SUMMARYProcedures for the preparation of perphenazine-d and -d , and N-deshydroxyeth,ylperphenazine-d4 and -d 2ire 6 descriged. side chain by treatment of the appropriate ester o r imide with lithium aluminum deuteride. The y-carbon of the propyl group was labelled with two deuterium atoms by reduction of 2 -chloro-l0-(2-methoxycarbonylethyl)-l0H-phenothiazine, while four deuterium atoms were incorporated into the piperazine ring by reduction of 2-chloro-10-[3-(3,5-dioxo-l-piperazinyl)-propyl] -10H-phenothiazine.