Crown ether-tethered cyclodextrins: superiority of the secondary-hydroxy side modification in binding tryptophan

Suzuki, I.; Obata, Kohki; Anzai, Jun Ichi; Ikeda, Hiroshi; Ueno, Akihiko

doi:10.1039/b002195o

Cited by 52 publications

(38 citation statements)

References 30 publications

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“…In contrast, molecule 3 described in this work represents an example where a peptide skeleton is attached to CD via the large rim of CD. Substitution at the secondary site of CD is well-known in non-peptidic systems [30,31] and there are cases where secondary site modification was proved to be advantageous over the primary one [32,33]. Future studies that will compare the interactions taking place in molecule 3 to other molecules bearing the same peptide but attached through the primary site of the CD and/or longer spacers are expected to give a better understanding of the complexation process.…”

Section: Molecular Designmentioning

confidence: 95%

A novel synthetic luteinizing hormone-releasing hormone (LHRH) analogue coupled with modified β-cyclodextrin: Insight into its intramolecular interactions

Kordopati

Tselios

Kellici

et al. 2015

Biochimica et Biophysica Acta (BBA) - General Subjects

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Section: Molecular Designmentioning

confidence: 95%

A novel synthetic luteinizing hormone-releasing hormone (LHRH) analogue coupled with modified β-cyclodextrin: Insight into its intramolecular interactions

Kordopati

Tselios

Kellici

et al. 2015

Biochimica et Biophysica Acta (BBA) - General Subjects

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“…To the best of our knowledge, however, the influence on amino acid recognition of a substituent's position in a cyclodextrin derivative has seldom studied been before. [26] In this context we wish to report here our investigation into the molecular recognition of aliphatic amino acids by several structurally related organoselenium-modified β-cyclodextrins. Our particular interests are in examination of how minor structural differences in the hosts can affect molecular chiral recognition ability.…”

Section: Introductionmentioning

confidence: 99%

“…It is generally believed that secondary hydroxy side-substituted cyclodextrins are superior to the corresponding primary hydroxy side-substituted cyclodextrins. [26] We are also interested in substituent effects of these β-cyclodextrin derivatives on amino acid recognition. From Table 1, however, it can be seen that we were unable to observe significant differences between secondary hydroxy side-substituted hosts (2a, 2b) and primary hydroxy side-substituted hosts (1a, 1b) on molecular binding.…”

mentioning

confidence: 99%

Enantioselective Recognition of Aliphatic Amino Acids by β‐Cyclodextrin Derivatives Bearing Aromatic Organoselenium Moieties on the Primary or Secondary Side

et al. 2003

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Spectrophotometric titrations have been performed in order to determine the stability constants of inclusion complexation of some aliphatic amino acids with four structurally related organoselenium‐modified β‐cyclodextrins: mono(6‐phenylseleno‐6‐deoxy)‐β‐cyclodextrin (1a), mono[6‐(p‐methoxyphenylseleno)‐6‐deoxy]‐β‐cyclodextrin (1b), mono(2‐phenylseleno‐2‐deoxy)‐β‐cyclodextrin (2a), and mono[2‐(p‐methoxyphenylseleno)‐2‐deoxy]‐β‐cyclodextrin (2b). Conformation analysis by circular dichroism and 2D NMR spectroscopic studies revealed that the aryl‐substituted β‐cyclodextrins gave self‐inclusion intramolecular complexes in aqueous solution, while the extent of penetration depended both on the positions and on the structures of substituents. Quantitative investigation on the binding ability of the hosts with amino acids showed that they were able to recognize the size and the shape of guests, affording supramolecular complexes with quite small stability constants ranging from 24 to 355 M−1. The molecular recognition abilities are discussed from the viewpoints of induced‐fitting mechanisms, geometric complementary, and cooperative binding processes. Furthermore, these β‐cyclodextrin derivatives displayed considerable enantioselectivity towards L/D‐amino acid isomers, giving the highest L‐enantioselectivity (up to 8.4) for inclusion complexation between leucine and 2a. The binding modes of L/D‐leucine with 1b were elucidated from NOESY studies and the chiral recognition phenomena were interpreted accordingly. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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“…The chiral discrimination depends on host-guest interaction, hydrophobic interaction, H-bonding, and dipolar interaction between the solute and the two selectors. Additionally, since there is a cap effect [17] exerted by the benzo-crown ether moiety in the two CSPs, and the spacers are connected at the wider torus rim of the b-CD, the two CSPs can provide a special stereochemical interation with the solute to enter the b-CD cavity through the wider torus rim to form a host-guest complex [21]. This enhances the chiral recognition.…”

