4-Chloro-1-butanol (I) is protected as the tetrahydropyranyl ether (III) by treatment with dihydropyran (II) in the presence of pyridinium p-toluenesulfonate (PPTS). Alkylation of the sodium derivative of phenothiazine (IV) with chloride (III) yields adduct (V), which is subsequently deprotected to alcohol (VI) with PPTS in MeOH-THF. The free alcohol (VI) is then chlorinated to (VII) by using SOCl2 in benzene. Finally, condensation of chloride (VII) with pyrrolidine (VIII) in THF at 100 C in a sealed tube provides the title compound.