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  • 1
    Electronic Resource
    Electronic Resource
    Computation of low-energy crystalline arrangements of cellulose triacetate (1992)
    s.l. : American Chemical Society
    Macromolecules 25 (1992), S. 709-720 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00028a033
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  • 2
    Electronic Resource
    Electronic Resource
    Achiral derivatization as a means of improving the chromatographic resolution of racemic alcohols on benzoylcellulose CSPs (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 10 (1998), S. 492-498 
    Details
    ISSN: 0899-0042
    Keywords: racemate ; enantiomer ; HPLC ; chiral stationary phase ; benzoylcellulose ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The advantages that can be gained from derivatization of various racemic aliphatic and aromatic alcohols prior to enantiomeric chromatographic separation have been systematically investigated for a series of benzoate derivatives. Three cellulose-based CSPs available in the pure polymeric form - tribenzoyl cellulose (TBC), meta-methylbenzoyl cellulose (MMBC), and para-methylbenzoyl cellulose (PMBC) - were selected and several benzoate derivatives varying in the nature and the position of the substituent on the benzoyl group were prepared and analysed. TBC clearly gives the broadest application range, and among the different benzoate esters the best selectivity was generally obtained with either the 4-methoxybenzoate or the 4-methylbenzoate derivatives. Based on these results, some empirical rules could be formulated for optimizing the enantiomeric separation of racemic alcohols, which make up one of the most important classes of chemical substances used as drugs and biocides, or as building blocks for their synthesis. An application of this approach to the preparative separation of the enantiomers of a drug intermediate is also shown. Chirality 10:492-498, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Benzoylcellulose derivatives as chiral stationary phases for open tubular column chromatography (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 232-237 
    Details
    ISSN: 0899-0042
    Keywords: enantiomer ; supercritical fluid chromatography (SFC) ; gas chromatography (GC) ; resolution ; polymer ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of cellulose-based stationary phases for chiral separations has been extended to open tubular column chromatography. Efficient columns were obtained by coating the capillaries with mixtures of chiral cellulose materials and conventional achiral stationary phases for gas chromatography. In this study, various siloxane and polyethylene glycol polymers were used as achiral components and mixed with different substituted benzoylcellulose derivatives as chiral components. Systematic investigations were carried out to determine the optimal ratio for the components of the stationary phase. Depending on the chromatographic mode - gas chromatography (GC) or supercritical fluid chromatography (SFC) - the stationary phases were found to behave differently. The applicability of the technique was demonstrated by the resolution of various racemic compounds. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530050408
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  • 4
    Electronic Resource
    Electronic Resource
    Separation of the enantiomers of some racemic nonsteroidal aromatase inhibitors and barbiturates by capillary electrophoresis (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 516-526 
    Details
    ISSN: 0899-0042
    Keywords: chiral ; cyclodextrin ; drug ; electrophoresis ; micellar electrokinetic ; resolution ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-performance capillary electrophoresis (HPCE) and micellar electrokinetic capillary chromatography (MECC) were applied to the resolution of racemic nonsteroidal antiaromatase drugs and intermediates. Successful results were obtained in both modes using α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD), or 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD) as chiral selectors. Depending on the structure of the solute, one of the cyclodextrins was generally better suited for resolution of the racemate. The basic solutes were analyzed under HPCE conditions, whereas the nonionizable compounds such as glutethimide (Doriden®) were analyzed in MECC mode. For the azole-type antiaromatase Fadrozole, both HPCE and MECC modes could be used to achieve the separation of the enantiomers. The influence of experimental factors such as pH, the presence of organic modifier, temperature, the micelle concentration, and the concentration of the chiral selector is also discussed on the basis of the results obtained with some chiral barbiturates. The possibility of analyzing the enantiomers directly in plasma samples was also demonstrated. © 1993 Wiley-Liss, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530050708
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  • 5
    Electronic Resource
    Electronic Resource
    Chiral discrimination of the enantiomers of δ-phenyl-δ-valerolactone by cellulose triacetate: A chromatographic and microcalorimetric study of the thermodynamics (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 538-544 
    Details
    ISSN: 0899-0042
    Keywords: CTA I ; chiral recognition ; enthalpy of complexation ; titration ; interaction sites ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The resolution of racemic δ-phenyl-δ-valerolactone by chromatography on cellulose triacetate CTA I results in one of the best separations of optical antipodes observed so far on this chiral stationary phase. The thermodynamics of the stereoselective interaction of the enantiomers of δ-phenly-δ-valerolactone have been studied by chromatography at different temperatures and by direct microcalorimetric investigations of the complexation with CTA I. This analysis suggests that the separation process is mainly controlled thermodynamically and that kinetic effects, if any, play a minor role. Microcalorimetric titration experiments indicate that specific (optimum) complexation sites on CTA I for the stronger retained enantiomer of δ-phenly-δ-valerolactone are rapidly saturated, whereas the first eluted enantiomer seems to interact much less selectively with defined interaction sites on the chiral polymer matrix. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530050710
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  • 6
    Electronic Resource
    Electronic Resource
    Chromatographic properties of composite chiral stationary phases based on cellulose derivatives (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 7 (1995), S. 425-433 
