) and alkanesulphonate anions binding to Hp-P-CD were also determined by this method and they are reported elsewhere (16,17).…”

Section: Resultssupporting

confidence: 78%

“…Values of K, obtained in this way for PIS binding with a-CD and P-CD (14) generally agree well with results in the literature obtained by other methods (14,16,17,20). The K , values for alcohols (Table 1) and alkanesulphonate anions binding to Hp-P-CD were also determined by this method and they are reported elsewhere (16,17). For the present study only aliphatic alcohols of three to six carbons were examined as PIS.…”

Section: Resultssupporting

confidence: 78%

“…We interpret the similarity between the slope and intercept term of eqs. [15] and [16] to indicate that the binding of the PI in the initial state and the transition state is similar for the alcohol-mediated cleavage of both esters. Although both sets of data in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The strengths of binding of small molecules containing simple alkyl groups (e.g., alcohols, alkanoate esters, alkanesulphonate ions) to Hp-P-CD are essentially identical to those for binding to P-CD (16,17) but larger compounds may bind to Hp-P-CD much more tightly than to P-CD (18). For example, 1,8-anilinonaphthalenesulphonate ion (1,8-ANS) is bound more tightly to Hp-P-CD than to P-CD by more than an order of magnitude (17).…”

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confidence: 91%

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Spectator catalysis in the cleavage of p-nitrophenyl acetate and p-nitrophenyl hexanoate by "hydroxypropyl-β-cyclodextrin"

Gadosy¹,

Tee²

1996

Can. J. Chem.

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Aliphatic alcohols that form host-guest complexes with "hydroxypropyl-P-cyclodextrin" retard the cleavage of tnnitrophenyl acetate by hydroxypropyl-P-cyclodextrin in basic aqueous solution, due to competitive inhibition. By contrast, these same species do not inhibit the reaction of p-nitrophenyl acetate and p-nitrophenyl hexanoate to the same extent and, in some cases, the addition of alcohols serves to increase the rate of reaction. The observed reaction kinetics require the presence of a process that has one molecule of the "potential inhibitor" in the transition state for ester cleavage. Rate constants, k,, for the reaction of the (ester.hydroxypropy1-P-cyclodextrin) complexes with a series of potential inhibitors show a strong dependence on the ability of the potential inhibitor to bind to the cyclodextrin. On the other hand, rate constants for the kinetically equivalent reaction of the ester with the (cyclodextrin.potential inhibitor) complex show little dependence on the alcohol structure and they vary over a very limited range. The negative logarithms of the apparent dissociation constant of the potential inhibitor from the transition state show a strong dependence on the ability of the potential inhibitor to bind to hydroxypropyl-0-cyclodextrin, indicating that the binding of the potential inhibitor in the initial state and the transition state is similar. It is concluded that the cleavage of p-nitropheny I acetate and p-nitrophenyl hexanoate by hydroxypropyl-P-cyclodextrin in the presence of 14 potential inhibitors can occur with the ester largely outside of the hydroxypropyl-P-cyclodextrin cavity during the transition state, allowing the cavity to be occupied by a molecule of potential inhibitor.Key words: cyclodextrin, spectator catalysis, esterolysis.Resum6 : A cause d'une inhibition compCtitive, les alcools aliphatiques qui forment des complexes h6tes-invitCs avec l'cchydroxypropyl-P-cyclodextrinen retardent le clivage de I'acCtate de tn-nitrophknyle par l'hydroxypropyl-P-cyclodextrine en solution basique aqueuse. Par opposition, ces m&mes espkces n'inhibent pas la rCaction de I'acCtate de p-nitrophenyle et de I'hexanoate dep-nitrophenyle de la m&me faqon et, dans certains cas, I'addition d'alcools sert mCme i augmenter la vitesse de la reaction. Les rCsultats cinCtiques observCs suggkrent I'existence d'un processus qui comporte urze molCcule d'ccinhibiteur potentiel)) dans 1'Ctat de transition du clivage de l'ester. Les constantes de vitesse, k, pour les rCactions des complexes (ester.hydroxypropy1-P-cyclodextrine] avec une sCrie d'inhibiteurs potentiels montre une forte dCpendance sur I'habilitC de l'inhibiteur potentiel B se lier B la cyclodextrine. Par ailleurs, les constantes de vitesse pour la rCaction cinktiquement Cquivalente de l'ester avec le complexe (cyclodextrine.inhibiteur potentiel) ne prksente qu'une faible dCpendance sur la structure de l'alcool et leurs variations ne sont que trks faibles. Les logarithmes nCgatifs des constantes de dissociations apparentes des inhibiteur...

