The enantiomers of N,N-dimethylthiobenzamides: Chromatographic behaviour and rotational barriers

Eiglsperger, A.; Kästner, Fritz; Mannschreck, Albrecht

doi:10.1016/0022-2860(85)80131-9

Cited by 30 publications

(3 citation statements)

References 20 publications

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“…The stochastic method 50 has also been applied to determine reaction rate constants from interconversion peak profiles by Veciana and Crespo, 4 as well as by Mannschreck and coworkers. 3,18,19 Recently, a new computer program (ChromWin), based on both the theoretical plate and the stochastic models was developed by Schurig and coworkers. 7,12,38,43,44 There are, however, only a few experimental and theoretical articles that can confirm the actual abundances of enantiomers R and S in the experiment, or their separate profiles in the interconversion region.…”

Section: Theoreticalmentioning

confidence: 99%

Evaluation of reversible and irreversible models for the determination of the enantiomerization energy barrier for N‐(p‐methoxybenzyl)‐1,3,2‐benzodithiazol‐1‐oxide by supercritical fluid chromatography

et al. 2002

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It has been found that the interconversion of enantiomers on a chromatographic column during the separation process can be studied by the first-order kinetic equations derived both for reversible and irreversible reactions in a stationary system if the extent of interconversion is not too high. The equation derived for irreversible reactions gives, however, results also for higher degrees of enantiomerization while that derived for reversible interconversion failed. The irreversible equation was used to determine the enantiomerization barrier of N-(p-methoxybenzyl)-l,3,2-benzodithiazol-l-oxide enantiomers by supercritical fluid chromatography. The racemate of N-(p-methoxybenzyl)-l,3,2-benzodithiazol-l-oxide was separated by supercritical fluid chromatography on the (R,R)-Whelk-Ol column with supercritical carbon dioxide containing 20% methanol as a mobile phase. Peak areas of enantiomers prior to and after the separation used for the calculation of the enantiomerization barrier were determined by computer-assisted peak deconvolution of peak clusters registered on chromatograms using commercial software.

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Section: Theoreticalmentioning

confidence: 99%

Evaluation of reversible and irreversible models for the determination of the enantiomerization energy barrier for N‐(p‐methoxybenzyl)‐1,3,2‐benzodithiazol‐1‐oxide by supercritical fluid chromatography

et al. 2002

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“…IR (KBr): 3020, 3000 CH3), 1725 (GO), 1600 cm-' (GC). MS (70 eV) m/z (%, fragment): 291(67, M+), 276(100, Mf-CH3), 260 (25,), 244(38,M+ -CH, -CH, -OH). Anal.…”

Section: (Go)mentioning

confidence: 99%

Axially chiral 2‐(dialkylamino)benzamides. Barriers to rotations, determined by NMR and by racemization (neighboring rotor substituents on arene systems, part 3)

Kiefl¹,

Zinner²,

Burgemeister³

et al. 1996

Recl. Trav. Chim. Pays‐Bas

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Abstract. The title compounds (Scheme 1, Y = NMe,) were investigated by variable-temperature NMR and/or by racemization of enantiomers enriched by liquid chromatography on microcrystalline triacetylcellulose. For several reasons, a dialkylamino and a dimethylcarbamoyl group were used, for the first time, as neighboring rotor substituents on a benzene ring. Barriers to rotations about their aryl-nitrogen and/or aryl-carbon bonds were determined and assigned (Table I). Correlated or uncorrelated motions of these groups are possible for amides 11 and 19 bearing in their 3-positions terf-butyl substituents which hinder the aryl-nitrogen rotation. Uncorrelated rotations have been found for amide 15 (Figure 2) and thioamide 8 which have the less voluminous bromine atom in their 3-position.

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“…The reversible interconversion phenomenon has been subject to almost all separation techniques (gas chromatography (GC), high performance liquid chromatography (HPLC) [6][7][8][9], supercritical fluid chromatography [10,11], thin layer chromatography [12,13] and capillary electrophoresis [14][15][16]); the present work will highlight the application of reversible interconversion in GC. Significantly, development of a multitude of enantioselective cyclodextrin phases have permitted an important extension to the study of interconversion processes in complexation GC [17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of reversible interconversion in comprehensive two-dimensional gas chromatography using enantioselective columns in first and second dimensions

Kröger

Wong

Chin

et al. 2015

Journal of Chromatography A

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The enantiomers of N,N-dimethylthiobenzamides: Chromatographic behaviour and rotational barriers

Cited by 30 publications

References 20 publications

Evaluation of reversible and irreversible models for the determination of the enantiomerization energy barrier for N‐(p‐methoxybenzyl)‐1,3,2‐benzodithiazol‐1‐oxide by supercritical fluid chromatography

Evaluation of reversible and irreversible models for the determination of the enantiomerization energy barrier for N‐(p‐methoxybenzyl)‐1,3,2‐benzodithiazol‐1‐oxide by supercritical fluid chromatography

Axially chiral 2‐(dialkylamino)benzamides. Barriers to rotations, determined by NMR and by racemization (neighboring rotor substituents on arene systems, part 3)

Evaluation of reversible interconversion in comprehensive two-dimensional gas chromatography using enantioselective columns in first and second dimensions

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