Abstract
Stereoselective synthesis of all four stereoisomers of methylated analogues 8 of the kappa-receptor agonist GR-89.696 is presented. Starting with orthogonally protected piperazine derivatives (R,R)-4 and (S,S)-4, the reaction sequence involves oxidation, reductive amination and modification of the piperazine nitrogen protective groups. The configuration of the stereocentre in alpha-position to the pyrrolidine moiety is determined by X-ray structure analysis of (R,S)-8. In receptor-binding studies with the radioligand U-69.593, the stereoisomer with (S)-configuration at both stereogenic centres (S,S)-8 displayed the highest kappa-receptor affinity with a K(i)-value of 0.67 nM.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adrenergic alpha-Agonists / chemical synthesis*
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Adrenergic alpha-Agonists / metabolism*
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Analgesics, Non-Narcotic / chemical synthesis*
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Analgesics, Non-Narcotic / metabolism*
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Animals
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Brain / cytology
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Crystallography, X-Ray
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Guinea Pigs
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Membranes / chemistry
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Piperazines / chemical synthesis*
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Piperazines / metabolism*
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Protein Binding
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Pyrrolidines / chemical synthesis*
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Pyrrolidines / metabolism*
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Radioligand Assay
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Receptors, Opioid, kappa / metabolism*
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Stereoisomerism
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Structure-Activity Relationship
Substances
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Adrenergic alpha-Agonists
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Analgesics, Non-Narcotic
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Piperazines
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Pyrrolidines
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Receptors, Opioid, kappa
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GR 89696