A residual silanol group-protecting chiral stationary phase (CSP) based on optically active (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 was successfully applied to the resolution of fluoroquinolone compounds including gemifloxacin mesylate. The chiral recognition ability of the residual silanol group-protecting CSP was generally greater than that of the residual silanol group-containing CSP. From these results, it was concluded that the simple protection of the residual silanol groups of the latter CSP with lipophilic n-octyl groups can improve its chiral recognition ability for the resolution of racemic fluoroquinolone compounds. The chromatographic resolution behaviors were investigated as a function of the content and type of organic and acidic modifiers and the ammonium acetate concentration in aqueous mobile phase and the column temperature. Especially, the addition of ammonium acetate to the mobile phase was found to be a quite effective means of reducing the enantiomer retentions without sacrificing the chiral recognition efficiency of the CSP.
[Show abstract][Hide abstract] ABSTRACT: This paper provides an overview of the applications of crown ethers as buffer additive in capillary electrophoresis. The applications area can be categorized into the separation of inorganic cations; chiral separation and separation of organic compounds include positional isomers. The use of background electrolytes combining cyclodextrins and crown-ethers for both chiral and non-chiral separation is also presented. Applications published up to the year 2009 from each category are summarized.
Current Pharmaceutical Analysis 04/2010; 6(2):101-113. DOI:10.2174/157341210791202618 · 0.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Two diastereomeric chiral stationary phases (CSPs) were applied to the liquid chromatographic resolution of various racemic alpha-amino methyl esters, alpha-amino N,N-diethylamides and alpha-amino N-propylamides. The CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (R,R)-tartaric acid unit as chiral barriers did not show any chiral recognition. In contrast, the CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (S,S)-tartaric acid unit as chiral barriers was found to show excellent chiral recognition especially for the two enantiomers of alpha-amino N-propylamides. Some of alpha-amino methyl esters and alpha-amino N,N-diethylamides were also resolved on the CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (S,S)-tartaric acid unit. From these results it was concluded that the two chiral units composing the diastereomeric CSPs can show "matched" or "mismatched" effect on the chiral recognition according to their absolute stereochemistry.
Bulletin- Korean Chemical Society 06/2010; 31(6):1551-1554. DOI:10.5012/bkcs.2010.31.6.1551 · 0.80 Impact Factor
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