Design, synthesis and biological evaluation of bitopic arylpiperazine-hexahydro-pyrazinoquinolines as preferential dopamine D3 receptor ligands

Three series of bitobic arylpiperazine-phenyl-hexahydropyrazinoquino- lines analogues were designed, synthesizedand evaluated as a novel class of selective ligands for the dopamine D3 receptor. Compounds 15a (Ki of 11.7 ± 1.8 and 373 nM at D3 and D2, respectively), 15c (Ki of 5.49 and 264 nM at D3 and D2, respectively), 15e (Ki of 14.9 and 325 nM at D3 and D2, respectively), 15i (Ki of 13.8 and 401 nM at D3 and D2, respectively) and 15l (Ki of 13.6 and 870 nM at D3 and D2, respectively) were found to demonstrate good binding affinity and selectivity, and especially compound 15c showeda similar binding affinity and selectivity compared with the contrast drug BP897.