- Evaluation of the Edman degradation product of vancomycin bonded to core-shell particles as a new HPLC chiral stationary phase
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A modified macrocyclic glycopeptide-based chiral stationary phase (CSP), prepared via Edman degradation of vancomycin, was evaluated as a chiral selector for the first time. Its applicability was compared with other macrocyclic glycopeptide-based CSPs: TeicoShell and VancoShell. In addition, another modified macrocyclic glycopeptide-based CSP, NicoShell, was further examined. Initial evaluation was focused on the complementary behavior with these glycopeptides. A screening procedure was used based on previous work for the enantiomeric separation of 50 chiral compounds including amino acids, pesticides, stimulants, and a variety of pharmaceuticals. Fast and efficient chiral separations resulted by using superficially porous (core-shell) particle supports. Overall, the vancomycin Edman degradation product (EDP) resembled TeicoShell with high enantioselectivity for acidic compounds in the polar ionic mode. The simultaneous enantiomeric separation of 5 racemic profens using liquid chromatography-mass spectrometry with EDP was performed in approximately 3?minutes. Other highlights include simultaneous liquid chromatography separations of rac-amphetamine and rac-methamphetamine with VancoShell, rac-pseudoephedrine and rac-ephedrine with NicoShell, and rac-dichlorprop and rac-haloxyfop with TeicoShell.
- Hellinghausen, Garrett,Lopez, Diego A.,Lee, Jauh T.,Wang, Yadi,Weatherly, Choyce A.,Portillo, Abiud E.,Berthod, Alain,Armstrong, Daniel W.
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p. 1067 - 1078
(2018/08/01)
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- Structure-activity relationships for a novel series of citalopram (1-(3-(dimethylamino)propyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5- carbonitrile) analogues at monoamine transporters
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(±)-Citalopram (1, 1-(3-(dimethylamino)propyl)-1-(4-fluorophenyl)-1, 3-dihydroisobenzofuran-5-carbonitrile), and its eutomer, escitalopram (S-(+)-1) are selective serotonin reuptake inhibitors (SSRIs) that are used clinically to treat anxiety and depression. To further explore structure-activity relationships at the serotonin transporter (SERT), a series of (±)-4- and 5-substituted citalopram analogues were designed, synthesized, and evaluated for binding at the SERT, dopamine transporter (DAT) and norepinephrine transporter (NET) in native rodent tissue. Many of these analogues showed high SERT binding affinities (Ki = 1-40 nM) and selectivities over both NET and DAT. Selected enantiomeric pairs of analogues were synthesized and both retained enantioselectivity as with S- and R-1, wherein S > R at the SERT. In addition, the enantiomeric pairs of 1 and 5 were tested for binding at the homologous bacterial leucine transporter (LeuT), wherein low affinities and the absence of enantioselectivity suggested distinctive binding sites for these compounds at SERT as compared to LeuT. These novel ligands will provide molecular tools to elucidate drug-protein interactions at the SERT and to relate those to behavioral actions in vivo.
- Zhang, Peng,Cyriac, George,Kopajtic, Theresa,Zhao, Yongfang,Javitch, Jonathan A.,Katz, Jonathan L.,Newman, Amy Hauck
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experimental part
p. 6112 - 6121
(2010/11/16)
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- Response to the comments by Elati et al. in response to our article examining one of their previous articles
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This reply highlights and discusses what we observe as internal inconsistencies in the data and analysis presented by Elati and coauthors in conjunction with their resolution protocols, as well as inconsistencies between their original manuscript, the ass
- Dancer, Robert James,Lopez De Diego, Heidi Lopez
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experimental part
p. 38 - 43
(2010/04/22)
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- PROCESS FOR THE PREPARATION OF ESCITALOPRAM OR ITS ACID ADDITION SALTS
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The present invention relates to Formula (I), a process for the preparation of highly pure Escitalopram or its acid addition salts which comprises: a) reacting racemic diol or its ester derivative (III) with an optically active acid and at least one solvent to get enantiomerically pure diastereomer (IIIA); b) separating the enantiomerically pure diastereomer (IIIA) from its optically active acid salt by treating it with base and followed by stereo selective cyclization; c) separating the Escitalopram base.
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Page/Page column 13-15
(2010/11/24)
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- PREPARATION OF ESCITALOPRAM
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Enantiomerically enriched citalopram is prepared by methylating enantiomerically enriched didesmethylcitalopram, obtained by directly resolving racemic didesmethylcitalopram using a chiral acid.
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Page/Page column 29-30
(2008/06/13)
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