- Molecular basis of the selective binding of MDMA enantiomers to the alpha4beta2 nicotinic receptor subtype: Synthesis, pharmacological evaluation and mechanistic studies
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The α4β2 nicotinic acetylcholine receptor (nAChR) is a molecular target of 3,4-methylenedioxymethamphetamine (MDMA), a synthetic drug also known as ecstasy, and it modulates the MDMA-mediated reinforcing properties. However, the enantioselective preference of the α4β2 nAChR subtype still remains unknown. Since the two enantiomers exhibit different pharmacological profiles and stereoselective metabolism, the aim of this study is to assess a possible difference in the interaction of the MDMA enantiomers with this nAChR subtype. To this end, we report a novel simple, yet highly efficient enantioselective synthesis of the MDMA enantiomers, in which the key step is the diastereoselective reduction of imides derived from optically pure tert-butylsulfinamide. The enantioselective binding to the receptor is examined using [3H]epibatidine in a radioligand assay. Even though the two enantiomers induced a concentration-dependent binding displacement, (S)-MDMA has an inhibition constant 13-fold higher than (R)-MDMA, which shows a Hill's coefficient not significantly different from unity, implying a competitive interaction. Furthermore, when NGF-differentiated PC12 cells were pretreated with the compounds, a significant increase in binding of [3H] epibatidine was found for (R)-MDMA, indicating up-regulation of heteromeric nAChR in the cell surface. Finally, docking and molecular dynamics studies have been used to identify the binding mode of the two enantiomers, which provides a structural basis to justify the differences in affinity from the differential interactions played by the substituents at the stereogenic centre of MDMA. The results provide a basis to explore the distinct psychostimulant profiles of the MDMA enantiomers mediated by the α4β2 nAChR subtype.
- Llabrés, Salomé,García-Ratés, Sara,Cristóbal-Lecina, Edgar,Riera, Antoni,Borrell, José Ignacio,Camarasa, Jorge,Pubill, David,Luque, F. Javier,Escubedo, Elena
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- Exploring nitrostyrene as a scaffold for a new class a of monoamine oxidase inhibitors
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With the ultimate purpose of finding out the structural features that are relevant for MAO inhibitory activity and selectivity towards MAO-B isoform, a series of compounds encompassing a β-nitrostyrene moiety was designed and the in vitro inhibitory activity was evaluated. In the present work, we report the synthesis and the pharmacological evaluation of a series of functionalized derivatives of β-methyl-β-nitrostyrene with distinct substitution patterns in the phenyl ring, namely hydroxyl, methoxy, benzyloxy and methylenedioxy. All the studied compounds were substituted in meta and para positions of the phenyl ring related to the nitrovinyl side chain. The synthesized compounds were evaluated towards both human MAO isoforms, displaying some of them activities in the low micromolar range. Particularly compound 6 (a methylenedioxy derivative) exhibits high potency and selectivity towards MAO-B.
- Reis, Joana,Oliveira, Catarina,Milhazes, Nuno,Vi?a, Dolores,Borges, Fernanda
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p. 958 - 961
(2013/02/23)
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- Synthesis and capillary electrophoretic analysis of enantiomerically enriched reference standards of MDMA and its main metabolites
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Enantiomerically-enriched (S)-3,4-methylenedioxymethamphetamine (MDMA) and its main metabolites (S)-4-hydroxy-3-methoxymethamphetamine (HMMA) and (S)-3,4-dihydroxymethamphetamine (HHMA) were prepared or unequivocal identification of the differential enantioselective metabolism of these compounds as well as for its application in the analysis of biological samples. Capillary electrophoresis with cyclodextrin derivatives and a chemical correlation of (S)-MDMA, (S)-HMMA and (S)-HHMA has been performed to assign the absolute stereochemistry of major isomers in analytical standards enriched with such enantiomers. Copyright
- Pizarro, Nieves,De la Torre, Rafael,Farre, Magi,Segura, Jordi,Llebaria, Amadeu,Joglar, Jesus
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p. 1085 - 1092
(2007/10/03)
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- Synthesis of bronchospasmolytically effective β phenylethyl aminoalkyl xanthines
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New theophylline and theobromine derivatives are synthesized from the β phenylethylaminoalkyl xanthines, whose phenyl substituent is substituted by one or two hydroxyl groups and partially also by other substituents. Different methods of synthesis are described, among them the production of the bronchospasmolytic 7 (3 [2 (3,5 dihydroxyphenyl) 2 hydroxy ethylamino] propyl) theophylline (reproterol . HCl).
- Klingler
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