Bezhan Chankvetadze

Bezhan Chankvetadze
Ivane Javakhishvili Tbilisi State University | TSU · Institute of Physical and Analytical Chemistry

PhD

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310
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Publications (310)
Article
It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread o...
Article
In this paper enantiomers of selected chiral agrochemicals representing various structural classes were separated by using nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) employing a capillary column packed with silica particles containing immobilized amylose tris(3-chloro-5-methylphenylcarbamate) (i-ADMPC) as a chira...
Article
Planar chiral halogenated ferrocenes have come in useful as synthetic intermediates over the years, allowing for the preparation of functionalized derivatives for catalysis, material science, optoelectronics, and medicinal chemistry. Despite their chemical interest, few halogenated planar chiral ferrocenes have been prepared in enantiopure form by...
Article
Sulfur as a stereogenic center can be found in synthetic compounds and natural products. The current study evaluated the enantioseparation of 16 chiral (benzylsulfinyl)benzamides compounds by capillary electrophoresis using charged cyclodextrins (CDs) as chiral selectors in 50 mM sodium acetate buffer, pH 5.5. The sulfoxides varied in the type and...
Article
Planar chiral ferrocenes are well-known compounds that have attracted interest for application in synthesis, catalysis, material science, and medicinal chemistry for several decades. In spite of the fact that asymmetric synthesis procedures for obtaining enantiomerically enriched ferrocenes are available, sometimes, the accessible enantiomeric exce...
Article
This article summarizes our cooperation with the research group of Prof. Yoshio Okamoto at Nagoya University during the period of time between 1992 and 2005. Although the text deals entirely with enantioseparations in high-performance liquid chromatography, capillary electrophoresis, and capillary electrochromatography, this is not a detailed revie...
Article
Full-text available
In the last few years, chiral 4,4’-bipyridine derivatives have been developed for different applications in catalysis, enantioseparation science, supramolecular and theoretical chemistry by modulating the activity of the molecular system through the introduction of specific substituents in the heteroaromatic scaffold. More recently, the biological...
Article
In the last few years, chiral 4,4’-bipyridine derivatives have been developed for different applications in catalysis, enantioseparation science, supramolecular and theoretical chemistry by modulating the activity of the molecular system through the introduction of specific substituents in the heteroaromatic scaffold. More recently, the biological...
Article
Full-text available
A high-molecular water-soluble preparation from stems of Borago officinalis (Boraginaceae family) was isolated. According to data from UV, IR, 1 H, 13 C NMR, gCOSY and 2D heteronuclear 1 H/ 13 C gHSQCED experiments, the main chemical constituent of this water-soluble high-molecular preparation from stems of Borago officinalis (HMP-BS) was found to...
Article
Fractionation of biologically active poly[3-(3,4-dihydroxyphenyl)glyceric acid] (PDPGA)-preparation from Symphytum asperum, distribution of PDPGA and polysaccharides impurity using high performance size exclusion chromatography (HPSEC) coupled with multi angle laser light scattering (MALLS), refractive index detector (RID) and membrane ultrafiltrat...
Article
Full-text available
Fractionation and molecular weight distribution of biologically active poly[3-(3,4-dihydroxyphenyl) glyceric acid] (PDPGA)-preparation from Symphytum asperum were carried out. Molecular weights and contents of different fractions for PDPGA-preparation were simultaneously determined using high performance size exclusion chromatography (HPSEC) couple...
Article
We report source specific isotope ratios of levoglucosan, the specific biomass burning tracer, in aerosol particle from the combustion of selected woods used for domestic heating in Europe, of coals containing cellulose (lignites) as well as of corn, a C4 plant. Here, we combine compound specific δ¹³C measurements of levoglucosan with total carbon...
Article
The separation of daclatasvir and its R,R,R,R-enantiomer was studied by capillary electrophoresis using various randomly methylated β-CDs and the single isomer heptakis(2,6-di-O-methyl)-β-CD (2,6-DM-β-CD) as chiral selectors in an acidic background electrolyte. Opposite enantiomer migration order was observed for randomly substituted CDs compared t...
Article
In capillary electrophoresis an enantioseparation of daclatasvir (DCV) was observed in case of heptakis(2,6-di-O-methyl)-β-CD, heptakis(2-O-methyl)-β-CD and β-CD, while two peaks with a plateau were noted for heptakis(2,3,6-tri-O-methyl)-β-CD and heptakis(2,3-di-O-methyl)-β-CD indicating a slow equilibrium. Heptakis(6-O-methyl)-β-CD and heptakis(3-...
