Abstract
The synthesis and pharmacology of two potential glutamic acid receptor ligands are described. Preparation of the bicyclic 3-hydroxy-delta2-isoxazoline-cyclopentane derivatives (+/-)-7 and (+/-)-8 was accomplished via 1,3-dipolar cycloaddition of bromonitrile oxide to suitably protected 1-amino-cyclopent-3-enecarboxylic acids. Their structure was established using a combination of 1H NMR spectroscopy and molecular mechanics calculations carried out on the intermediate cycloadducts (+/-)-11 and (+/-)-12. Amino acid derivatives (+/-)-7 and (+/-)-8 were assayed at ionotropic and metabotropic glutamic acid receptor subtypes and their activity compared with that of trans-ACPD and cis-ACPD. The results show that the replacement of the omega-carboxylic group of the model compounds with the 3-hydroxy-delta2-isoxazoline moiety abolishes or reduces drastically the activity at the metabotropic glutamate receptors. Conversely, on passing from cis-ACPD to derivative (+/-)-8, the agonist activity at NMDA receptors is almost unaffected.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acids / chemistry
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Animals
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Binding, Competitive / drug effects
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Cerebral Cortex / drug effects
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Cyclization
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Cycloleucine / analogs & derivatives*
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Cycloleucine / chemical synthesis
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Cycloleucine / pharmacology
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Electrophysiology
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Excitatory Amino Acid Antagonists / chemical synthesis
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Excitatory Amino Acid Antagonists / pharmacology
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Glutamates / chemical synthesis*
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Glutamates / pharmacology*
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In Vitro Techniques
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Ligands
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Magnetic Resonance Spectroscopy
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Models, Molecular
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Molecular Conformation
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Rats
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Receptors, AMPA / drug effects
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Receptors, Glutamate / drug effects*
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Receptors, Kainic Acid / drug effects
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Receptors, Metabotropic Glutamate / drug effects
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Receptors, N-Methyl-D-Aspartate / drug effects
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Stereoisomerism
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gamma-Aminobutyric Acid / physiology
Substances
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Amino Acids
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Excitatory Amino Acid Antagonists
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Glutamates
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Ligands
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Receptors, AMPA
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Receptors, Glutamate
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Receptors, Kainic Acid
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Receptors, Metabotropic Glutamate
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Receptors, N-Methyl-D-Aspartate
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Cycloleucine
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1-amino-1,3-dicarboxycyclopentane
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gamma-Aminobutyric Acid