High-performance liquid chromatography optically active

Chromatography. Under certain conditions, even homochiral and het-erochiral self-assemblies can be separated by achiral methods. Thus, chromatography of partially resolved enantiomers can cause depletion or enrichment of enantiomers on achiral stationary phases with an achiral mobile phase. 14C-Labeled nicotine was first resolved into its enantiomers by high-performance liquid chromatography (HPLC) on an achiral stationary phase (Partisil-ODS or -SCX) through coinjection with optically active nicotine (59). This observation was followed by resolution of a number of chiral compounds by chromatography (<50-62) (Scheme 34). When a chiral diamide in 74% ee was separated on a Kieselgel 60... 

Anionic Catalysis Several bulky methacrylates afford highly isotactic, optically active polymers having a single-handed helical structure by asymmetric polymerization. The effective polymerization mechanism is mainly anionic but free-radical catalysis can also lead to helix-sense-selective polymerization. The anionic initiator systems can also be applied for the polymerization of bulky acrylates and acrylamides. The one-handed helical polymethacrylates show an excellent chiral recognition ability when used as a chiral stationary phase for high-performance liquid chromatography (HPLC) [97,98]. 

Moreover, it is possible to lead these compounds into the diastereomeric esters or amides using of optically active acid anhydrides. In this case, the diastereomers with a covalent bond need not always necessarily be a crystalline compound because there are still some other methods left to separate these diastereomers, such as thin layer chromatography, high-performance liquid chromatography, etc. 

Recently, optically active polythiophenes, incorporating as ring substituents chiral selectors such as (R)-(-)- and CS )-(+)-/V-(3,5-dinitrobcnzoyl)-a-phcnylglycinc used in Pirkle-type stationary phases, have been synthesized.167 These may have potential in enantioselective analysis of chiral chemicals using high performance liquid chromatography (HPLC). 

M Tanaka, K Ono, H Hakusui, T Takegoshi, Y Watanabe, M Kanao. Identification of DP-1904 and its ester glucuronide in human urine and determination of their enantiomeric compositions by high-performance liquid chromatography with optical activity and ultraviolet detection. Drug Metab Dispos 18 698, 1990. 

Separation of the various stereoisomers of the nerve agents for analytical purposes became feasible with the advent of optically active coating materials for columns as used in capillary gas chromatography (GC) and in high performance liquid chromatography (HPLC). The complete separation of the four stereoisomers of soman and of the two stereoisomers of sarin with GC on capillary columns is described in Section III. So far, (-1-)- and (-)-VX could not be separated by means of capillary gas chromatography, but HPLC on a so-called Chiralcel OD-H column yields complete separation of the two stereoisomers of this agent. ... 

Substituted 1,3,4-thiadiazines exhibit optical activity. Chiral 1,3,4-thiadiazines can be separated by high-performance liquid chromatography (HPLC) with a chiral stationary phase <1994PHA401, 2005JCH(1075)65>, respectively by nonaqueous capillary electrophoresis <2001JBB155>. 

Oi N, Horiba M, Kitahara H (1981) Gas chromatographic separation of optical isomers of chrysanthemic acid on an optically active stationary phase. Agric Biol Chem 45(6) 1509-1510 Oi N, Kitahara H, Kira R (1990) Enantiomer separation of pyrethroid insecticides by high-performance liquid chromatography with chiral stationary phases. J Chromatogr A 515 441 50... 

We can also use high-performance liquid chromatography (HPLC, see page 436) to separate a racemic mixture, as long as the stationary medium (e.g. the solid that packs the column) is itself optically active. 

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