A PREFERENTIAL FOLDED CONFORMATION OF SOME BIS-(8-ISOPROPYL-ISOQUINOLINIUM) DERIVATIVES EXPLAINS STEREOSELECTIVE REDUCTION BY SODIUM BOROHYDRIDE

Dilly, Sébastien; Badarau, Eduard; Dufour, Fabien; Nistor, Iolanda; Hubert, Philippe; Seutin, Vincent; Wouters, Johan; Liégeois, Jean-François

Reference : A PREFERENTIAL FOLDED CONFORMATION OF SOME BIS-(8-ISOPROPYL-ISOQUINOLINIUM) DERIVATIV...


	Document type :	Scientific congresses and symposiums : Poster
	Discipline(s) :	Human health sciences : Pharmacy, pharmacology & toxicology Engineering, computing & technology : Computer science Physical, chemical, mathematical & earth Sciences : Chemistry
	To cite this reference:	http://hdl.handle.net/2268/169543

Title :	A PREFERENTIAL FOLDED CONFORMATION OF SOME BIS-(8-ISOPROPYL-ISOQUINOLINIUM) DERIVATIVES EXPLAINS STEREOSELECTIVE REDUCTION BY SODIUM BOROHYDRIDE
Language :	English
Author, co-author :	Dilly, Sébastien [Université de Liège - ULiège > GIGA-Neuroscience / CIRM > Pharmacologie / Chimie Pharmaceutique > >]
	Badarau, Eduard [Université de Liège - ULiège > CIRM > Chimie Pharmaceutique > >]
	Dufour, Fabien [Université de Liège - ULiège > CIRM > Chimie Pharmaceutique > >]
	Nistor, Iolanda [Université de Liège - ULiège > CIRM > Chimie Analytique > >]
	Hubert, Philippe [Université de Liège - ULiège > Département de pharmacie > Chimie analytique >]
	Seutin, Vincent [Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Pharmacologie >]
	Wouters, Johan [Université de Namur > Chimie > > >]
	Liégeois, Jean-François [Université de Liège - ULiège > Département de pharmacie > Chimie pharmaceutique >]
Publication date :	5-Jun-2014
Page number :	A0
Peer reviewed :	Yes
Audience :	International
Event name :	28èmes Journées Franco-Belges de Pharmacochimie
Event date :	5-6 Juin 2014
Event organizer :	Université de Lorraine
Event place (city) :	Metz
Event country :	France
Keywords :	[en] selectivity ; borohydride ; sterical hindrance ; conformational analysis ; X-ray crystallography ; chiral HPLC
Abstract :	[en] Small conductance Ca2+-activated K+ (SK) channels play a role in modulating the firing rate and the firing pattern of neurons [Waroux, Eur J Neurosci, 2005, 22, 3111]. A blockade of these targets could be useful for the treatment of cognitive dysfunction, neuronal hyperexcitability or dopamine related disorders [Liégeois, Curr Med Chem, 2003, 10, 625]. At the peripheral level, the inhibition of these channels was demonstrated to prevent and terminate atrial fibrillation [Diness, Circ Arrhythm Electrophysiol, 2010, 3, 380]. Moreover, SK channels might represent potential targets for a new class of anticancer agents due to their involvement in breast cancer cell migration [Potier, Mol Cancer Ther, 2006, 5, 2946]. So far, available blockers are not suitable CNS pharmacological tools being either peptides or small molecules with permanent positive charges [Liégeois, Curr Med Chem, 2003, 10, 625; Graulich, J Med Chem, 2007, 50, 5070; Badarau, Bioorg Med Chem Lett, 2011, 21, 6756]. Therefore, symmetrical bis-isoquinolinium compounds have subsequently been transformed to 1,2,3,4-tetrahydroisoquinoline analogues by using sodium borohydride leading to a diastereoisomeric mixture (figure 1) in order to obtain potential CNS-penetrating agents [Graulich, Bioorg Med Chem Lett, 2008, 18, 3440; Neny, Proceedings of the 12th International Conference on In Vivo Methods, Vancouver, Canada, 2008, 267; Koulchitsky, Acta Physiologica, 2009, 195, 670]. Resolution of these mixtures and characterization of the corresponding stereoisomers [Wouters, Eur J Med Chem, 2010, 45, 3240] are necessary before further biological evaluation. In a series of 8- isopropyl analogues, chiral resolution failed for the analogues with propyl and m-xylyl linkers since two and one peaks, respectively, were detected [Nistor, J Pharm Biomed Anal, 2013, 74, 273]. Could these results be explained by an ineffective resolution or would another phenomenon be involved? Further analysis using chiral chromatography, mass spectroscopy and circular dichroism of a sample of the propyl analogue revealed that it is a racemic mixture. X-ray cristallography and conformational analysis indicated a folded conformation of the propyl and m-xylyl analogues (figure 2) responsible for a stereoselective attack of the borohydride reagent during the reduction step. Additional 1H-NMR investigations support structural features detected by theoretical analysis.
Research centres :	Centre Interfacultaire de Recherche du Médicament - CIRM ; Giga-Neurosciences
Funders :	Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS ; SPW DGO6 PPP NEUREDGE ; Université de Liège
Name of the research project :	SK Channels
Target :	Researchers ; Professionals ; Students
Permalink :	http://hdl.handle.net/2268/169543

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