    Details
    ISSN: 0899-0042
    Keywords: racemate ; enantiomer ; HPLC ; elution order ; drugs ; agrochemicals ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral stationary phases (CSPs) prepared by mixing together two different cellulose derivatives, before or after being coated on macroporous silica gel, were developed in order to determine the mutual influence of two different polymers on global chiral recognition capacity. The chromatographic properties of these CSPs were evaluated using a wide range of racemic test solutes. The mixing method does not significantly affect the enantioselectivities. The composite CSPs obtained by cocoating of two different cellulose derivatives on silica generally exhibit chiral recognition capacities intermediate between those of the two individual phases, and thus broadening the application range of a single column. These results indicate that the simultaneous coating of two different cellulose derivatives does not significantly alter the optical resolution power of each chiral material and are discussed in relationship with the supramolecular structure of the polymeric stationary phases. © 1995 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530070607
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  • 7
    Electronic Resource
    Electronic Resource
    New chiral fluoroanthryl derivatives: Resolution of the enantiomers by chromatography on cellulose esters and their evaluation as chiral solvating agents in NMR spectroscopy (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 3 (1991), S. 177-182 
    Details
    ISSN: 0899-0042
    Keywords: cellulose triacetate ; tribenzoylcellulose ; methylbenzoylcellulose ; chiral phase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,2,2-Trifluoro-1-(9-anthryl)ethanol (TFAE) has now been widely used as a powerful chiral solvating agent for NMR spectroscopy. In connection with the development of a new general synthesis of halogenoalkylalkanols, starting from the corresponding ketone or aldehyde, we synthesized some halogenoalkyl-1-(9-anthryl)methanol derivatives liable to work as chiral solvating agents. The racemic anthryl derivatives were preparatively resolved into their corresponding enantiomers by chromatography on triacetyl cellulose (CTA I) or on meta-methylbenzoyl cellulose beads as chiral stationary phases. Their effectiveness as chiral solvating agents was measured as the magnitude of the splitting induced in the 1H-NMR spectra of 1-phenylethylamine and of (1-phenylethyl)methyl ether in comparison with splitting caused by TFAE. While TFAE induced the largest splitting for 1-phenylethylamine, 2,2,3,3,3-pentafluoro-1-(9-anthryl)propanol 2 was more effective in the case of (1-phenylethyl)methyl ether, pointing out that depending on the substrate, other derivatives of the TFAE type can be very useful as chiral solvating agents.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530030307
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  • 8
    Electronic Resource
    Electronic Resource
    Benzoyl cellulose beads in the pure polymeric form as a new powerful sorbent for the chromatographic resolution of racemates (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 3 (1991), S. 43-55 
    Details
    ISSN: 0899-0042
    Keywords: beads ; polymer ; enantiomer ; chiral phase ; interaction ; alcohol ; diol ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cellulose-based stationary phases are known to be very efficient and versatile chiral sorbents for the chromatographic resolution of racemates. Except for microcrystalline cellulose triacetate (CTA I), basically all other cellulose-based phases have been prepared by coating of ca. 20% weight polymer on a wide pore silica gel used as a carrier. In this work we describe the preparation of benzoylcellulose (TBC) beads in the pure polymeric form (without inorganic carrier) from an emulsion of the organic polymer. The new material has been fully characterized and used as a chiral stationary phase for the resolution of various classes of racemic compounds such as benzylic alcohols or acetate derivatives of aliphatic alcohols and diols. The structural variety of the separated solutes as well as the irrational influence of the aromatic substituent in different classes of aryl compounds suggest that multiple interaction sites are involved in the complexation, making a prediction of the separation difficult. The benzoyl cellulose beads exhibit a very high loading capacity, which is particularly useful for preparative purposes as demonstrated for selected examples.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530030109
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  • 9
    Electronic Resource
    Electronic Resource
    Analytic and preparative resolution of recemic γ- and δ-lactones by chromatography on cellulose triacetate. Relationship between elution order and absolute configuration (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1569-1582 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantiomers of various chiral five- and six-membered-ring lactones, Which are important classes of compounds (flavour and Pheromone components, key intermediates in the synthesis of biologically active substances) have been separated chromatographically on the chiral phase cellulose triacetate, crystallographic form I (CTAI). For different series of five-membered-ring lactones, relationships have been found between the elution order of the enantiomers and their absolute configuration. Preparative resolutions of γ-Phenyl-γ-butyrolactone (1) and of the Pheromone component 5b have been carried out to demonstrate the applicability of the method to g-scale separations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700615
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  • 10
    Electronic Resource
    Electronic Resource
    Template-Assembled Synthetic Proteins (TASP). Cyclic Templates with Incorporated Turn-Inducing Mimics (1993)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 76 (1993), S. 1539-1563 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 8-amino-5,6,7,8-tetrahydronaphth-2-oic acid (1), 8-(aminomethyl)-5,6,7,8-tetrahydronaphth-2-oic acid (2), and 8-(aminomethyl)naphth-2-oic acid (3) were synthesized in their protected forms as turn-inducing dipeptide mimics. Two of them (2 and 3) were incorporated into a novel type of cyclic, peptide-based structures (see 21 and 34-36) designed as templates for the synthesis of TASP molecules.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19930760414
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