Design, synthesis, and discovery of 5-piperazinyl-1,2,6,7-tetrahydro-5H-azepino[3,2,1-hi]indol-4-one derivatives: A novel series of mixed dopamine D<SUB>2</SUB>/D<SUB>4</SUB> receptor antagonist

5-Piperazinyl-1,2,6,7-tetrahydro-5H-azepino[3,2,1-hi]indol-4-one derivatives were designed, synthesized, and identified as a new series of mixed dopamine D2/D4 receptor antagonists. This series featured a rigid tricyclic ring system as an important pharmacophore core structure for high binding affinity. Molecular modeling studies are also described