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Yıldırım A, Avcı C. A simple and efficient approach for the synthesis of cholesterol esters of long-chain saturated fatty acids by using Ph 3P·SO 3 as a versatile organocatalyst. Steroids 2022; 183:109011. [PMID: 35381272 DOI: 10.1016/j.steroids.2022.109011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/02/2022] [Accepted: 03/09/2022] [Indexed: 11/22/2022]
Abstract
Cholesteryl esters are more nonpolar compounds formed by the conjugation of cholesterol with fatty acids containing a long hydrocarbon chain. These ester molecules do not participate in the composition of the cell membranes and are found in lipid droplets. Because this form of cholesterol can be packaged in a larger amount in lipoproteins, the transport of cholesterol is more effective, and also, these esters play an important role in cholesterol metabolism. Moreover, some of their hydroperoxide derivatives are biologically active components of minimally modified low-density lipoprotein (mmLDL). In recent years, these esters have attracted attention in many industrial and medical applications. In this study, a triphenylphosphine-sulfur trioxide adduct efficiently catalyzed the esterification reactions between homologous long-chain saturated monocarboxylic or dicarboxylic fatty acids and cholesterol molecule in toluene. In these reactions, the triphenylphosphine-based adduct acts as a source of sulfur trioxide. Reactions were performed at 110 °C with equimolar amounts of the reagents except in the case of dicarboxylic acids, and two equimolar of cholesterol was used to afford the corresponding homologous cholesteryl esters in good to excellent yields. The present developed method has advantages such as being simpler, practical, and less toxic than the existing ones as well as enabling the synthesis of the related esters with higher yields.
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Affiliation(s)
- Ayhan Yıldırım
- Faculty of Arts and Sciences, Department of Chemistry, Bursa Uludağ University, 16059 Bursa, Turkey.
| | - Cansu Avcı
- Faculty of Arts and Sciences, Department of Chemistry, Bursa Uludağ University, 16059 Bursa, Turkey
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2
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Grzywiński D, Szumski M, Buszewski B. Cholesterol-based polymeric monolithic columns for capillary liquid chromatography. Part II. J Chromatogr A 2015; 1408:145-50. [PMID: 26187765 DOI: 10.1016/j.chroma.2015.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/16/2015] [Accepted: 07/05/2015] [Indexed: 11/19/2022]
Abstract
This paper presents a second part of our research devoted to cholesterol-based polymeric monolithic stationary phase. The obtained capillary columns were successfully used for separations of alkylbenzenes, steroid hormones and polycyclic aromatic hydrocarbons during isocratic or gradient elutions. The columns showed excellent thermal stability. Increasing the temperature resulted in decrease of the retention factors and peak widths, but selectivity and efficient separations have been retained in the studied temperature range of 20 to100°C. Additionally, the van't Hoff model presented a non-linear relationship of lnk versus 1/T plots, which is likely the result of liquid crystal properties of cholesterol. The studied capillary monolithic columns showed extremely fast re-equilibration after gradient elution and found to be stable under such conditions as: fast flow rate, high acetonitrile content in the mobile phase (no swelling) and high temperature.
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Affiliation(s)
- Damian Grzywiński
- Nicolaus Copernicus University in Toruń, Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, 7 Gagarin St., 87-100 Torun, Poland; Nicolaus Copernicus University in Toruń, Center for Modern Interdisciplinary Technologies, 4 Wilenska St., 87-100 Torun, Poland
| | - Michał Szumski
- Nicolaus Copernicus University in Toruń, Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, 7 Gagarin St., 87-100 Torun, Poland; Nicolaus Copernicus University in Toruń, Center for Modern Interdisciplinary Technologies, 4 Wilenska St., 87-100 Torun, Poland.
| | - Bogusław Buszewski
- Nicolaus Copernicus University in Toruń, Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, 7 Gagarin St., 87-100 Torun, Poland; Nicolaus Copernicus University in Toruń, Center for Modern Interdisciplinary Technologies, 4 Wilenska St., 87-100 Torun, Poland
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3
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Szumski M, Grzywiński D, Buszewski B. Cholesterol-based polymeric monolithic columns for capillary liquid chromatography. J Chromatogr A 2014; 1373:114-23. [PMID: 25465372 DOI: 10.1016/j.chroma.2014.11.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 11/05/2014] [Accepted: 11/08/2014] [Indexed: 11/26/2022]
Abstract
A novel, cholesterol-based polymeric monolithic stationary phase for capillary liquid chromatography, was prepared by thermally initiated in-situ polymerization. Cholesteryl methacrylate (CholMA) was used as a functional monomer and trimethylolpropane trimethacrylate (TRIM) was a cross-linker, while azobisisobutyronitrile (AIBN) was an initiator. Isooctane and toluene were chosen as "poor" and "good" solvent, respectively, as constituents of the porogen solvent. Isocratic elutions of alkylbenzenes and separation of the testing mixture of o-terphenyl and triphenylene were conducted for all of the monoliths to assess their hydrophobicity and planar selectivity characteristic for cholesterol-based stationary phases. The synthesized columns demonstrated efficiency exceeding N=10,000 plates and a plate height of ca. H=30 μm. Column preparation was found to be highly reproducible; the relative standard deviation (RSD) values (n=3) for day-to-day and column-to-column were less than 4.08 and 2.02%, respectively, based on retention factor of alkylbenzenes.
