Structure−Selectivity Investigations of D<sub>2</sub>-Like Receptor Ligands by CoMFA and CoMSIA Guiding the Discovery of D<sub>3</sub> Selective PET Radioligands
作者:Ismail Salama、Carsten Hocke、Wolfgang Utz、Olaf Prante、Frank Boeckler、Harald Hübner、Torsten Kuwert、Peter Gmeiner
DOI:10.1021/jm0611152
日期:2007.2.8
Elucidation of the physiological role of the D-3 receptor and its distribution in the brain using positron emission tomography (PET) is hampered by the lack of bioavailable subtype selective tracer ligands. To develop appropriate D-3 radioligands, we designed an integrative procedure involving the elucidation of structural features determining D-3 selectivity over both congeners D-2 and D-4 by comparative molecular analysis. Thus, we have successfully generated CoMFA and CoMSIA models based on the affinitiy differences of a series of 79 ligands representing a broad range of selectivities. These models yielded highly significant cross-validations (q(cv)(2)(D-3/D-2) = 0.86; q(cv)(2)(D-3/D-4) = 0.92) and excellent predictions of a 16-ligand test set (r(pred)(2) = 0.79-0.93). Exploiting this information, synthesis and receptor binding studies directed us to the fluorinated lead compounds 78 and 79, featuring subnanomolar D-3 affinities and considerable selectivities over D-2 and D-4 and, subsequently, to the subtype selective PET tracers [F-18]78 and [F-18]79.