Article
Cyclodextrins (CD) are cyclic oligosaccharides consisting of α-D-glucopyranosyl units linked through 1,4-linkages, which are obtained from enzymatic degradation of starch. The co-existence of hydrophilic and hydrophobic regions in the same structure makes these macrocycles extremely versatile as complexing host with application in food, cosmetics,...
Article
2’-(4-Pyridyl)- and 2’-(4-hydroxyphenyl)-TCIBPs (TCIBP = 3,3’,5,5’-tetrachloro-2-iodo-4,4’-bipyridyl) are chiral compounds that showed interesting inhibition activity against transthyretin fibrillation in vitro. We became interested in their enantioseparation since we noticed that the M-stereoisomer is more effective than the P-enantiomer. Based th...
Article
The recognition power and affinity pattern of various cyclodextrins (CD) towards the enantiomers of tetrahydrozoline (THZ) were studied using capillary electrophoresis (CE). As expected, affinity of THZ enantiomers and selectivity of recognition towards CD derivatives was strongly dependent on the cavity size and substituent type and pattern on the...
Article
Full-text available
Based on previously reported chiral separation of free amino-acids (AAs) using packed-column supercritical fluid chromatography (pSFC), it was desirable to investigate parameters influencing the response of evaporative light scattering detector (ELSD). The effect of several parameters, such as SFC conditions (outlet pressure, temperature and flow r...
Article
Full-text available
The chalcogen bond (ChB) is a noncovalent interaction based on electrophilic features of regions of electron charge density depletion (σ-holes) located on bound atoms of group VI. The σ-holes of sulfur and heavy chalcogen atoms (Se, Te) (donors) can interact through their positive electrostatic potential (V) with nucleophilic partners such as lone...
Article
Capillary electrochromatography (CEC) represents a technique with less than 30 years of intense development and in this period this technique has seen huge promise, fast development, stagnation, and significant decline of innovative activity. The major goal of the present overview is not to present an extensive review of the literature on chiral CE...
Article
Full-text available
In a recent study, opposite enantiomer elution order was observed for ketoprofen enantiomers on two amylose-phenylcarbamate-based chiral columns with the same chemical composition of the chiral selector but in one case with coated while in the other with an immobilized chiral selector. In the present study, the influence of this uncommon effect on...
Article
Full-text available
In the present work, the development and application of two HPLC methods enabling the semipreparative enantioresolution of 1-(biphenyl-3-yl)-2-(1H-imidazol-1-yl)ethanol (1) and 1-[4-[(4-bromobenzyl)oxy]phenyl]-2-(1H-imidazol-1-yl)ethanol (2), two among the most potent and selective heme oxygenase-1 (HO-1) inhibitors known, are described. During the...
Article
An unusual convex-upward van Deemter curve was observed for the more retained enantiomer of a chiral sulfoxide (2-(benzylsulfinyl)benzamide) on a cellulose tris(4-chloro-3-methylphenylcarbamate)-based chiral stationary phase (CSP), prepared on silica particles of 1000 Å pore size. In contrast, the firstly eluted enantiomer of the same molecule exhi...
Article
During a screening of cyclodextrins (CDs) as chiral selectors for the separation of daclatasvir (DCV) and its enantiomer by capillary electrophoresis (CE), an unusual phenomenon for CDs was observed, that is two peaks with a plateau in between using γ-CD as chiral selector. The same result was encountered when enantiopure DCV was injected or when a...
Article
In this study superficially porous silica particles with a nominal pore size of 450 Å and average particle size of 2.6 micrometers was compared to fully porous silica particles with nominal particle size 3 micrometers and nominal pore size 1000 A as carriers for a polysaccharide based chiral selector for the separation of enantiomers in high-perfor...
Article
In the present study separation of enantiomers of some chiral neutral, basic and weakly acidic analytes was investigated on the chiral stationary phase (CSP) made by covalent immobilization of amylose tris(3-chloro-5-methylphenylcarbamate) onto aminopropylsilanized (APS) silica in nano-liquid chromatography (nano-LC) in aqueous methanol or acetonit...