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Affiliation(s)
- Michał Szumski
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina St., 87-100 Torun, Poland.
| | - Damian Grzywiński
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina St., 87-100 Torun, Poland
| | - Bogusław Buszewski
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina St., 87-100 Torun, Poland
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Abstract
"Chance favors the prepared mind." Louis Pasteur. "Reality is merely an illusion, albeit a very persistent one". Albert Einstein. As so succinctly stated by these two famous scientists, it is sometimes necessary to step outside the bounds of traditional thinking and look at ideas that many claim to be impossible based on preconceived notions rather than experimental data. This review is dedicated to those open-minded scientists who are willing to evaluate new concepts objectively rather than dismiss new approaches with outdated theories.
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Affiliation(s)
- Joseph J Pesek
- Department of Chemistry, San Jose State University, San Jose, CA, USA.
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Bocian S, Vajda P, Felinger A, Buszewski B. Solvent excess adsorption on the stationary phases for reversed-phase liquid chromatography with polar functional groups. J Chromatogr A 2008; 1204:35-41. [PMID: 18703199 DOI: 10.1016/j.chroma.2008.07.056] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 07/11/2008] [Accepted: 07/11/2008] [Indexed: 11/18/2022]
Abstract
The measurement of acetonitrile and methanol adsorption was carried out on stationary phases with specific functionalities. The results were compared with the adsorption of those solvents on alkyl-modified adsorbents. This comparison allows us to describe the effect of polar groups on the adsorption of the organic modifiers. Our results clearly demonstrate how the functional groups modify the chromatographic properties of the homogeneous hydrophobic adsorbents.
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Affiliation(s)
- Szymon Bocian
- Department of Environmental Chemistry & Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7, Torun, Poland
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Catabay AP, Pesek JJ, Matyska MT, Jinno K. PHARMACEUTICAL APPLICATIONS USING CHOLESTERYL-10-UNDECENOATE BONDED PHASE IN MICROCOLUMN LIQUID CHROMATOGRAPHY. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-100101710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- A. P. Catabay
- a School of Materials Science, Toyohashi University of Technology , Tempaku-cho, Toyohashi , 441-8580 , Japan
| | - J. J. Pesek
- b Department of Chemistry , San Jose State University , San Jose , CA , 95192 , U.S.A
| | - M. T. Matyska
- b Department of Chemistry , San Jose State University , San Jose , CA , 95192 , U.S.A
| | - K. Jinno
- c School of Materials Science, Toyohashi University of Technology , Tempaku-cho, Toyohashi , 441-8580 , Japan
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Saito Y, Ohta H, Jinno K. Design and characterization of novel stationary phases based on retention behavior studies with various aromatic compounds. J Sep Sci 2003. [DOI: 10.1002/jssc.200390029] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Pesek JJ, Matyska MT, Dawson GB, Wilsdorf A, Marc P, Padki M. Cholesterol bonded phase as a separation medium in liquid chromatography. Evaluation of properties and applications. J Chromatogr A 2003; 986:253-62. [PMID: 12597632 DOI: 10.1016/s0021-9673(02)01958-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An extensive survey of the properties and separation capabilities of a cholesterol bonded phase is reported. The intermediate hydrophobic/hydrophilic properties of the bonded cholesterol material allows this stationary phase to be used for both reversed-phase and aqueous normal-phase separations. Interesting high selectivity is reported for the structural isomers of some antibiotics. The cholesterol bonded material does not display "phase collapse" in high aqueous content mobile phases. Variable temperature studies demonstrate that substantial structural changes of the bonded moiety occur that might be used to control selectivity. Finally, separation of some enantiomers of compounds with a variety of chemical structures is reported under reversed-phase conditions indicating that the cholesterol material may be chiral stationary phase with a broad range of applicability.
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Affiliation(s)
- Joseph J Pesek
- Department of Chemistry, College of Science, San Jose State University, One Washington Square, San Jose, CA 95192, USA.
