The separation of racemic molecules is of crucial significance not only for fundamental research but also for technical application. Enantiomers remain challenging to be separated owing to their identical physical and chemical properties in achiral environments. Chromatographic techniques employing chiral stationary phases (CSPs) have been developed as powerful tools for the chiral analysis and...

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 beta-CD (PMBCD), permethylated gamma-CD, heptakis(2,6-di-O-butyl-3-O-but...

The processes involved in the transformation of non-porous, native polysaccharides to their highly porous equivalents introduce significant molecular complexity and are not yet fully understood. In this paper, we propose that distinct changes in polysaccharide local short-range ordering promotes and directs the formation of meso- and micro-pores, which are investigated here using N2 sorption, F...

The focus of this contribution is a comparative investigation of enantioseparations of 19 Nα-Fmoc proteinogenic amino acids on Quinine-based zwitterionic and anion-exchanger type chiral stationary phases employing hydro-organic and polar-ionic liquid and subcritical fluid chromatographic conditions. Effects of mobile phase composition (including additives, e.g., water, basis and acids) and natu...

Preparative chiral chromatography has recently become a preferred method for rapidly accessing enantiopure compounds in the pharmaceutical industry [1–8]. While preparative chromatographic enantioseparation has been practiced for a number of years by specialized researchers, the current widespread interest in the approach can be attributed in part to advances in equipment and stationary phases,...

The chiral selector 6-azido-2, 3-di(p-chlorophenylcarbamoylated) cellulose was synthesized and further chemically immobilized onto 5-μm amino functionalized spherical porous silica gel. It was used as chiral stationary phase in high-performance liquid chromatography. Thirty racemates were successfully separated into enantiomers in either normal phase mode or reversed-phase mode. Good reproducib...

Amylose derivatives chiral stationary phases (CSPs), some of which are commercially available, are well known for their powerful enantioseparation performance. However, due to the dissolution or swelling properties of amylose derivatives, this type of CSPs prepared by coating method exhibit poor solvent tolerance and stability. In order to overcome the defect as well as maintain the chiral reco...

The HPLC enantiomeric separation of the racemic cularinoid alkaloids N-p-methoxy-1,alpha-dihydroaristoyagonine (1) and 4',5'-demethoxy-1,alpha-dihydroaristoyagonine (2) was accomplished using five chiral stationary phases (CSPs), some of them polysaccharide-derived ones. The molecular size and conjugative effect strongly affect the different enantioselectivity of the compounds 1 and 2 on the va...

Rene Csuk, Anja Kern, and Kristina Mohr Institut für Organische Chemie. Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 2, D-06120 Halle (Saale), Germany Reprint requests to Prof. Dr. R. Csuk. E-mail: [email protected] Z. Naturforsch. 54b, 1463-1468 (1999); received July 9, 1999 Nucleoside Analogues, HPLC A novel class of nucleoside analogues containing adenine, uracil, thym...