4-(2,3-Dichlorophenyl)-1-piperazinecarboxylic Acid 1,1-Dimethylethyl Ester-d8 is an intermediate used in the synthesis of Aripiprazole-d8 (A771002), which is a deuterated version of Aripiprazole, a selective dopamine D2-receptor antagonist with dopamine autoreceptor agonist activity.