mentioning

confidence: 99%

“…The 4'-aminobenzo-18-crown-6 in AB18C6-CD-HPS better recognizes amines than the 4'-aminobenzo-15-crown-5 in AB15C5-CD-HPS [17]. The former can exhibit stronger dipolar interaction [17] and host-guest interaction [28] with the amine moiety of a solute than the latter. Accordingly, longer retention and better enantioselectivity can be obtained by the AB18C6-CD-HPS for some aminecontaining solutes.…”

mentioning

confidence: 99%

Enantiomeric Separations in Capillary Electrochromatography with Crown Ether-Capped -Cyclodextrin-Bonded Silica Particles as Chiral Stationary Phase

Gong

Lee

2002

HCA

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Dedicated to Professor Dieter Seebach on the occasion of his 65th birthday Two novel types of crown ether capped b-cyclodextrin (b-CD) bonded silica, namely, 4'-aminobenzo-Xcrown-Y (X 15, 18 and Y 5, 6, resp.) capped [3-(2-O-b-cyclodextrin)-2-hydroxypropoxy] propylsilylappended silica, have been prepared and used as stationary phases in capillary electrochromatography (CEC) to separate chiral compounds. The two stationary phases have a chiral selector with two recognition sites: crown ether and b-CD. They exhibit excellent enantioselectivity in CEC for a wide range of compounds. After inclusion of metal ions (Na or K ) from the running buffer into the crown ether units, the stationary phases become positively charged and can provide extra electrostatic interaction with ionizable solutes and enhance the dipolar interaction with polar neutral solutes. This enhances the host-guest interaction with the solute and improves chiral recognition and enantioselectivity. Due to the cooperation of the anchored b-CD and the crown ether, this kind of crown ether capped b-CD bonded phase shows better enantioselectivity than either b-CD-or crown ether bonded phases only. These new types of stationary phases have good potential for fast chiral separation with CEC.Introduction. ± Separation of enantiomers is one of the most active areas of chromatography [1 ± 3] and is important in various fields [4 ± 6], e.g., natural-product research, stereospecific synthesis, development of chiral drugs in the pharmaceutical industry, and in environmental studies. Chromatographic methods are typically employed for chiral separation, including high-performance liquid chromatography (HPLC) [7], gas chromatography (GC) [8], micellar electrokinetic capillary chromatography (MECC) [9] and, more recently, capillary electrochromatography (CEC) [10]. To improve chiral separation, two approaches can be used: a) optimization of chromatographic conditions, and b) use of new chiral stationary phases (CSPs) or chiral additives in the mobile phase.GC and LC were the first tools to be employed in the separation of enantiomers [4]. However, conventional LC cannot utilize small particles and/or long columns to obtain high efficiencies because of the pressure limitations of normal pumping systems. Although GC usually offers higher efficiencies than LC due to the larger number of available theoretical plates, most chiral compounds of interest have low volatilities. This limits the use of GC for chiral separations [10]. During the last several years, capillary electrophoresis (CE) has become a powerful technique for chiral separations when chiral selectors are added to the running buffers [11]. CEC is a modern liquid chromatography technique combining the high efficiency of CE with the high selectivity usually obtained by HPLC [2]. The mobile phase is transported through a Helvetica Chimica Acta ± Vol. 85 (2002) 3283 capillary containing the stationary phase by means of electro-osmosis instead of pressure. Neutral solutes are separated by partitioning between the...

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Crown ether-tethered cyclodextrins: superiority of the secondary-hydroxy side modification in binding tryptophan

Cited by 52 publications

References 30 publications

A novel synthetic luteinizing hormone-releasing hormone (LHRH) analogue coupled with modified β-cyclodextrin: Insight into its intramolecular interactions

A novel synthetic luteinizing hormone-releasing hormone (LHRH) analogue coupled with modified β-cyclodextrin: Insight into its intramolecular interactions

Enantioselective Recognition of Aliphatic Amino Acids by β‐Cyclodextrin Derivatives Bearing Aromatic Organoselenium Moieties on the Primary or Secondary Side

Enantiomeric Separations in Capillary Electrochromatography with Crown Ether-Capped -Cyclodextrin-Bonded Silica Particles as Chiral Stationary Phase

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