2-Bromo-2'-(3''-dimethylaminopropyl)-amino-4'-chlorodiphenylsulfide (10 g) is
dissolved in dimethylformamide (80 cc). To this solution is added potassium
carbonate (5 g) and copper powder (0.4 g). It is then heated under reflux for
48 hours, cooled, and the insoluble matter filtered off. After washing with
dimethylformamide (20 cc), the filtrate is taken up in distilled water (200cc).
The base formed is extracted with ether (3 times with 50 cc), the ethereal
solution is dried over sodium sulfate, the ether driven off on a water-bath and
the residue distilled. In this way there is obtained 3-chloro-10-(3'-
dimethylaminopropyl)-phenothiazine (6.4 g) which boils at 210 C to 225°C
under 0.7 mm of mercury. The hydrochloride is made by the action of ethereal
hydrogen chloride on the base dissolved in acetone; this hydrochloride melts
at 180°C
