Determination of relative configuration of symmetrical bis-Tröger’s base derivatives

Dolenský, Bohumil; Parchaňský, Václav; Matějka, Pavel; Havlík, Martin; Bouř, Petr; Král, Vladimı́r

doi:10.1016/j.molstruc.2011.04.018

Cited by 7 publications

(4 citation statements)

References 34 publications

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“…for our experiments. Specifically, tryptophan (an amino acid), baclofen (a skeletal muscle relaxant widely used in the treatment of spastic disorder), primaquine (an antimalarial drug), and two Tröger's bases (building blocks of molecular tweezers recently recognized as a potential efficient vehicle applicable for the recognition of bioactive compounds []).…”

Section: Resultsmentioning

confidence: 99%

“…It should be mentioned that the majority of the studied racemates (Fig. ) have been already separated by chiral CE with the only exception of Tröger's base 2, which was analyzed by chiral high‐performance liquid chromatography (HPLC) []. Specifically, tryptophan [] and baclofen [] have been separated utilizing native α‐CD, primaquine [] by a mixture of CMACDs and Tröger's base 1 employing a mixture of highly sulfated‐α‐CDs [].…”

Section: Resultsmentioning

confidence: 99%

“…Hydrochloric acid (30%) (Suprapur, Merck, Germany), 1 mol/L sodium hydroxide (Tripur, Merck), acetonitrile (99.8%, LiChrosolv, Merck), orthophosphoric acid (50%), thiourea, Tröger's base 1, tryptophan, baclofen, primaquine, dimethyl sulfoxide (DMSO), (all Sigma‐Aldrich, Czech Republic), α‐CD (WAKO Chemicals, Germany), and ultrapure water (Milli‐Q grade, Millipore, France) were used. Tröger's base 2 was a kind gift from the group of professor Kral and it was synthesized according a procedure published elsewhere []. 2 I ‐ O ‐, 3 I ‐ O ‐, and 6 I ‐ O ‐CMACDs were synthesized by Zemplen deacetylation of previously described per‐ O ‐acetyl‐2 I ‐ O ‐, 3 I ‐ O ‐, and 6 I ‐ O ‐CMACD by Jindrich's group [], for more details see Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

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Impact of substituent position in monosubstituted α‐cyclodextrins on enantioselectivity in capillary electrophoresis

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Sýkora

et al. 2012

J of Separation Science

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In this study, our three recently synthesized regiospecifically monosubstituted carboxymethyl-α-cyclodextrins (CMACDs) were successfully applied for the enantiomeric separation of several biologically important low-molecular weight compounds by capillary electrophoresis. The enantioselectivity of the individual monosubstituted CMACDs added into the background electrolyte (BGE) was studied and compared with the mixture of three monosubstituted CMACDs and with native α-cyclodextrin at pH of the BGE ranging from 2.5 to 11. Our experiments revealed a significant influence of the position of the carboxymethyl group on the α-cyclodextrin skeleton on the enantioselectivity for all the studied analytes. Interestingly, the least common 3(I)-O regioisomer was revealed as the most effective chiral selector.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Impact of substituent position in monosubstituted α‐cyclodextrins on enantioselectivity in capillary electrophoresis

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Sýkora

et al. 2012

J of Separation Science

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“…Bis‐TBs generally consist of two TBs sharing one aromatic ring. As a consequence of their structure they can exist in syn ‐ or anti ‐diastereoisomeric form …”

Section: Introductionmentioning

confidence: 99%

Enantioseparation of Tröger's Base Derivatives by Capillary Electrophoresis Using Cyclodextrins as Chiral Selectors

et al. 2013

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The enantioseparation of seven Tröger's base derivatives (TBs) was carried out by capillary electrophoresis using α-, β-, and γ-cyclodextrins as chiral selectors and phosphate at 20 mmol/l concentration, pH 2.5, as background electrolyte. The method was optimized with respect to the concentration of chosen chiral selectors (0-50 mmol/l) and the amount of organic solvent (acetonitrile, 0-25 % (v/v)) in the electrolyte. The results indicate that all the studied variables, i.e., type of chiral selector, its concentration, and the amount of the added organic solvent, have a significant impact on the enantioseparation of the studied TBs. The best results for the majority of the separated TBs were obtained utilizing β-cyclodextrin at 5 mmol/l concentration and with various amounts of acetonitrile added ranging from 5 to 15% (v/v) in the background electrolyte. For the two smallest studied TBs, γ-cyclodextrin with 10% (v/v) acetonitrile also provided good resolution.

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Binding energies of five molecular pincers calculated by explicit and implicit solvent models

et al. 2012

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Molecular pincers or tweezers are designed to hold and release the target molecule. Potential applications involve drug distribution in medicine, environment technologies, or microindustrial techniques. Typically, the binding is dominated by van der Waals forces. Modeling of such complexes can significantly enhance their design; yet obtaining accurate complexation energies by theory is difficult. In this study, density functional theory (DFT) computations combined with dielectric continuum solvent model are compared with the potential of mean force approach using umbrella sampling and the weighted histogram analysis method (WHAM) with molecular dynamics (MD) simulations. For DFT, functional and basis set effects are discussed. The computed results are compared to experimental data based on NMR spectroscopic measurements of five synthesized tweezers based on the Tröger's basis. Whereas the DFT computations correctly provided the observed trends in complex stability, they failed to produce realistic magnitudes of complexation energies. Typically, the binding was overestimated by DFT if compared to experiment. The simpler semiempirical PM6-DH2X scheme proposed lately yielded better magnitudes of the binding energies than DFT but not the right order. The MD-WHAM simulations provided the most realistic Gibbs binding energies, although the approximate MD force fields were not able to reproduce completely the ordering of relative stabilities of model complexes found by NMR. Yet the modeling provides interesting insight into the complex geometry and flexibility and appears as a useful tool in the tweezers' design.

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Determination of relative configuration of symmetrical bis-Tröger’s base derivatives

Cited by 7 publications

References 34 publications

Impact of substituent position in monosubstituted α‐cyclodextrins on enantioselectivity in capillary electrophoresis

Impact of substituent position in monosubstituted α‐cyclodextrins on enantioselectivity in capillary electrophoresis

Enantioseparation of Tröger's Base Derivatives by Capillary Electrophoresis Using Cyclodextrins as Chiral Selectors

Binding energies of five molecular pincers calculated by explicit and implicit solvent models

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