Synthesis and pharmacological properties of 2- and 2,3-substituted quinuclidines

Yanina, A. D.; Trubitsyna, T. K.; Mikhlina, E. E.; Yakhontov, L. N.

doi:10.1007/bf00758757

Cited by 2 publications

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“…The pyrazole ( 3 ) was synthesized (Scheme ) starting from 3-quinuclidinone ( 4 ). Condensation with 4-chlorobenzaldehyde gave the unsaturated ketone 5 , which on treatment with hydrazine and base ring opened to give pyrazole 6 . Alkylation with 4-chlorobenzyl chloride gave 3 .…”

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confidence: 99%

5-(4-Chlorophenyl)-4-methyl-3-(1-(2- phenylethyl)piperidin-4-yl)isoxazole: A Potent, Selective Antagonist at Human Cloned Dopamine D4 Receptors

et al. 1996

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confidence: 99%

5-(4-Chlorophenyl)-4-methyl-3-(1-(2- phenylethyl)piperidin-4-yl)isoxazole: A Potent, Selective Antagonist at Human Cloned Dopamine D4 Receptors

et al. 1996

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“…A similar effect is seen when the benzene ring is replaced with a thiophene (16). The three pyridyl isomers (17)(18)(19) have similar profiles, with a small reduction in binding to hD4 receptors when compared to the benzene ring, along with a smaller reduction in hD2 affinity. None of these changes show benefit over the (4-chlorophenyl)pyrazole present in the lead.…”

Section: Discussionmentioning

confidence: 96%

“…The pyrazole 3 was synthesized (Scheme ) starting from 3-quinuclidinone ( 38 ). Condensation with 4-chlorobenzaldehyde gave the unsaturated ketone 39 , which on treatment with hydrazine and base ring opened to give pyrazole 4 . Alkylation with 4-chlorobenzyl chloride gave the lead compound 3 .…”

Section: Chemistry and Biologymentioning

confidence: 99%

4-Heterocyclylpiperidines as Selective High-Affinity Ligands at the Human Dopamine D4 Receptor

et al. 1997

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5-(4-Chlorophenyl)-3-(1-(4-chlorobenzyl)piperidin-4-yl)pyrazole (3) was identified from screening of the Merck sample collection as a human dopamine D4 (hD4) receptor ligand with moderate affinity (61 nM) and 4-fold selectivity over human D2 (hD2) receptors. Four separate parts of the molecule have been examined systematically to explore structure-activity relationships with respect to hD4 affinity and selectivity over other dopamine receptors. It was found that the 4-chlorophenyl group attached to the pyrazole is optimal, as is the 4-substituted piperidine. The lipophilic group on the basic nitrogen is more amenable to change, with the optimal group found to be a phenethyl. The aromatic heterocyle can be altered to a number of different groups, with isoxazoles and pyrimidines showing improved affinities. This heterocycle can also be advantageously alkylated, improving the selectivity of the compounds over D2 receptors. It is hypothesized that the conformation around the bond joining the aromatic heterocycle to the piperidine is important for D4 affinity, based on crystal structures of isoxazoles (29 and 30) and on a conformationally constrained compound (28). Putting all the favorable changes together led to the discovery that 5-(4-chlorophenyl)-4-methyl-3-(1-(2-phenylethyl)piperidin-4-yl)iso xazole (36) is a nanomolar antagonist at human dopamine D4 receptors with > 500-fold selectivity over hD2 and > 200-fold selectivity over hD3. Compound 36 is an antagonist of hD4 receptors with good oral bioavailability of 38%, a half life of 2 h, and brain levels 10-fold higher than plasma levels.

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Synthesis and pharmacological properties of 2- and 2,3-substituted quinuclidines

Cited by 2 publications

References 0 publications

5-(4-Chlorophenyl)-4-methyl-3-(1-(2- phenylethyl)piperidin-4-yl)isoxazole: A Potent, Selective Antagonist at Human Cloned Dopamine D4 Receptors

5-(4-Chlorophenyl)-4-methyl-3-(1-(2- phenylethyl)piperidin-4-yl)isoxazole: A Potent, Selective Antagonist at Human Cloned Dopamine D4 Receptors

4-Heterocyclylpiperidines as Selective High-Affinity Ligands at the Human Dopamine D4 Receptor

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