A mixture of 155 parts of 2-chloro-10-(γ-chloropropyl)phenothiazine, 75 parts
of sodium iodide, 216 parts of piperazine and 2,000 parts of butanone is
refluxed for 8 hours, concentrated and extracted with dilute hydrochloric acid.
The extract is rendered alkaline by addition of dilute potassium carbonate and
extracted with ether. This ether extract is washed with water, dried over
anhydrous potassium carbonate, filtered and evaporated. Vacuum distillation
at 0.1 mm pressure yields 2-chloro-10-(γ-piperazinopropyl)phenothiazine at
about 214°C to 218°C.
A mixture of 50 parts of the distillate, 25.6 parts of β-bromoethyl acetate,
10.7 parts of potassium carbonate and 400 parts of toluene is stirred at reflux
temperature for 16 hours. The mixture is heated with water. The organic layer
is separated, washed with water and extracted with dilute hydrochloric acid.
The resulting extract is washed with benzene, rendered alkaline and extracted
with benzene. The resulting benzene solution is dried over anhydrous
potassium carbonate, filtered and concentrated. The residue is dissolved in
300 parts of ethanol and treated with 2.2 equivalents of a 25% solution of
anhydrous hydrochloric acid in 2-propanol. The resulting crystals are
recrystallized from 400 parts of ethanol and 10 parts of water. The
dihydrochloride of N-(β-acetoxyethyl)-N'-[γ-(2'-chloro-10'-
phenothiazine)propyl]piperazine melts unsharply at about 200°C to 230°C.
