Determination of pKa values of benzimidazole derivatives from mobility obtained by capillary electrophoresis.

Dissociation constants of benzimidazole derivatives have been determined using capillary zone electrophoresis (CZE). Since CZE is a separation method, high purity and known concentration for the samples is not necessary because only mobilities are measured. The precision of pK(a) measurements of seven compounds is useful to observe pK(a) shifts induced by chemical variations.

Enantioseparation of chiral benzimidazole derivatives by electrokinetic chromatography using sulfated cyclodextrins.

Baseline separation of 18 new substituted benzimidazole derivatives, potent AMP-activated protein kinase (AMPK) activators, with one chiral center, was achieved by CD-EKC using sulfated and highly sulfated CDs (SCDs and HS-CDs) as chiral selectors. The influence of the type and concentration of the chiral selectors on the enantioseparations was investigated. The SCDs exhibit a very high enantioselectivity power since they allow excellent enantiomeric resolutions compared to those obtained with the neutral CDs.

Preparative enantiomeric separation of potent AMP-activated protein kinase activator by HPLC on amylose-based chiral stationary phase. Determination of enantiomeric purity and assignment of absolute configuration.

The development of high performance liquid chromatography method on amylose-based stationary phases (Chiralpak AD) has permitted to achieve the preparative enantioseparation of one benzimidazole derivative, potent-AMP-kinase (AMPK) activator with satisfactory yields. Analytical enantioseparation method was optimized and validated to determine the enantiomeric purity. Using the UV detection, repeatability, limits of detection (LD) and quantification (LQ) were determined.

Enantiomeric analysis of baclofen analogs by capillary zone electrophoresis, using highly sulfated cyclodextrins: Inclusion ionization constant pKa determination.

Using cyclodextrin-capillary zone electrophoresis (CD-CZE), baseline separation of baclofen phaclofen, saclofen, and hydroxy-saclofen, potent gamma-aminobutyric acid(B) (GABA(B)) agonist or antagonists was achieved. A method for the enantioresolution of those analogs of GABA was developed using anionic cyclodextrins (highly sulfated CD or highly S-CD) as chiral selectors and capillaries dynamically coated with polyethylene oxide (PEO). With charged CDs we observed good resolutions due to the large electrophoretic mobility of these chiral selectors opposite to the mobility of the solutes.

Enantiomerical excess determination, purification and biological evaluation of (3S) and (3R) alpha,beta-butenolide analogues of isobenzofuranone.

The asymmetric synthesis of isobenzofurane analogues, new potential antiviral agents, is reported. High performance liquid chromatography (HPLC) was the technique chosen to separate the enantiomers. We describe this chiral separation and then determine the enantiomerical excess.