On the solvent versatility in immobilized amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase in high performance liquid chromatography: Application to the asymmetric cyclopropanation of olefins

Ghanem, Ashraf; Aboul‐Enein, Hassan Y.

doi:10.1016/j.aca.2005.05.079

Cited by 20 publications

(9 citation statements)

References 20 publications

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“…The complete solvent compatibility in normal-phase and polar-organic modes of IA permits us to explore new selectivity profiles and theoretically to enhance chiral separation in terms of resolution degree. 15,16 A series of nonstandard mobile phases containing CH 2 Cl 2 , ethyl acetate (EA), THF, acetone, acetonitrile, and methyltertbutylether (MtBE) were employed in enantioseparation of aptazepine derivatives and Mianserin on the bonded-type Chiralpak IA CSP. Among the unconventional systems used, we report the chromatographic results obtained by the following optimized mobile phases: MtBE-2-propanol-DEA 100-5-0.1 and 95-2-0.1 (for 2a-6a and 1, 2b-6b, respectively), n-hexane-CH 2 Cl2-2-propanol-DEA 50-50-1-0.1 and 75-25-1-0.1 (for 2a-6a and 1,2b-6b, respectively) and n-hexane-EA-2-propanol-DEA 50-50-1.5-0.1 and 95-5-1.5-0.1 (for 2a-6a and 1,2b-6b, respectively).…”

Section: Resultsmentioning

confidence: 99%

Direct HPLC enantioseparation of chiral aptazepine derivatives on coated and immobilized polysaccharide‐based chiral stationary phases

et al. 2006

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The direct HPLC enantioseparation of Mianserin and a series of aptazepine derivatives is accomplished on polysaccharide-based chiral stationary phases (CSPs). The resolutions are performed on the coated-type Chiralcel OD and Chiralpak AD CSPs and on the first commercially available immobilized-type Chiralpak IA CSP, in normal-phase and polar-organic modes. The complete separation of enantiomers of all racemates investigated was successfully achieved under at least one of CSP/eluent combinations employed. Pure alcohols such ethanol or 2-propanol, with a fixed percentage of DEA added, serve as valuable alternatives to the more common n-hexane-based normal-phase eluents in resolution of Mianserin on the AD CSP. In order to study the chiroptical properties of aptazepine derivatives, chromatographic resolutions are carried out at semipreparative scale using Chiralpak AD and Chiralpak IA as CSPs. Nonconventional dichloromethane-based eluents have permitted to expand the chiral resolving ability of the immobilized Chiralpak IA CSP and to perform mg-scale enantioseparations with an analytical-size column. Assignment of the absolute configuration of the separated enantiomers is empirically established by comparing their chiroptical data with those of structurally related Mianserin.

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Section: Resultsmentioning

confidence: 99%

Direct HPLC enantioseparation of chiral aptazepine derivatives on coated and immobilized polysaccharide‐based chiral stationary phases

et al. 2006

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“…To study the solvents versatility and find new selectivity profiles for the new column, several nonstandard solvents known to be harmful for the similar but coated phase Chiralpak AD have been selected depending on their UV cutoff, which should be below the absorbance of the analyte itself. 16,17 Therefore, 100% v dichloromethane (DCM), tetrahydrofuran (THF), or methyl tert-butyl ether (MTBE) were used as mobile phases at different flow rates (0.3, 0.5, and 1 ml/min) and fixed UV detection 254 nm. None of the reported compounds (see Fig.…”

Section: Resultsmentioning

confidence: 99%

Chiral recognition ability and solvent versatility of bonded amylose tris(3,5‐dimethylphenylcarbamate) chiral stationary phase: Enantioselective liquid chromatographic resolution of racemic N‐alkylated barbiturates and thalidomide analogs

Ghanem

Al‐Humaidi

2007

Chirality

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The chiral recognition ability and solvent versatility of a new chiral stationary phase containing amylose 3,5-dimethylphenylcarabamate immobilized onto silica gel (CHIRALPAK IA) is investigated. Thus, the direct enantioselective separation of a set of racemic N-alkylated barbiturates and 3-alkylated analogs of thalidomide was conducted using different nonstandard solvents as eluent and diluent, respectively in high-performance liquid chromatography (HPLC). The separation, resolution, and elution order of the investigated compounds were compared on both immobilized and coated amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phases (Chiralpak IA and Chiralpak AD, respectively) using a mixture of n-hexane/2-propanol (90:10 v/v) as mobile phase with different flow-rates and fixed UV detection at 254 nm. The effect of the immobilization of the amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase on silica (Chiralpak IA) on the chiral recognition ability was noted as the bonded phase (Chiralpak IA) was superior in chiral recognition and possesses a higher resolving power in most of the reported cases than the coated one (Chiralpak AD). A few racemates were not or poorly resolved on the immobilized Chiralpak IA or the coated Chiralpak AD when using standard solvents were most efficiently resolved on the immobilized Chiralpak IA upon using nonstandard solvents. Furthermore, the immobilized phase withstands the nonstandard (prohibited) HPLC solvents such as dichloromethane, ethyl acetate, tetrahydrofuran, methyl-tert-butyl ether, and others when used as eluents or as a dissolving agent for the analyte itself. The direct analysis of a real sample extracted from plasma using DCM on Chiralpak IA is also shown.

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“…A general screening strategy in NPLC mode starts very often with the use of a mobile phase based on n-hexane (can be replaced by the less toxic iso-hexane) or n-heptane since these proved to give the best results on polysaccharide derivative CSPs, regardless of whether the selectors are coated or immobilized on the silica support [37,38,[42][43][44][45][46][47][48][49][50][51][52]. Very often, alcohols such as methanol, ethanol, or 2-propanol are added to the hydrocarbon solvent.…”

Section: Normal-phase Liquid Chromatographymentioning

confidence: 99%

“…The immobilization of the polysaccharide derivatives on the silica support makes it possible to use solvents such as tetrahydrofuran, dichloromethane, and methyl tert-butyl ether, which were forbidden on the coated phases. This enlarges the complementarity between stationary phases [50]. These selectors can in principle be introduced in the same strategies as those for coated CSPs, occasionally with an extension of the organic modifiers used.…”

Section: New Developmentsmentioning

confidence: 99%

High‐Throughput Screening and Method Development Strategies to Separate Chiral Drug Compounds in HPLC, SFC, and CE

Ates

Mangelings

Heyden

2010

Chiral Separation Methods for Pharmaceutical and Biotechnological Products

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On the solvent versatility in immobilized amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase in high performance liquid chromatography: Application to the asymmetric cyclopropanation of olefins

Cited by 20 publications

References 20 publications

Direct HPLC enantioseparation of chiral aptazepine derivatives on coated and immobilized polysaccharide‐based chiral stationary phases

Direct HPLC enantioseparation of chiral aptazepine derivatives on coated and immobilized polysaccharide‐based chiral stationary phases

Chiral recognition ability and solvent versatility of bonded amylose tris(3,5‐dimethylphenylcarbamate) chiral stationary phase: Enantioselective liquid chromatographic resolution of racemic N‐alkylated barbiturates and thalidomide analogs

High‐Throughput Screening and Method Development Strategies to Separate Chiral Drug Compounds in HPLC, SFC, and CE

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