New Pyrimido[5,4-<i>b</i>]indoles as Ligands for α<sub>1</sub>-Adrenoceptor Subtypes
作者:Giuseppe Romeo、Luisa Materia、Fabrizio Manetti、Alfredo Cagnotto、Tiziana Mennini、Ferdinando Nicoletti、Maurizio Botta、Filippo Russo、Kenneth P. Minneman
DOI:10.1021/jm0307741
日期:2003.7.1
A new series of compounds were designed as structural analogues of the alpha(1)-AR ligand RN5 (4), characterized by a tricyclic 5H-pyrimido[5,4-b]indole-(1H,3H)2,4-dione system connected through an alkyl. chain to a phenylpiperazine (PP) moiety. These compounds were synthesized and tested in binding assays on human alpha(1A)-AR, alpha(1B)-AR, and alpha(1D)-AR subtypes expressed in HEK293 cells. Several structural modifications were performed on the PP moiety, the tricyclic system, and the connecting alkyl chain. Many of the new molecules showed a preferential affinity for the alpha(1D)-AR subtype. Some compounds, including 39 and 40, displayed substantial alpha(1D)-AR selectivity with respect to alpha(1A)-AR, alpha(1B)-AR, serotonergic 5-HT1A, 5-HT1B, 5-HT2A, and dopaminergic D-1 and D-2 receptors. Two conformationally rigid analogues of 4, useful for studying the architecture of the receptor/ligand complex, were also prepared and tested. A subset of the new compounds was then used to evolve a preliminary pharmacophore model for alpha(1D)-AR antagonists, based on a more generalized model we had developed for alpha(1)-AR antagonists. This new model rationalized the relationships between structural properties and biological data of the pyrimido[5,4-b]indole compounds, as well as other compounds.