1-(3-Buten-1-yl)-4-(2,3-dichlorophenyl)-piperazine-d8 is deuterium labeled 1-(3-Buten-1-yl)-4-(2,3-dichlorophenyl)-piperazine (B694150). 1-(3-Buten-1-yl)-4-(2,3-dichlorophenyl)-piperazine is an impurity of Aripiprazole (A771000), a selective dopamine D2-receptor antagonist with dopamine autoreceptor agonist activity.