Thioproperazine, sold under the brand name Majeptil, is a typical antipsychotic of the phenothiazine group which is used as a tranquilizer, antiemetic, sedative, and in the treatment of schizophrenia and manic phase of bipolar disorder.

[6] Common[7] Rare but potentially serious adverse effects Elderly individuals with dementia-related psychosis treated with antipsychotic medication are at an increased risk of death compared to individuals not receiving antipsychotics.

Bechamp reduction gave 3-Amino-4-((2-bromophenyl)thio)-N,N-dimethylbenzenesulphonamide [5592-64-3] (5).

Goldberg reaction completed the formation of the phenothiazine ring and gave N,N-dimethyl-10H-phenothiazine-2-sulfonamide [1090-78-4] (6).

Attachment of the sidechain by sodamide reaction with 1-(3-Chloropropyl)-4-Methylpiperazine [104-16-5] (7) completes the synthesis of Thioproperazine (8), respectively.