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C Jaime

Publications and source records attributed to C Jaime.

6 recordsLinked to original sources
PubMed2001

Effect of beta-cyclodextrin on the hydrolysis of trifluoroacetate esters.

The hydrolysis of p-F, p-Cl, and m-Cl phenyl trifluoracetates was studied in the presence of beta-cyclodextrin (beta-CD). The reactions are inhibited by beta-CD at pH 6 while they are catalyzed in alkaline solution. MM3 calculations reproduce some of the experimental results. The substrates form inclusion complexes with beta-CD which are of similar stability as those of the corresponding acetates; however, the association of the transition state is less favorable in these reactions than in those of the acetates, and consequently less stronger catalysis is observed.

Journal Article↗
PubMed2001

alpha-, beta-, and gamma-Cyclodextrin dimers. Molecular modeling studies by molecular mechanics and molecular dynamics simulations.

The alpha-, beta-, and gamma-cyclodextrin (CyD) dimers have been studied by molecular mechanics (MM) and molecular dynamics (MD) calculations, and the relative stability of dimers and the involved molecular interactions have been determined. Three possible orientations were considered for the alpha-, beta-, and gamma-CyD dimers: the head-to-head, the head-to-tail, and the tail-to-tail. In vacuo MM calculations were used to obtain the most stable arrangements, and MD simulations were performed over all energy minima obtained for each dimer. Results from MD always show head-to-head orientation as the most stable as a result of the larger number of intermolecular hydrogen bonds present.

Journal Article↗
PubMed2001

Molecular recognition by beta-cyclodextrin derivatives: FEP vs MM/PBSA study.

The complexation of p-tert-butylphenyl p-tert-butylbenzoate, N-(p-tert-butylphenyl)-p-tert-butylbenzamide and a bisadamantyl-phosphate derivative with a beta-cyclodextrin derivative formed by two cyclodextrin units linked by a disulfide bridge on one of the C6 atoms have been studied by computational methods (free energy perturbation (FEP) and Molecular Mechanics/Poisson Bolzmann Surface Area (MM/PBSA)). The calculated relative free energies of the amide and ester are in good agreement with experiment only for MM/PBSA and not for FEP. Only MM/PBSA was applied to the bisadamantyl-phosphate complex and its calculated association free energy was calculated to be similar to that of the ester, which is consistent with the experimental tendencies.

Combinatorial Chemistry Techniques↗
PubMed2000

Complexation between tert-butyl ketones and beta-cyclodextrin. Structural study by NMR and MD simulations

A structural study (NMR and MD) of the complexation between tert-butyl ketones and beta-cyclodextrin has been performed. A priority order for the alkyl and phenyl groups composing the ketones has been determined based on association constants: Ph- > C(6)H(11)- = t-Bu- > Bu-, Pr-, Me-. Geometries for the complexes are proposed based on NOE values and on the MD simulations. Bimodal complexation occurs in all the compounds studied.

Journal Article↗