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Section: Resultssupporting

confidence: 78%

Section: Resultssupporting

confidence: 78%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 91%

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Spectator catalysis in the cleavage of p-nitrophenyl acetate and p-nitrophenyl hexanoate by "hydroxypropyl-β-cyclodextrin"

Gadosy¹,

Tee²

1996

Can. J. Chem.

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“…fact, similar correlations are found for other alkyl derivatives, and in a communication (29) we noted a strong correlation between the pK, values for a collection of 28 aliphatics binding to P-CD and H p -P -C D , with unit slope. With the addition of new results, this correlation can now be extended to 54 derivatives, comprising 18 alcohols, 10 aryl alkanoates, 5 alkanesulfonate ions, 8 amines, and 13 ketone^,^ for which the slope = 1.01 t 0.03, intercept = -0.11 t 0.14, and r = 0.983 (Fig.…”

Section: Discussionsupporting

confidence: 57%

Dissociation constants of host–guest complexes of alkyl-bearing compounds with β-cyclodextrin and "hydroxypropyl-β-cyclodextrin"

Tee¹,

Gadosy²,

Giorgi³

1996

Can. J. Chem.

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Dissociation constants (Kd) of host-guest complexes formed from P-cyclodextrin or "hydroxypropyl-P-cyclodextrin" (P-CD and Hp-P-CD) and several types of aliphatic guests (alcohols, alkanesulfonate ions, alkylamines, and a-amino acids), with up to eight carbons in a chain, are reported. These constants were determined by inhibition kinetics and by a spectrofluorometric displacement method based on competition with 1-anilino-8-naphthalenesulfonate ion as a fluorescent probe. The value of Kd for a particular amine is close to that for the corresponding alcohol. For linear alkyl derivatives, there are strong correlations between pK, (= -log Kd) and the chain length of the guest, with slopes around 0.5, complementing trends that were noted earlier. Furthermore, the strengths of binding of various aliphatic derivatives to P-CD and to Hp-P-CD are close, with Kd values for the two CDs usually being within a factor of 2 of each other. Overall, for the binding of over 50 alkyl-bearing derivatives, there is a good correlation of pKd for Hp-P-CD with that for P-CD, with unit slope. These observations imply that the binding of simple aliphatic guests to Hp-P-CD is not greatly influenced by the modification of the hydroxyl groups on the primary side of the P-CD cavity but this may not be true for longer aliphatic derivatives (>Cx) or for aromatics that penetrate farther into the CD cavity.

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Synthesis, Conformation, and Binding Properties of Cyclodextrin Homo- and Heterodimers Connected through Their Secondary Sides

et al. 1998

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The synthesis of homo-and heterocyclodextrin (CD) dimers, containing two CD moieties that are linked through their secondary sides by aliphatic or 2,2'-bipyridyl spacers is described. In these dimers, the glucose units to which the spacers are linked have been transformed into altrose units. The dimers with an octamethylene spacer show self-complexation of the spacer in one of the CD moieties in aqueous solution, as revealed by 1 H and 13 C NMR spectroscopy. Using high-resolution (600 and 800 MHz) NMR spectroscopy and a variety of 2D NMR techniques, an assignment of nearly all of the 1 H NMR signals of two of the CD dimers was made, affording detailed information about the structure of these compounds in water. The self-inclusion of the spacers leads to lower binding affinities for ditopic guest molecules like p-toluidino-6-naphthalene sulfonate (TNS) derivatives and porphyrins. When a rigid 2,2'-bipyridyl group is used to connect the two CD moieties, self-inclusion of the spacer is not possible. This results in the formation of different complexes with ditopic guest molecules, for example, a 2:2 complex with a porphyrin. The CD heterodimers described in this paper contain an a-CD and a b-CD moiety. These dimers display site-specific binding of guest molecules.

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The binding of alkyl chains to β-cyclodextrin and ‘hydroxypropyl-β-cyclodextrin’

Cited by 25 publications

References 14 publications

Spectator catalysis in the cleavage of p-nitrophenyl acetate and p-nitrophenyl hexanoate by "hydroxypropyl-β-cyclodextrin"

Spectator catalysis in the cleavage of p-nitrophenyl acetate and p-nitrophenyl hexanoate by "hydroxypropyl-β-cyclodextrin"

Dissociation constants of host–guest complexes of alkyl-bearing compounds with β-cyclodextrin and "hydroxypropyl-β-cyclodextrin"

Synthesis, Conformation, and Binding Properties of Cyclodextrin Homo- and Heterodimers Connected through Their Secondary Sides

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