Chiral recognition in the resolution of enantiomers by GLC

Koppenhoefer, Bernhard; Bayer, Ernst

doi:10.1007/bf02687727

Cited by 123 publications

(35 citation statements)

References 19 publications

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“…Such a chiral phase is known under the trade name Chirasil-Val ® and is used for the separation of enantiomers by gas chromatography [13,14]. N,O-HFB-tranylcypromine…”

Section: R-x-h + :Y-r'⇄ R-x-h … Y-r'mentioning

confidence: 99%

Chiral Separation for Enantiomeric Determination in the Pharmaceutical Industry

Grinberg¹,

Pan²

2012

Physico-Chemical Methods in Drug Discovery and Development

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“…Such a chiral phase is known under the trade name Chirasil-Val ® and is used for the separation of enantiomers by gas chromatography [13,14]. N,O-HFB-tranylcypromine…”

Section: R-x-h + :Y-r'⇄ R-x-h … Y-r'mentioning

confidence: 99%

Chiral Separation for Enantiomeric Determination in the Pharmaceutical Industry

Grinberg¹,

Pan²

2012

Physico-Chemical Methods in Drug Discovery and Development

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“…Thus, it can be concluded that the elution order of the enantiomers of mandelates and their analogs on CD CSPs in GC is dominantly determined by the enthalpy difference ∆(∆H). [23][24][25] Therefore, it is possible to predict the elution order by calculating the interaction energies of two enantiomers with cyclodextrin using molecular mechanics methods without taking the entropy change ∆(∆S) into account.…”

Section: Thermodynamic Data Of Mandelates and Their Analogs Onmentioning

confidence: 99%

Enantiomer Separation of Mandelates and Their Analogs on Cyclodextrin Derivative Chiral Stationary Phases by Capillary Gc

et al. 2001

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Mandelic acid and α-methoxymandelic acid were purchased from TCI (Japan). 3-Phenyllactates were prepared according to the literature method.14 Ethyl 2-hydroxy-4-phenylbutyrate is the product of asymmetric hydrogenation of ethyl pyruvate on cinchonidine-modified Pt/Al2O3 catalyst, 7 supplied by the State Key Laboratory of Catalysis (China). All other reagents were commercially available.All the α-hydroxycarboxylic acids were esterified with methanol or ethanol and 98% sulfuric acid, according to a previously published procedure. 14 Instruments and proceduresChromatographic separations were performed with a modified GC-1121 capillary gas chromatograph (Shanghai Analytical Instrument Factory, China) equipped with a flame-ionization detector. Both the injector and detector temperatures were maintained at 250˚C. With H2 as the carrier gas, all the separations were performed isothermally with a split ratio of 1:100.Chiral columns were prepared as described earlier. 13 Briefly, fused silica capillary tubes (30 m × 0.25 mm i.d.) deactivated using PEG-20M were coated statically with mixture solutions of the CD derivatives and polysiloxane diluents dissolved in CH2Cl2, and then conditioned at 190˚C for over 4 h. Enantiomer separation of mandelates and their analogs, which are important intermediates in asymmetric synthetic and pharmaceutical chemistry, was investigated by capillary gas chromatography using different cyclodextrin derivative chiral stationary phases (CD CSPs). The used cyclodextrin derivatives included permethylated β-CD (PMBCD),, respectively. Among all the CSPs used, PMBCD and DNTBCD exhibited the broadest and best enantioselectivity for all the racemates investigated. Some thermodynamic parameters were evaluated and an enthalpy-entropy compensation effect was observed in enantiomer separation processes of mandelates and their analogs. Based on thermodynamic data and molecular mechanics calculations, the chiral recognition mechanism of mandelate derivatives on CD CSPs is discussed.

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“…This has been noted for some time in chiral gas chromatography. 24,25 It additionally known that there are both achiral and chiral contributions to retention that can vary with a wide variety of experimental parameters. [26][27][28][29] Accordingly, the column temperature has often been optimized in enantioselective HPLC separations.…”

Section: Introductionmentioning

confidence: 99%

High‐performance liquid chromatographic chiral separation of β²‐homoamino acids

et al. 2008

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Reversed-phase high-performance liquid chromatographic methods were developed for the separation of enantiomers of eleven unnatural beta(2)-homoamino acids on chiral stationary phases containing macrocyclic glycopeptides (teicoplanin-containing Chirobiotic T and T2) or the macrocyclic peptide teicoplanin aglycone (Chirobiotic TAG) as chiral selectors. The effects of the organic modifier, the mobile phase composition, temperature, and the structures of the analytes on the separations were investigated. Separations were carried out at constant mobile phase compositions in temperature range 7-45 degrees C and the changes in enthalpy, Delta(DeltaH(o)), entropy, Delta(DeltaS(o)), and free energy, Delta(DeltaG(o)), were calculated. The -Delta(DeltaG(o)) values obtained on the three columns indicated that Chirobiotic TAG, without sugar units, may promote the interactions of the enantiomers of beta(2)-homoamino acids with branched alkyl or aryl side-chains, whereas for beta(2)-homoamino acids with alkyl side-chains Chirobiotic T and T2 seem to be more favorable. The elution sequence was determined in some cases and was observed to be R < S.

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Chiral recognition in the resolution of enantiomers by GLC

Cited by 123 publications

References 19 publications

Chiral Separation for Enantiomeric Determination in the Pharmaceutical Industry

Chiral Separation for Enantiomeric Determination in the Pharmaceutical Industry

Enantiomer Separation of Mandelates and Their Analogs on Cyclodextrin Derivative Chiral Stationary Phases by Capillary Gc

High‐performance liquid chromatographic chiral separation of β²‐homoamino acids

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Chiral recognition in the resolution of enantiomers by GLC

Cited by 123 publications

References 19 publications

Chiral Separation for Enantiomeric Determination in the Pharmaceutical Industry

Chiral Separation for Enantiomeric Determination in the Pharmaceutical Industry

Enantiomer Separation of Mandelates and Their Analogs on Cyclodextrin Derivative Chiral Stationary Phases by Capillary Gc

High‐performance liquid chromatographic chiral separation of β2‐homoamino acids

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High‐performance liquid chromatographic chiral separation of β²‐homoamino acids