Abstract 7, 8-Dihydroxychlorpromazine and 2-chloro-7, 8-dihydroxyphenothiazine were converted to the corresponding 7, 8-dioxo compounds by oxidation with tetrachloro-o- quinone. Spectral properties indicate that the 7, 8-dioxo compounds exist in zwitterionic forms reminiscent of aminochromes. The 7, 8-dioxochlorpromazine is proposed as a possible metabolite of chlorpromazine.
