Pharmaceutical applications of a bonded cyclodextrin stationary phase

Abstract

Abstract.Open tubular columns were coated with Chirasil-Dex, a polysiloxane anchored permethylated /3-cyclodextrin stationary phase. A number of chiral separations of pharmaceuticals and agrichemicals are presented to demonstrate the usefulness of this stationary phase in both GC and SFC. Racemates of various amines, amino acids, amino alcohols, carboxylic acids, coumarines, diols, and imides were resolved. To achieve acceptable separation of some enantiomers, a series of derivatives were studied. In many cases, cyclic derivatives and free acids gave the highest enantioselectivity.

Chiral separation of pyrethroic acids with single isomer permethyl monoamino β-cyclodextrin selector

“…In every case, the (±), 1S isomer of pyrethroic acids migrates first, using any chiral selector in CE. Just the opposite has been observed in the GC analysis with Chirasil-Dex [4]. The right choice of the analytical method (CE or GC) offers an exact determination of enantiomer ratios even in the cases of high enantiomer excess offering ªminor peak firstº possibility.…”

“…The 1R-cis and 1R-trans isomers of acids show much more effective insecticidal activity than the other isomers [2]. The large difference in the biological activity of enantiomers requires chiral synthesis [3] and high-resolution chiral analysis with, e.g., GC [4,5], supercritical fluid chromatography (SFC) [6], LC [7,8], or CE [9±11]. The large number of enantiomers makes it difficult to separate every isomer in ester form, therefore the acidic and alcoholic moieties are frequently analyzed separately.…”

Separation of the enantiomers of 2-phenylcyclopropanecarboxylate esters by capillary gas chromatography on derivatized cyclodextrin stationary phases

“…On each CD-based CSP ~ values for L-menthyl ester III were usually larger than for ethyl ester I and n-butyl ester II. This indicates that higher e values can be obtained for L-menthyl derivatives of a compound than for n-alkyl derivatives of the same compound [ 18,23]. One possible implication is that the enantio-differentiation interaction energies between the modified CDs and enantiomers derivatized with L-menthyl have been increased because of the introduction of the new stereogenic centers of the L-menthyl groups.…”

Synthesis, NMR Spectroscopic Characterization and Polysiloxane‐Based Immobilization of the Three Regioisomeric Monooctenylpermethyl‐β‐cyclodextrins and Their Application in Enantioselective GC

“…IϪVI -eicosa-O-methylcyclomaltoheptaose (3) (500 mg, 0.35 mmol), which was prepared by adapting the procedure of Bradshaw and co-workers, [50,52] in anhydrous THF (20 mL) was added dropwise to a stirred mixture of sodium hydride (17 mg, 0.70 mmol, washed with THF) in anhydrous THF (10 mL Figure 6. Gas chromatographic separation of the enantiomers of neomenthol (3,4), menthol (5,6), and isomenthol (7,8) in the presence of the reference standards n-dodecane (1) and n-tridecane (11,12), and 2-ethylhexanoic (13,14) in the presence of the reference standards n-undecane (9) and ndodecane (10) and O-2-Chirasil-β-Dex (bottom) (carrier gas: dihydrogen; for additional gas chromatographic data, see Table 5) …”