3-Alkyl- and 3-amido-isothiazoloquinolin-4-ones as ligands for the benzodiazepine site of GABA(A) receptors.
- Centre for Analysis and Synthesis
Publishing year: 2011-10-17
Publication/Series: Bioorganic & Medicinal Chemistry Letters
Document type: Journal article
Based on a pharmacophore model of the benzodiazepine binding site of the GABA(A) receptors, developed with synthetic flavones and potent 3-carbonylquinolin-4-ones, 3-alkyl- and 3-amido-6-methylisothiazoloquinolin-4-ones were designed, prepared and assayed. The suggestion that the interaction between the hydrogen bond donor site H1 with the 3-carbonyl oxygen in 3-carbonylquinolin-4-ones can be replaced by an interaction between H1 and N-2 in the isothiazoloquinolin-4-ones, was confirmed. As with the 3-carbonylquinolin-4-ones, the length of the chain in position 3 is critical for an efficient interaction with the lipophilic pockets of the pharmacophore model. The most potent 3-alkyl derivative, 3-pentyl-6-methylisothiazoloquinolin-4-one, has an affinity (K(i) value) for the benzodiazepine binding site of the GABA(A) receptors of 13nM. However, by replacing the 3-pentyl with a 3-butyramido group an even more potent compound was obtained, with a K(i) value of 2.8nM, indicating that the amide function facilitates additional interactions with the binding site.
- Organic Chemistry
- ISSN: 1090-2120