7-(3-Buten-1-yloxy)-3,4-dihydro-2(1H)-quinolinone-d6 is deuterium labeled 7-(3-Buten-1-yloxy)-3,4-dihydro-2(1H)-quinolinone (B694170). 7-(3-Buten-1-yloxy)-3,4-dihydro-2(1H)-quinolinone is an impurity of Aripiprazole (A771000), a selective dopamine D2-receptor antagonist with dopamine autoreceptor agonist activity.