Enantiomeric compounds

Heth G., Nevo E., Ikan R., Weinstein Y., et ai. (1992). Differential olfactory perception of enantiomeric compounds by blind subterranean mole rats (Spalax ehrenbergi). Experientia 48, 897-902. 

Davankov, V. A., Separation of enantiomeric compounds using chiral HPLC systems. A brief review of general principles, advances, and development trends, Chromatographia, 27, 475, 1989. 

Perhaps the biggest increase in the application and development of the MDLC technique since Cortes s book is in life sciences, which accounts for approximately half of this book. One reason for this may be due to the high level of interest in studying the human proteome (proteomics). Proteomics is such a demanding application that the separating power needed to resolve even the normal proteins in the body is so demanding that maximum separation power is needed to provide this capability. Many aspects of separations in proteomics are discussed in Chapters 9-13, 15 and 16. Chapter 14 discusses enantiomeric compound separations by MDLC. 

ANALYSIS OF ENANTIOMERIC COMPOUNDS USING MULTIDIMENSIONAL LIQUID CHROMATOGRAPHY... 

Two enantiomeric compounds with the formula CHXYZ are found. 

The enantiomeric compounds, ent-1, are available from 1 by inversion through sulfonates11 or through (1-lactones.12 Ethyl (S)-3-hydroxybutanoate of 86-95 % ee has... 

Enantiomers have identical chemical and physical properties in the absence of an external chiral influence. This means that 2 and 3 have the same melting point, solubility, chromatographic retention time, infrared spectroscopy (IR), and nuclear magnetic resonance (NMR) spectra. However, there is one property in which chiral compounds differ from achiral compounds and in which enantiomers differ from each other. This property is the direction in which they rotate plane-polarized light, and this is called optical activity or optical rotation. Optical rotation can be interpreted as the outcome of interaction between an enantiomeric compound and polarized light. Thus, enantiomer 3, which rotates plane-polarized light in a clockwise direction, is described as (+)-lactic acid, while enantiomer 2, which has an equal and opposite rotation under the same conditions, is described as (—)-lactic acid. 

RETENTION (hRFli hRmf AND RESOLUTION (a, Rs)h DATA FOR ENANTIOMERIC COMPOUNDS ON MICROCRYSTALLINE CELLULOSE TRIACETATE PLATES WITH SILICA GEL 60 GF254 AS BINDER (TEMPERATURE 25°C)... 

L. Lepri, M. Del Bubba and F. Masi, Reversed-phase planar chromatography of enantiomeric compounds on microcrystalline cellulose triacetate (MCTA). J. Plan. Chromatogr.—Mod. TLC 11 (1997) 108-113. 

Wainer, I. W, HPLC Chiral Stationary Phases for the Stereochemical Resolution of Enantiomeric Compounds, In Drug Stereochemistry Analytical Methods and Pharmacology, 2nd ed., Wainer, I. W., Ed., Dekker, New York, pp.139-181, 1993. 

Enantiomeric compounds differ from one another only in two aspects The chiroptical characteristics (optical rotation) and the speed of their reaction with chiral molecules. The human olfactory organ is also capable of distinguishing chiral molecules. The odor quality and potency of enantiomeric compounds may show considerable differences. Thus, distinct differentiation in odor perception could be observed in the pairs of enantiomeric oxygenated monoterpenoid odorants. " However, the... 

OhloffG, in Schneider D (ed.), Odorous properties of enantiomeric compounds Olfaction and Taste fV, Wissenschaft Verlagsgesellschaft, Stuttgart, Germany, pp. 156-160, 1972. 

PhosphaaIlenes, 33 313-318 enantiomeric compounds, 33 317 from ethinylalkanes, 33 314-315 HOMO and LUMO orbitals, 33 318-319 n orbitals, 33 318... 

The strategy for the synthesis of carba-hexofuranoses and -pentofuranoses is summarized in Scheme 16. Five new carbaanalogues of hexofuranoses were synthesized 74, 73 and the enantiomer a-L-mannofuranose, and the a-L and /3-D-glucofuranoses. The carba-analogues of the 5-deoxyhexofuranoses with a-L- and -D-lyxo-, and a-L-xyZo-configurations, which we have also prepared [98b], have recently been described, either with the same configuration, or as the enantiomeric compound, or as a racemic mixture [86]. Several of the hitherto known compounds were now obtained in a crystalline state... 

The nmr chemical shifts of nuclei of enantiomeric compounds A+ and A are identical in achiral solvents. However, in a chiral solvent (enantiomerically pure) A., and A will be effectively converted to diastereomers as the result... 

The scheme of thermodynamic equilibration, particularly for 3-hydroxyaI-dehydes 75, as described above for FruA catalysis (Scheme 16) can likewise be applied to reactions with RhuA, the enantiomeric enzyme [189,220]. As is to be expected from the complementarity of the stereoselectivities of these enzymes, the corresponding enantiomeric compounds ent-78 are enriched upon equilibration. Owing to the lower diastereoselectivity of the RhuA versus the FruA enzyme, however, the corresponding FucA configurated isomer 85 accumulates more rapidly at the expense of the thermodynamically less favored diastereomer ent-19 (cf. Scheme 18, Sect. 5.2). 

With these coefficients in hand, exploitation of the FTIR spectra of different synthetic mixtures of the labeled and unlabeled enantiomeric compounds is possible. After applying an automated baseline correction to the spectra and correcting the... 

Clark BJ, Separations of enantiomeric compounds by chiral selectors in the mobile or solvent phase, in A Practical Approach to Chiral Separations by Liquid Chromatography, Subramanian G (Ed.), VCH, Weinheim, p. 311 (1994). 

W. Leuchtenberger, M. Karrenbauer, and U. Ploecker, Scale-up of an enzyme membrane reador process for the manufacture of L-enantiomeric compounds, Ann. N.Y. Acad. Sci. USA 1984, 434, 78-86. 

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