Chemical structure of Thioproperazine
Clinical data
Trade namesMajeptil
ATC code
Legal status
Legal status
  • N,N-dimethyl-10-[3-(4-methylpiperazin-1-yl)propyl]-10H-phenothiazine-2-carboxamide
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.005.695 Edit this at Wikidata
Chemical and physical data
Molar mass446.63 g·mol−1
3D model (JSmol)
  • CN1CCN(CC1)CCCN2C3=CC=CC=C3SC4=C2C=C(C=C4)S(=O)(=O)N(C)C
  • InChI=1S/C22H30N4O2S2/c1-23(2)30(27,28)18-9-10-22-20(17-18)26(19-7-4-5-8-21(19)29-22)12-6-11-25-15-13-24(3)14-16-25/h4-5,7-10,17H,6,11-16H2,1-3H3

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.[2][3][4][5] Majeptil is available in 10 mg tablets.[6]

Side effects


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.

Drug interactions

Medications for allergies (e.g., Benadryl diphenhydramine), certain medications for sleep (e.g., lorazepam, zopiclone), certain medications for pain (e.g., fentanyl), and Antiparkinson medications can increase the sedative effect of thioproperazine and can be potentially dangerous when used together.


Thieme Synthesis:[8] Patents (Ex 3):[9][10][11]

Thioether formation between 2-Aminothiophenol (1) and 4-Chloro-N,N-Dimethyl-3-Nitrobenzenesulfonamide [137-47-3] (2) gives 4-(2-aminophenyl)sulfanyl-N,N-dimethyl-3-nitrobenzenesulfonamide [5510-56-5] (3). Sandmeyer reaction with cuprous bromide [7787-70-4] gave 4-[(2-Bromophenyl)-thio]-N,N'-dimethyl-3-nitro-benzenesulfonamide [5510-58-7] (4). 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.


  1. ^ Anvisa (2023-03-31). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 2023-04-04). Archived from the original on 2023-08-03. Retrieved 2023-08-16.
  2. ^ Index Nominum 2000: International Drug Directory. Taylor & Francis. 2000. pp. 1019–. ISBN 978-3-88763-075-1.
  3. ^ Morton IK, Hall JM (6 December 2012). Concise Dictionary of Pharmacological Agents: Properties and Synonyms. Springer Science & Business Media. pp. 272–. ISBN 978-94-011-4439-1.
  4. ^ "Phenothiazines (Systemic)".
  5. ^ "Thioproperazine - Oral". Retrieved 2018-09-16.
  6. ^ "Thioproperazine". Retrieved 2018-09-16.
  7. ^ "Schizophrenia Society of Ontario - Majeptil (thioproperazine)". Retrieved 2018-09-16.
  8. ^ Shavyrina VV, Zhuravlev SV, Vikhlyaev YI, Klygul' TA, Slyn'ko ÉI (1974). "Synthesis and comparison of activity of 2- and 3-dimethylsulfamidophenothiazine derivatives". Pharmaceutical Chemistry Journal. 8 (5): 286–290. doi:10.1007/BF00771334. S2CID 22229797.
  9. ^ , GB 814512  (1959 to Rhone Poulenc SA).
  10. ^ , GB 813025  (1959-05-06 to Rhone Poulenc Sa).
  11. ^ Robert Michel Jacob, Gilbert Louis Regnier, DE 1088964  (1960 to Rhone Poulenc Sa).