Article
In this study, amylose- and cellulose-phenylcarbamate-based chiral columns with different chiral-selector (CS) chemistries were compared to each other for the separation of enantiomers of basic chiral analytes in acetonitrile and aqueous-acetonitrile mobile phases in HPLC. For two chemistries the amylose-based columns with coated and immobilized CS...
Article
Full-text available
According to UV, IR, 1H NMR data and to a 2D heteronuclear 1H/13C HSQC experiment the main chemical constituent of water-soluble high-molecular preparation of Cynoglossum officinale (Boraginaceae) (HMP-CO) by analogy with S. asperum, S. caucasicum, S. officinale, S. grandiflorum and Anchusa italica high-molecular fractions (HMFs), was found to be a...
Article
The major goal of this study was to determine the affinity pattern of the terbutaline (TB) enantiomers towards a-, b-, g- and heptakis(2,3-di-O-acetyl)-b-cyclodextrins and using nuclear magnetic resonance (NMR) spectroscopy for the understanding of the fine mechanisms of interaction between the cyclodextrins (CD) and TB enantiomers. It was shown on...
Article
Three novel oxirane monomers, 2‐methoxycarbonyl‐3‐(3,4‐dibenzyloxyphenyl)oxirane (MDBPO), 2‐benzyloxycarbonyl‐3‐(3,4‐dibenzyloxyphenyl)oxirane (BDBPO), and 2‐t‐butyloxycarbonyl‐3‐(3,4‐dibenzyloxyphenyl)oxirane (TBDBPO) are prepared and polymerized using BF3‐OEt2 in CH2Cl2 to yield polyethers. The monomers smoothly lead to polymers under the cationi...
Article
The separation of 14 chiral sulfoxides was systematically studied on 12 cellulose-based chiral columns in acetonitrile and acetonitrile-water mobile phases. Out of all monosubstituted methylphenylcarbamates of cellulose the one having a methyl moiety in position 3 showed more universal chiral resolving ability compared to 2- and 4-substituted deriv...
Article
In the present study separation of enantiomers of some chiral neutral and weakly acidic analytes was investigated on the chiral stationary phase (CSP) made by covalent immobilization of amylose tris(3-chloro-5-methylphenylcarbamate) onto silica in nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) in acetonitrile and aqu...
Chapter
This chapter summarizes the application of polysaccharide-based chiral stationary phases (CSPs) for separation of enantiomers in high-performance liquid chromatography (HPLC). Since this book contains dedicated chapters on enantioseparations using supercritical fluid chromatography (SFC), or capillary electrochromatography (CEC), the application of...
Article
In this overview the goal of the authors was to analyze from the historical perspective the reasons of success and failure of chiral capillary electrophoresis. In addition, the current trends are analyzed, unique advantages of capillary electrophoresis are highlighted and some future directions are discussed. This article is protected by copyright....
Article
The separation of enantiomers of some chiral weak acids was studied in HPLC with chiral HPLC columns prepared by coating or covalent immobilization of the same chiral selector, namely amylose tris(3-chloro-5-methylphenylcarbamate) onto silica. After screening some representatives of arylpropionic acid derivatives, coumarins and barbiturates in hydr...
Article
This article describes our attempt to re-visit the role of temperature in the separation of enantiomers with polysaccharide-based chiral columns in high-performance liquid chromatography (HPLC). Rarely observed increased retention and separation factors with increasing temperature, as well as temperature dependent reversal of enantiomer elution ord...
Article
The major goal of this study was to determine the affinity pattern of brombuterol (BB) enantiomers towards various cyclodextrins (CD) and to evaluate the potential of NMR spectroscopy for understanding fine mechanisms of interactions between CDs and BB enantiomers. Separation of BB enantiomers was performed in a fused‐silica capillary using a phosp...
Article
In this short communication preliminary results are reported on the separation of enantiomers of underivatized amino acids on polysaccharide-based chiral columns in sub/super-critical fluid chromatography (SFC). Racemic mixtures of 14 amino acids were used to evaluate the chiral recognition ability of 8 different polysaccharide-based chiral columns...
Article
The affinity pattern of terbutaline enantiomers towards various cyclodextrins was studied using capillary electrophoresis. The affinity pattern of terbutaline enantiomers was the same towards all studied cyclodextrins except heptakis(2-O-methyl-3,6-di-O-sulfo)-β-CD. Nuclear magnetic resonance spectroscopy was used for understanding of fine structur...
