Synthesis and In Vitro Evaluation of Novel Dopamine Receptor D(2) 3,4-dihydroquinolin-2(1H)-one Derivatives Related to Aripiprazole

In this pilot study, a series of new 3,4-dihydroquinolin-2(1H)-one derivatives as potential dopamine receptor D(2) (D(2)R) modulators were synthesized and evaluated in vitro. The preliminary structure–activity relationship disclosed that compound 5e exhibited the highest D(2)R affinity among the newly synthesized compounds. In addition, 5e showed a very low cytotoxic profile and a high probability to cross the blood–brain barrier, which is important considering the observed affinity. However, molecular modelling simulation revealed completely different binding mode of 5e compared to USC-D301, which might be the culprit of the reduced affinity of 5e toward D(2)R in comparison with USC-D301.