Synthesis, cannabinoid receptor affinity, and molecular modeling studies of substituted 1-aryl-5-(1H-pyrrol-1-yl)-1H-pyrazole-3-carboxamides.

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Silvestri R, Cascio MG, La Regina G, Piscitelli F, Lavecchia A, Brizzi A, Pasquini S, Botta M, Novellino E, Di Marzo V, Corelli F

Synthesis, cannabinoid receptor affinity, and molecular modeling studies of substituted 1-aryl-5-(1H-pyrrol-1-yl)-1H-pyrazole-3-carboxamides.

J Med Chem. 2008 Mar 27;51(6):1560-76. doi: 10.1021/jm070566z. Epub 2008 Feb 23.

PubMed ID

18293908 [ View in PubMed

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Abstract

The new 1-phenyl-5-(1 H-pyrrol-1-yl)pyrazole-3-carboxamides were compared with the reference compounds AM251 and SR144528 for cannabinoid hCB 1 and hCB 2 receptor affinity. Compounds bearing 2,4-dichlorophenyl or 2,4-difluorophenyl groups at position 1 and 2,5-dimethylpyrrole moiety at position 5 of the pyrazole nucleus were generally more selective for hCB 1. On the other hand, the N-cyclohexyl group at the 3-carboxamide was the determinant for the hCB 2 selectivity, in particular when a 3,4-dichlorophenyl group was also present at position 1. Compound 26 was the most selective ligand for the hCB 1 receptor ( K i (CB 2)/ K i (CB 1) = 140.7). Derivative 30, the most potent hCB 1 ligand ( K i = 5.6 nM), was equipotent to AM251 and behaved as an inverse agonist in the cAMP assay (EC 50 approximately 1 nM). The carbonyl oxygen of both 26 and 30 formed a H-bond with K3.28(192), while the substituents at the nitrogen fitted in a pocket formed by lipophilic residues. This H-bonding interaction was proposed to account for the high affinity for receptors' inactive state and the inverse agonist activity.

DrugBank Data that Cites this Article

Binding Properties

Drug	Target	Property	Measurement	pH	Temperature (°C)
Rimonabant	Cannabinoid receptor 1	Ki (nM)	12	7.4	30	Details