• Bulletin of the Korean Chemical Society
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• 제18권10호
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• pp.1085-1089
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• 1997

A new HPLC chiral stationary phase (CSP 3) has been prepared by connecting N-phenyl N-propyl amide of (S)-naproxen to silica gel through the 6-methoxy-2-naphthyl group of (S)-naproxen. The new CSP has been applied in resolving a homologous series of N-(3,5-dinitrobenzoyl)-α-amino acid esters and a homologous series of N-(3,5-dinitrobenzoyl)-α-(4-alkylphenyl)alkylamines. The separation factors, α, for resolving a homologous series of N-(3,5-dinitrobenzoyl)-α-amino esters and a homologous series of N-(3,5-dinitrobenzoyl)-α-(4-alkylphenyl)alkylamines on the new CSP have been found to remain almost constant throughout the wide range of the length of the alkyl substituent of the analytes while those on the previously reported CSPs (CSP 1 and 2) which were prepared by connecting N-phenyl N-propyl amide of (S)-naproxen to silica gel through the N-propyl group increase or decrease continuously. These results are concluded to support the chiral recognition models which utilize the intercalation of the alkyl substituent of the racemic analytes between the adjacent strands of CSP 1 or 2 to rationalize the increasing or decreasing trends of separation factors.

• 약학회지
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• 제32권2호
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• pp.112-116
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• 1988

The resolution of N-trifluoroacetyl (N-TFA) ter-isopropylesters of Ala, Ile, Leu, Val and Phe by gas chromatography on the (S)-5-isobutyl-$N^3$-phenyl-2-thiohydantoin as stationary phase was investigated. The phase was employed at several column temperatures $(140^{\circ}C{\sim}200^{\circ}C)$ and the separation factors were $1.18{\sim}1.45$ range for five amino acid enantiomers. The possible mechanism of chiral recognition was investigated by NMR technique and the association constant$(K_c)$ was calculated as 201.3(r=0.98) for alanyl derivative.

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.3017-3021
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• 2011

Two chiral stationary phases (CSPs) based on (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 bonded covalently to silica gel were applied for the first time to the resolution of racemic vigabatrin and its analogue ${\gamma}$-amino acids and the resolution results were compared to those on the commercially available Crownpak CR(+) based on (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 coated dynamically onto octadecylsilica gel. While vigabatrin was not resolved at all on Crownpak CR(+), it was resolved quite well on the two CSPs. Among four vigabatrin analogue ${\gamma}$-amino acids, only two were resolved on Crownpak CR(+), but three were resolved on the CSP (CSP 1) containing residual silanol groups and all of four were resolved on the CSP (CSP 2) containing residual silanol group-protecting n-octyl groups. The improved lipophilicity in CSP 2 was proposed to be responsible for its superiority to CSP 1 for the resolution of vigabatrin and analogue ${\gamma}$-amino acids. In addition, the composition of aqueous mobile phase was found to affect the chiral recognition behaviors for the resolution of vigabatrin and analogue ${\gamma}$-amino acids on CSP 2.

• Archives of Pharmacal Research
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• 제23권3호
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• pp.230-236
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• 2000

(1'R, 2R)-, (1'R, 2S)-, (1'S, 2R)- and (1'S, 2S)-$\alpha$-hydroxymetoprolol; (2R)- and (2S)-O-des-methylmetoprolol; and (2R)- and (2S)-metoprolol acid are major metabolites of (2R)-and (2S)-metoprolol, $\beta$-adrenergic antagonist. The focus of most chiral separation methods until now has been on determination of the enantiomeric parent drug. However, it is just as important to be able to follow the metabolism of the enantiomers and their possible chiral metabolites. Therefore, for the study of stereoselective metabolism and pharmacokinetics of metoprolol, the chiral separation of the enantiomers of metoprolol and its metabolites has been investigated using four chiral stationary phases, i.e., Chiralcel OD, Chiral-AGP, Cyclobond I and Sumichiral OA-4900 columns. Metoprolol acid was resolved only by Sumichiral OA-4900. Chiralcel OD provided the highest separation factor and resolution value for metoprolol and O-desmethylmetoprolol and partially resolved the four stereoisomers of $\alpha$-hydroxymetoprolol. Diastereomeric $\alpha$-hydroxymetoprolols were resolved using the coupled column chromatographic system of two chiral stationary phases, Sumichiral OA-4900 column and Chiralcel OD column.

• Archives of Pharmacal Research
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• 제21권2호
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• pp.212-216
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• 1998

A coupled achiral-chiral high-performance liquid chromatographic system has been developed for the determination of the enantiomers of salmeterol, S-(+)-salmeterol and R-(-)-salmeterol in urine. THe salmeterol was separated from the interfering components in urine and quantified on the silica column, and the enantiomeric composition was determined on a Sumichiral OA-4700 chiral stationary phase. The two columns were connected by a switching valve equipped with a silica precolumn. The two columns wer connected by a switching valve equipped with a silica precolumn. The precolumn was used to concentrate the salmeterol in the eluent from the achiral column before backflushing onto the chiral phase. The coupled system was validated.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4423-4426
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• 2011

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2493-2496
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• 2011

• Bulletin of the Korean Chemical Society
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• 제10권6호
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• pp.491-495
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• 1989

Resolution of enantiomers of DNS-amino acids has been achieved by a reversed phase liquid chromatography with an addition of a copper(Ⅱ) complex of N-benzyl-L-hydroxyproline to the mobile phase. N-Benzyl-L-hydroxyproline was prepared and used as a chiral ligand of copper(Ⅱ) chelate for the optical resolution. The pH and the concentration of copper(Ⅱ) chelate, organic solvent, and buffer agent in the mobile phase all affect the optical resolutions of dansyl amino acids. The elution orders between D and L-DNS-amino acids were different depending on the structure of the side chain of the amino acids. The retention mechanism for the chiral separation of the dansyl amino acids can be illustrated by the equilibrium of ligand exchange and by hydrophobic interaction with $C_{18}$ stationary phase. The chiral separation can be illustrated with cis and trans effect of the ligand exchange reaction.

• Archives of Pharmacal Research
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• 제12권1호
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• pp.58-61
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• 1989

Studies of selectivity of hydrogen bond formation in chiral solute-solvent systems have been performed by $^1H\;and\;^{13}C$ nuclear magnetic resonance techniques. These data are correlated with the results of gas chromatographic investigations of the same systems. Interactions between the optically active solvent(N-(N-benzoyl-L-amino acid)-anilide) and optically active solute (N-trifluoroacetyl -L-alanyl isopropyl ester) were examined. NMR evidence indicated that hydrogen bonding interaction occurred between two N-H portion and on peptidyl carbonyl portion in stationary phase and solute molecule on three points. The association constants of solvent-solute interaction were calculated and the structure of the diastereomeric association complex between N-(N-benzoyl-L-valyl)-anilide and N-TFA-L-alanyl isopropyl ester was proposed.

• KSBB Journal
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• 제15권6호
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• pp.541-547
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• 2000

Simulated moving bed (SMB) chromatography has been investigated in order to separate chiral compounds for pharmaceutical use. SMB utilizes the principle of true moving bed (TMB) chromatography, and has the advantages of low solvent usage, flexible configuration of columns and hardwares, and high productivity of the chiral compounds over the TMB. Large scale separation of xylene isomers and saccharides has been conducted since 1960s. However, the application of SMB in the fine chemical industries is still in the infant stage. The study of SMB for the chiral compounds production was initiated in the mid 1990s and further researches are actively undergoing. This review summarizes the principle of SMB as well as the chemistry of chiral stationary phase and chiral compounds.