2-dimethylamino-l-propyl

The first synthesis of phenothiazine was reported by Bernthsen about 80 years ago. In the evolution of the chemistry of this heterocycle, three periods can be discerned. First, phenothiazine was of interest owing to its quinonoid derivatives—an important chapter in sulfur dye chemistry. Research work in the field of phenothiazine was then stimulated by the discovery of the anthelmintic action of unsubstituted and of some C -substituted phenothiazines. During the last two decades, the exceptional pharmacological properties of some A-substituted phenothiazines, e.g., the antihistaminic activity of promethazine, 10-(2-dimethylamino-l-propyl)phenothiazine, and particularly the psychotherapeutic action of chlorpromazine, 2-chloro-10-(3-dimethylamino-1 -propyl )phenothiazine, focused interest mainly on the synthesis and testing of a great number of compounds of this type. The phenothiazine drugs now play a very important part in chemotherapy. 

Phenothiazines are not naturally occurring substances but a number of phenothiazine derivatives have useful medicinal applications. For example, phenothiazine and some C-substituted derivatives have anthelmintic properties (i.e., the ability to destroy worms). Various N-substituted phenothiazines have important pharmacological properties. For example, promethazine [10-(2-dimethylamino-l-propyl)phenothiazine] possesses antihistaminic activity and chlorpromazine [2-chloro-10-(3-dimethylamino-l-propyl)phenothiazine] has a profound psychotherapeutic activity and is widely used, as are related phenothiazines, for the treatment of various mental illnesses. 

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