Chromatography enantioselective liquid

Various techniques used in the investigations include enantioselective liquid chromatography, enantioselective H-NMR spectroscopy, polarimetry, and circular dichroism spectroscopy. This work offers a fundamental new outlook on transition states and on the relationship between the structures of photochromic compounds and the corresponding energy barriers of their ring-opening reactions. 

The resolution of optically active compounds by gas chromatography with chiral phases is a well-established procedure, and the separation of Al-perfluoto-acetylated ammo acid ester enantiomers m 1967 was the first successful application of enantioselective gas-liquid chromatography [39] Ammo acids have been resolved as their A -trifluoroacetyl esters on chiral diamide phases such as N-lauroyl-L-valineferf-butylamideorAl-docosanoyl-L-valme /ez-r-butylamide [40,41,... 

T. A. G. Noctor, Bioanalytical applications of enantioselective high-performance liquid cliromatography in A Practical Approach to Chiral Separations by Liquid Chromatography, Subramanian G (Ed.), VCH, Weinheim, Ch. 12, pp. 357-396 (1994). 

Lamprecht, G., Kraushofer, T., Stoschitzky, K., Lindner, W. (2000). Enantioselective analysis of (R)- and (S)-atenolol I urine samples by a high-performance liquid chromatography column-switching setup. J. Chromatogr. B 740, 219-226. 

Walters, R.R., Buist, S.C. (1998). Improved enantioselective method for the determination of the enantiomers of reboxetine in plasma by solid-phase extraction, chiral derivitization, and column-switching high-performance liquid chromatography with fluorescence detection. J. Chromatogr. A 828, 167-176. 

Selenurane oxides are also one of the hypervalent selenium compounds. Recently, the enantiomers of chiral selenurane oxide 38 were isolated for the first time by enantioselective liquid chromatography of the racemate or by spontaneous resolution occurring during slow evaporation of its acetonitrile solution or slow crystallization from the same solvent.57 The absolute configurations of the enantiomers were determined by X-ray crystallographic analysis (Scheme 17). 

Ye J, Wu J, Liu W (2009) Enantioselective separation and analysis of chiral pesticides by high-performance liquid chromatography. Trends Anal Chem 28 1148-1163... 

S. Allenmark, A. Ohlsson, Enantioselectivity of Lipase-Catalyzed Hydrolysis of Some 2-Chloroethyl 2-Arylpropanoates Studied by Chiral Reversed-Phase Liquid Chromatography , Chirality 1992, 4, 98-102. 

Boonen G, Beck MA, Haberlein H. (1997). Contribution to the quantitative and enantioselective determination of kavalactones by high-performance liquid chromatography on ChiraSpher NT material. J Chromatogr B Biomed Sci Appl. 702(1-2) 240-44. 

A new hydroxynitrile lyase (HNL) was isolated from the seed of Japanese apricot Prunus mume). It accepts benzaldehyde and a large number of unnatural substrates for the addition of HCN to produce the corresponding (7 )-cyanohydrins in excellent optical and chemical yields. A new high-performance liquid chromatography (HPLC)-based enantioselective assay technique was developed for the enzyme, which promotes the addition of KCN to benzaldehyde in a buffered solution (pH 4.0). Asymmetric synthesis of (7 )-cyanohydrins by a new HNL is described (Figure 8.4). ... 

This review provides an overview of the literature published to date on macrocyclic antibiotics exploited for enantioselective separations in high-performance liquid chromatography (HPLC). It was not intended as a comprehensive issue on the applications of such antibiotics in sub- and supercritical fluid chromatography (SFC), thin layer chromatography (TLC), capillary electrophoresis (CE), and capillary electrochromatography (CEC). A number of structural properties of the most important macrocyclic antibiotics applied in HPLC enantioseparations are listed in Table 2.1. 

Bosakova, Z., Cufinovd, E., and Tes ovd, E., Comparison of vancomycin-based stationary phases with different chiral selector coverage for enantioselective separation of selected drugs in high-performance liquid chromatography, J. Chromatogr. A, 1088, 94, 2005. 

Fried, K.M., Koch, P, and Wainer, I.W., Determination of the enantiomers of albuterol in human and canine plasma by enantioselective high-performance liquid chromatography on a teicoplanin-based chiral stationary phase. Chirality, 10, 484, 1998. 

Levin, S., Abu-Lafi, S., The Role of Enantioselective Liquid Chromatography Separations Using Chiral Stationary Phases in Pharmaceutical Analysis, In Advances in Chromatography, Grushka, E. and Brown, P. R., Eds., Vol. 33, Marcel Dekker, New York, pp. 233-266, 1993. 

DK Lloyd, A Ahmed, F Pastore. A quantitative relationship between capacity factor and selector concentration in capillary electrophoresis and high-performance liquid chromatography evidence from the enantioselective resolution of benzoin using human serum albumin as chiral selector. Electrophoresis 18 958-964, 1997. 

Using amylose tris-3,5-dimethylphenylcarbamate as the chiral selector in enantioselective high-performance liquid chromatography, micropreparative resolution of the DHA racemate was achieved and the chromatographic behaviour in enantio-GC could be defined by coinjecting these references of definite chirality (Fig. 17.4) [13]. 

Fig. 17.4 Chromatographic behaviour of dihydroactinidiolide (DHA) enantiomers synthetic racemate (a) DHA fractionation by enantioselective high-performance liquid chromatography (HPLC) (b). Chiral selectors used in enantio-GC DIME-jS-CD (30%) in SE 52 DIAC-jS-CD (30%) in PS 268 DIAC-/1-CD (50%) in OV 1701. Order of elution R (I), S (II) in all cases [13], DIME heptakis(2,3-di-0-methyl), CD cylclodextrin, DIAC heptakis(2,3-di-0-acetyl)...

Separations of enantiomers can be achieved by chiral chromatography. Even, when the enantioselective synthesis of drugs and pharmaceuticals is possible, a major part of chiral compounds is still produced as a racemate and needs to be separated into the enantiomers by chiral high performance liquid chromatography. 

Rosas, M.E., K.L. Preston, D.H. Epstein, E.T. Moolchan, et al., Quantitative determination of the enantiomers of methadone and its metabolite (EDDP) in human saliva by enantioselective liquid chromatography with mass spectrometric detection, J. Chromatogr. B Anal. Technol. Biomed. Life Sci., 796(2), 355-370, 2003. 

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