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Shi W, Palmer CP. Effect of pendent group structures on the chemical selectivity and performance of sulfonated copolymers as novel pseudophases in electrokinetic chromatography. Electrophoresis 2002; 23:1285-95. [PMID: 12007128 DOI: 10.1002/1522-2683(200205)23:9<1285::aid-elps1285>3.0.co;2-a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Amphiphilic copolymers of 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) with dihydrocholesteryl acrylate (pDHCHAt) or tert-octyl acrylamide (ptOAm) as comonomers were synthesized, characterized and used as new polymeric pseudostationary phases in electrokinetic chromatography. High-efficiency separations with theoretical plates around 500,000 to 870,000/m were achieved. Linear solvation energy relationships analysis of 20 solutes was performed to investigate the retention mechanism. Polycyclic aromatic hydrocarbons (PAHs) were separated under 30% v/v acetonitrile. The separation of nine aromatic model solutes by pDHCHAt showed significantly different selectivity from that of sodium dodecyl sulfate. Although only minor difference in selectivity was found for small aromatic compounds on pDHCHAt and poly(AMPS-lauryl acrylate), significantly different retention mechanism was found for PAHs and n-dodecanophenone comparing both copolymers. Significant chemical selectivity difference was found for selected small aromatic compounds on ptOAm and poly(AMPS-stearyl acrylamide).
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Affiliation(s)
- Wei Shi
- Department of Chemistry, New Mexico Institute of Mining & Technology, Socorro, NM, USA
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Matyska MT, Pesek JJ, Boysen RI, Hearn MT. Electrochromatographic characterization of etched chemically-modified capillaries with small synthetic peptides. J Chromatogr A 2001; 924:211-21. [PMID: 11521867 DOI: 10.1016/s0021-9673(01)00830-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this investigation, various capillary electrochromatographic (CEC) experiments have been employed to characterize the properties of etched, chemically-modified surfaces of open tubular capillary columns with peptides as solute probes and under conditions of variable voltage, temperature and solvent composition. The separation performance of etched capillaries with either n-octadecyl or liquid crystal moieties derived from a cholesterol phase bonded to the surface were compared. With the liquid crystal bonded species, interesting and significantly different variations in retention behavior of peptides are obtained compared to those observed with the corresponding n-octadecyl modified surfaces by changes in temperature, solvent composition and field strength. These peptide separations illustrate the usefulness of this CEC approach for practical applications, where both the retention characteristics of the charged analytes as well as the selectivity differences due to the surface properties of the etched chemically-modified surfaces of open tubular capillary columns can be rationally modulated. As in HPLC, appropriate choice of CEC experimental variables, including the chemical properties of the immobilized ligand(s), represents a powerful tool for optimizing resolution.
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Affiliation(s)
- M T Matyska
- Department of Chemistry, San Jose State University, CA 95192-0101, USA
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Open Tu ular Approaches to Capillary Electrochromatography. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0301-4770(01)80079-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Pesek JJ, Matyska MT, Muley S. Synthesis and characterization of a new type of chemically bonded liquid crystal stationary phase for HPLC. Chromatographia 2000. [DOI: 10.1007/bf02535716] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Jinno K, Sawada H, Catabay AP, Watanabe H, Sabli NB, Pesek JJ, Matyska MT. Comparison of separation behavior of benzodiazepines in packed capillary electrochromatography and open-tubular capillary electrochromatography. J Chromatogr A 2000; 887:479-87. [PMID: 10961335 DOI: 10.1016/s0021-9673(99)01198-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Packed column capillary electrochromatography (CEC), open-tubular CEC and microcolum liquid chromatography (LC) using a cholesteryl silica bonded phase have been studied to compare the retention behavior for benzodiazepines. It has been found that packed column CEC gives better resolution, faster analysis time than microcolumn LC for benzodiazepines maintaining similar selectivity except for some solutes which are charged species under the separation conditions. However, open-tubular CEC gave different selectivities to a larger extent for charged benzodiazepines from that which should be produced by the chromatographic properties of the cholesteryl silica phase. Charged species migration times are mainly influenced by electrophoretic mobility rather than the chromatographic interactions.
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Affiliation(s)
- K Jinno
- School of Materials Science, Toyohashi University of Technology, Japan.
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Matyska MT, Pesek JJ, Katrekar A. Open Tubular Capillary Electrochromatography Using Etched Fused-Silica Tubing Modified with Chemically Bonded Liquid Crystals. Anal Chem 1999. [DOI: 10.1021/ac9907989] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maria T. Matyska
- Department of Chemistry, San Jose State University, San Jose, California 95192
| | - Joseph J. Pesek
- Department of Chemistry, San Jose State University, San Jose, California 95192
| | - Anjali Katrekar
- Department of Chemistry, San Jose State University, San Jose, California 95192
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Retention behaviour of products extracted from oriental medicine formulations in high-performance liquid chromatography on octadecyl acrylate-modified silicas. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(99)00297-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Pesek JJ, Matyska MT, Oliva M, Evanchic M. Synthesis and characterization of bonded phases made via hydrosilation of alkynes on silica hydride surfaces. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(98)00549-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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