Article
Our earlier studies have demonstrated the applicability of polysaccharide-based chiral selectors in combination with superficially porous (or core-shell) silica (SPS) particles for the preparation of highly efficient chiral stationary phases (CSP). In earlier studies, CSPs were prepared by coating (adsorption) of the chiral selector onto the surfac...
Article
In this study our preliminary attempt for obtaining fast and highly efficient separations of enantiomers in high-performance liquid chromatography with slightly modified state-of-the-art commercial instrumentation is described. In order to reach this goal after careful selection of chiral analytes, the preparation of chiral stationary phase (CSP),...
Article
The first separation of enantiomers in capillary electrophoresis (CE) counts slightly longer than three decades. Fast development of the practice and theory of chiral CE occurred in the past 30 years and today one can consider this technology to have a solid and mature theoretical background. The goal of the present review is not only to summarize...
Article
A targeted CE-MS approach was developed for the chiral analysis of biologically relevant amino acids in artificial cerebrospinal fluid (aCSF). In order to achieve chiral resolution, the five amino acids (Ser, Asn, Asp, Gln and Glu) were derivatized with (+)-1-(9-fluorenyl)ethyl chloroformate ((+)-FLEC). The diastereoselectivity was found to be high...
Article
The migration order of the enantiomers of medetomidine in the presence of cyclodextrins studied by capillary electrophoresis in phosphate buffer, pH 2.5, depended on the cavity size and the substitution pattern of the cyclodextrins. Opposite migration order was observed in the presence of β-cyclodextrin (β-CD) and γ-cyclodextrin (γ-CD) as well as r...
Article
A high-performance liquid chromatography method for the determination of dextromepromazine, levomepromazine sulfoxide and 2-methoxyphenothiazine in levomepromazine samples was developed. The separation of the analytes was achieved within 10 min on a stationary phase containing cellulose tris(4-methylbenzoate) as chiral selector. The mobile phase co...
Article
The interplay between structural details of chiral analytes and selectors in the separation of 14 chiral sulfoxides was systematically studied on 18 different polysaccharide-based chiral columns. Retention and enantioselectivity of a set of chiral sulfoxides were of primary interest. Several of chiral columns studied exhibited quite powerful chiral...
Article
Full-text available
The separation of enantiomers of over 175 randomly selected chiral acidic, basic, and neutral compounds was studied on 4 polysaccharide-based chiral columns made by coating or covalent attachment of cellulose 3,5-dichlorophenylcarbamate or amylose 3,5-dimethylphenylcarbamate on the surface of silica. Triscarbamate derivatives of cellulose or amylos...
Article
Full-text available
C hiral antifungals are used as veterinary and human drugs, as well as agrochemicals. They are especially used to cure fungal infections that commonly occur on the nails, hair and skin. Those antifungals in use which show efficacy against fungal diseases are mostly target specific components of fungal plasma membrane or its biosynthetic pathways. E...
Article
Full-text available
Phenolic compounds of red wines, catechins, flavonols, phenolcarbonic acids, anthocyanins, resveratrol are characterized by high antioxidanat activity and sharply reduce the risk of numerous diseases. Nowadays an increasing demand on red wines in the world market is conditioned by their antioxidant effect. However, according to antioxidanat activit...
Article
The present study reports successful separations of enantiomers of selected chiral sulfoxides with very high separation factor in high-performance liquid chromatography by using chiral columns prepared with the chiral selector cellulose tris(4-chloro-3-methylphenylcarbamate). High separation factors were observed in polar organic, as well as in hyd...
Article
While the amino acids, enzymes and hormones are chiral, chirality plays significant role in the life of plants, animals, as well as the human being. Chirality of molecules is important in various industries, such as pharmaceutical, agricultural, food, electronic, etc. Chiral drugs may have different absorption, distribution, biotransformation and e...
Chapter
This chapter summarizes the major developments in the field of liquid chromatographic separation of enantiomers. After short historical overview, the materials and technologies used for analytical and preparative scale separation of enantiomers in high-performance liquid chromatography, nanoliquid chromatography, simulated moving-bed chromatography...
Conference Paper
Full-text available
Chiral imidazole and triazole derivatives are widely used human and veterinary drugs [1] and also agrochemicals (fungicides) [2,3]. Enantioselectivity of chiral imidazole and triazole derivatives in biological action [2-4], in metabolism and pharmacokinetics, as well as in activity, accumulation and degradation in plants, vegetables, soils and in e...
