Clinical data
Routes of
ATC code
  • none
Legal status
Legal status
  • In general: uncontrolled
  • 2-{4-[4-(4-chloro-1H-pyrazol-1-yl)butyl]piperazin-1-yl}pyrimidine
CAS Number
PubChem CID
CompTox Dashboard (EPA)
Chemical and physical data
Molar mass320.83 g·mol−1
3D model (JSmol)
  • Clc1cn(nc1)CCCCN3CCN(c2ncccn2)CC3

Lesopitron (E-4424) is a selective full agonist of the 5-HT1A receptor which is structurally related to the azapirones.[1] In 2001 it was under development by Esteve as an anxiolytic for the treatment of generalized anxiety disorder (GAD).[2][3] It made it to phase II clinical trials but was apparently discontinued as no new information on lesopitron has surfaced since.[2][3]

See also


  1. ^ Haj-Dahmane S, Jolas T, Laporte AM, et al. (April 1994). "Interactions of lesopitron (E-4424) with central 5-HT1A receptors: in vitro and in vivo studies in the rat". European Journal of Pharmacology. 255 (1–3): 185–96. doi:10.1016/0014-2999(94)90097-3. PMID 8026543.
  2. ^ a b Micheli F (February 2001). "Lesopitron (Esteve)". IDrugs: The Investigational Drugs Journal. 4 (2): 218–24. PMID 16032484.
  3. ^ a b Fresquet A, Sust M, Lloret A, et al. (February 2000). "Efficacy and safety of lesopitron in outpatients with generalized anxiety disorder". The Annals of Pharmacotherapy. 34 (2): 147–53. doi:10.1345/aph.19041. PMID 10676820.