• Title/Summary/Keyword: Chiral recognition

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Preparation of Bonded Cellulose Tris(3,5-dimethylphenylcarbamate) Chiral Stationary Phases by Using Three Bifunctional Reagents

  • Zhang, Yi Jun;Huang, Mingxian;Zhang, Yuping;Ryoo, Jae Jeong
    • Bulletin of the Korean Chemical Society
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    • v.34 no.9
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    • pp.2623-2628
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    • 2013
  • Three di-acyl chlolide reagents, adipoyl chloride, terephthaloyl chloride and isophthaloyl chloride, were used as spacer reagents to prepare bonded type of three cellulose (3,5-dimethylphenyl)carbamate (CDMPC) chiral stationary phases (CSPs). The CDMPC CSPs were prepared using these three acid chlorides as spacer agents at the 6-position of the primary hydroxyl group on the glucose unit of cellulose regioselectively. The chiral recognition ability of the prepared CSPs for five racemates was evaluated by normal-phase high-performance liquid chromatography (HPLC) with the following mobile phases: hexane/isopropanol (IPA), hexane/IPA/tetrahydrofuran (THF) and hexane/IPA/chloroform. The result showed that these prepared CSPs can be used in THF and chloroform solutions and the chiral recognition abilities of the CSPs were improved depending on the eluents and chiral samples.

Enantioselective Recognition of Amino Alcohols and Amino Acids by Chiral Binol-Based Aldehydes with Conjugated Rings at the Hydrogen Bonding Donor Sites

  • Kim, Ji-Young;Nandhakumar, Raju;Kim, Kwan-Mook
    • Bulletin of the Korean Chemical Society
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    • v.32 no.4
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    • pp.1263-1267
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    • 2011
  • Novel binol-based uryl and guanidinium receptors having higher ring conjugation at the periphery of the hydrogen bonding donor sites have been synthesized and utilized to study the enantioselective recognition of 1,2-aminoalcohols and chirality conversion of natural amino acids via imine bond formation. There is a remarkable decrease in the stereoselectivites as the conjugation increases at the periphery of hydrogen bonding donor sites. The guanidinium-based receptors show more selectivity towards the amino alcohol than that of the uryl based ones due to its charge reinforced hydrogen bonds. The conversion efficiency of L-amino acids to Damino acids by the uryl-based receptors is higher than that of the guanidinium-based ones.

PHOTOPHYSICAL PROPERTIES OF FLUORENONES WITH CHIRAL SUBSTITUENTS AND THEIR ASYMMETRIC RECOGNITION THROUGH INTERMOLECULAR HYDROGEN BONDING INTERACTIONS IN THE EXCITED STATES

  • Aikawa, Yoshihide;Shimada, Tetsuya;Tachibana, Hiroshi;Inoue, Haruo
    • Journal of Photoscience
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    • v.6 no.4
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    • pp.165-170
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    • 1999
  • Asymmetric recognition of chiral alcohol by fluorenone derivatives with chiral substituents through intermolecular hydrogen bonding interaction in the singlet excited state was attempted. 1-((1S, 2R, 5S)-(+)-Menthyloxycarbonyl)aminofluoren-9-one (1-MAF) and 1-((1S, 2R, 5S)-(+)-menthyloxycarbonyl)oxyfluoren-9-one (1-MOF) were synthesized and their photophysical behaviors were characterized by the measurement of absorption and fluorescence spectra, as well as the quantum yield and the lifetime of fluorescence. The excited singlet states of 1-MAF and 1-MOF were revealed to have characteristics similar to those of fluorenone, though the intramolecular CT nature was fairly suppressed as compared with 3- and 4-substituted aminofluorenones. Fluorescences of 1-MAF and 1-MOF in acetonitrile were quenched by the addition of alcohols. Differences in fluorescence quenching efficiency were hardly observe for rather small chiral alcohols such as (R)-(-)- or (S)-(+)-2-butanol, while bulky alcohols such as menthol and isopinocampheol showed chiral recognition effects in their fluorescence quenching of 1-MAF in either acetonitrile or butyronitrile.

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Chiral discrimination studies of (+)-(18-crown-6)-2.3.11.12-tetracarboxylic acid by NMR spectroscopy

  • Lee, Won-Jae;Baek, Chae;Bang, Eun-Jung
    • Proceedings of the PSK Conference
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    • 2002.10a
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    • pp.399.1-399.1
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    • 2002
  • The chiral stationary phase derived from (+) (18-crown-6)-2.3, 11.12-tetracarboxylic acid (18-C-6- TA) as a chiral selector has been employed for resolution of several $\alpha$-amino acids in HPLC. In a quest for the origin of chiral recognition of $\alpha$-amino acids in the presence of 18-C-6- T, A, as a chiral selector, these interactions responsible for the differential affinities shown toward enantioners were investigated by NNR spectroscopy. (omitted)

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Development and Application of Crown Ether-based HPLC Chiral Stationary Phases

  • Hyun, Myung-Ho
    • Bulletin of the Korean Chemical Society
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    • v.26 no.8
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    • pp.1153-1163
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    • 2005
  • Crown ether-based HPLC chiral stationary phases (CSPs) have been successfully utilized in the resolution of various racemic compounds containing a primary amino group. Especially, CSPs based on chiral crown ethers incorporating chiral binaphthyl unit or tartaric acid unit and based on phenolic pseudo chiral crown ethers have shown high chiral recognition efficiency. In this account paper, a review on the development of crown etherbased HPLC CSPs, their structural characteristics and applications to the resolution of racemic compounds including chiral drugs containing a primary or secondary amino group with the variation of the type and the content of mobile phase components and with the variation of the column temperature is presented.

Molecular Modeling of the Chiral Recognition of Propranolol Enantiomers by a β-Cyclodextrin

  • Kim, Hyun-myung;Jeong, Karp-joo;Lee, Sang-san;Jung, Seun-ho
    • Bulletin of the Korean Chemical Society
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    • v.24 no.1
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    • pp.95-98
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    • 2003
  • Enantioselectivity of the propranolol on β-cyclodextrin was simulated by molecular modeling. Monte Carlo (MC) docking and molecular dynamics (MD) simulations were applied to investigate the molecular mechanism of enantioselective difference of both enantiomeric complexes. An energetic analysis of MC docking simulations coupled to the MD simulations successfully explains the experimental elution order of propranolol enantiomers. Molecular dynamics simulations indicate that average energy difference between the enantiomeric complexes, frequently used as a measure of chiral recognition, depends on the length of the simulation time. We found that, only in case of much longer MD simulations, noticeable chiral separation was observed.