Article
NMR spectroscopy experiments, molecular dynamics simulations, and theoretical chemistry calculations provide insight into the structural and energetic determinants of the distinct binding of clenpenterol enantiomers to two cyclodextrins and the migration order reversal of their respective inclusion complexes in capillary electrophoresis.
Article
A new experimental chiral stationary phase containing amylose 3,5-dimethylphenylcarbamate immobilized onto silica gel (i-ADMPC) was packed in 100μm I.D. fused silica capillary and used for the chiral separation of eight selected flavanone derivatives in polar organic mobile phase by using different miniaturized techniques, such as nano-liquid chrom...
Conference Paper
A selective and sensitive stability indicting HPLC method was developed for the analysis of miconazole.For thispurpose, six polysaccharide-based chiralcolumns(Lux Cellulose-1, Lux Cellulose-2, Lux Cellulose-3, Lux Cellulose-4, Lux Amylose-1, Lux Amylose-2) with the dimensions of 250 x 4.6 mm for separation of enantiomers of miconazole was evaluated...
Article
Asymmetric sulfoxides is a particular case of chirality that may be found in natural as well as synthetic products. Twenty-four original molecules containing a sulfur atom as a centre of chirality were analyzed in supercritical fluid chromatography on seven polysaccharide-based chiral stationary phases (CSP) with carbon dioxide – methanol mobile ph...
Article
In the present study an attempt was made to achieve separation of enantiomers within a minute in nano-liquid chromatography (nano–LC) and capillary electrochromatography (CEC). In order to achieve this goal several parameters were optimized from the viewpoint of the property of chiral analytes, concentration of the chiral selector in the packing ma...
Article
In the present study the enantiomer migration order (EMO) of enilconazole in the presence of various cyclodextrins (CDs) was investigated by capillary electrophoresis (CE). Opposite EMO of enilconazole were observed when β-CD or the sulfated heptakis(2-O-methyl-3,6-di-O-sulfo)-β-CD (HMDS-β-CD) was used as the chiral selectors. Nuclear Magnetic Reso...
Article
Full-text available
According to data of IR, 1H NMR, gCOSY and 2D 1H/13C gHSQCED experiments caffeic acid-derived polymer, namely poly[3-(3,4-dihydroxyphenyl)glyceric acid] (PDPGA) was detected in watersoluble high-molecular preparation of Symphytum grandiflorum DC (HMP-SG) by analogy with S. asperum, S. caucasicum, S.officinale and Anchusa italica high-molecular weig...
Article
According to data of IR, 1H NMR, gCOSY and 2D 1H/13C gHSQCED experiments caffeic acid-derived polymer, namely poly[3-(3,4-dihydroxyphenyl)glyceric acid] (PDPGA) was detected in watersoluble high-molecular preparation of Symphytum grandiflorum DC (HMP-SG) by analogy with S. asperum, S. caucasicum, S.officinale and Anchusa italica high-molecular weig...
Article
Our earlier studies on the preparation of chiral stationary phases (CSP) based on superficially porous (or core-shell) silica (SPS) particles for the separation of enantiomers in HPLC have provided proof to the advantages of such sorbents. In particular, higher enantioselectivity was observed with the columns packed with superficially porous CSP co...
Article
When polysaccharide-based chiral columns are used in combination with aqueous-organic mobile phases for the separation of enantiomers in high-performance liquid chromatography the separation mode is commonly called "reversed-phase" in analogy to achiral separations. In several earlier and recent studies on neutral and basic chiral analytes it was s...
Article
This review deals with the applications of nuclear magnetic resonance (NMR) spectroscopy to understand the mechanisms of chiral separation in capillary electrophoresis (CE). It is accepted that changes observed in the separation process, including the reversal of enantiomer migration order (EMO), can be caused by subtle modifications in the molecul...
Article
The first ever report on the preparation of chiral stationary phases (CSP) based on superficially porous silica (SPS) particles for the separation of enantiomers in HPLC demonstrated clear advantages of such materials. Higher enantioselectivity at the comparable content of a chiral selector, limited dependence of plate height on the mobile phase fl...
Article
Full-text available
The separation of enantiomers of flavanone and 5 chiral flavanone derivatives was studied on two experimental polysaccharide-based chiral columns by high-performance liquid chromatography with methanol, ethanol, acetonitrile, n-hexane/ethanol and n-hexane/2-propanol as mobile phases with emphasis on the effect of analyte and chiral selector structu...