Determination of the Enantiomerization Barrier of Arylnaphthalene Lignans by Cryogenic Subcritical Fluid Chromatography and Computer Simulation

Wolf, Christian; Pirkle, William H.; Welch, Christopher J.; Hochmuth, Detlev H.; König, Wilfried Α.; Chee, Gaik‐Lean; Charlton, James L.

doi:10.1021/jo9623705

Cited by 63 publications

(36 citation statements)

References 19 publications

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“…Electronaccepting groups were found to exhibit the opposite behavior. Jung et al 62 evaluated chromatograms of 2,2Ј-disopropylbiphenyl 16 with the program SIMUL and compared the data with the polarimetric measurements of Wolf et al 11 The determined barrier was in good agreement with the values obtained by polarimetry. Hochmuth and König 59 determined the rotational energy barrier of substituted planar-chiral dioxa[n]paracyclophanes, e.g., 17.…”

Section: 47mentioning

confidence: 68%

“…Wolf et al 10,11,58 investigated the influence of substituents on the rotational energy barrier of atropisomeric biphenyls, e.g., 15, 16, by dynamic gas chromatography and polarimetry. They found that electron-donating groups decrease the rotational energy barrier of 2,2Ј-bis(trifluoromethyl)biphenyl 15 derivatives but increase the barrier of 2,2Ј-diisopropylbiphenyl 16 derivatives.…”

Section: 47mentioning

confidence: 99%

“…The influence of the substituents due to electronic or secondary steric effects were negligible. In continuation of their studies, carbocyclic [11]paracyclophanes 18 were synthesized and the rotational energy barrier determined. As expected, the barriers were about 10 kJ/mol lower than found for the dioxa [11]paracyclophanes 17.…”

Section: 47mentioning

confidence: 99%

“…In continuation of their studies, carbocyclic [11]paracyclophanes 18 were synthesized and the rotational energy barrier determined. As expected, the barriers were about 10 kJ/mol lower than found for the dioxa [11]paracyclophanes 17. Trapp and Schurig 9 determined the enantiomerization barrier of Tröger's base 19 on the chiral stationary phase Chirasil-␤-Dex by dynamic chromatography in combination with the stopped-flow multidimensional gas chromatographic technique.…”

Section: 47mentioning

confidence: 99%

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Determination of enantiomerization barriers by dynamic and stopped‐flow chromatographic methods

2001

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In recent years, dynamic chromatography and stopped-flow chromatographic techniques have become versatile tools for the determination of enantiomerization and isomerization barriers. Increasing demands for the stereochemical safety of chiral drugs contributed to the rapid development of new techniques. New computer-aided evaluation systems allow the on-line determination of interconversion barriers from the experimental chromatograms. Both dynamic chromatography and stopped-flow chromatography have been applied to the entire range of chromatographic methods (GC, SFC, HPLC, CE).

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Section: 47mentioning

confidence: 68%

Section: 47mentioning

confidence: 99%

Section: 47mentioning

confidence: 99%

Section: 47mentioning

confidence: 99%

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Determination of enantiomerization barriers by dynamic and stopped‐flow chromatographic methods

2001

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“…If this interconversion takes place within the time of a chromatographic run, it can be followed by chromatography. Techniques such as dynamic gas chromatography (DGC) [545,546], dynamic liquid chromatography (DHPLC) (5,(547)(548)(549)(550) and SFC [551] have been created to investigate such phenomena. Another approach is to use stoppedflow chromatography [550].…”

Section: Enantiomerization Studiesmentioning

confidence: 99%

Chiral separation by chromatographic and electromigration techniques. A Review

Gübitz

Schmid

2001

Biopharm & Drug Disp

226

135

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This review gives a survey of different chiral separation principles and their use in high-performance liquid chromatography (HPLC), gas chromatography (GC), supercritical fluid chromatography (SFC), thin-layer chromatography (TLC), capillary electrophoresis (CE) and capillary electrochromatography (CEC) highlighting new developments and innovative techniques. The mechanisms of the different separation principles are briefly discussed and some selected applications are shown.

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Studies of enantiomerization of chiral 3,4-dihydro-1,2,4-benzothiadiazine 1,1-dioxide type compounds

Cannazza¹,

Braghiroli²,

Tait³

et al. 2001

Chirality

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An on-column HPLC procedure using a chiral stationary phase (CSP) was developed for the determination of rate constants and free energy barriers of enantiomerization of (+/-)IDRA21. Subsequently, the HPLC method was applied for investigation of two structurally related chiral compounds. The individual enantiomers of the studied compounds were isolated in parallel by preparative HPLC and rate constants and free energy barriers of enantiomerization were determined in different solvents. The on-column enantiomerization data revealed that CSP induces different rate constants for the two enantiomers. The results generated off-line were used to determine the influence of solvents on the racemization of (+) and (-) IDRA21 and to gain further insight into the enantiomerization mechanism of chiral 3,4-dihydro-1,2,4-benzothiadiazine 1,1-dioxide type compounds.

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Determination of the Enantiomerization Barrier of Arylnaphthalene Lignans by Cryogenic Subcritical Fluid Chromatography and Computer Simulation

Cited by 63 publications

References 19 publications

Determination of enantiomerization barriers by dynamic and stopped‐flow chromatographic methods

Determination of enantiomerization barriers by dynamic and stopped‐flow chromatographic methods

Chiral separation by chromatographic and electromigration techniques. A Review

Studies of enantiomerization of chiral 3,4-dihydro-1,2,4-benzothiadiazine 1,1-dioxide type compounds

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