Title: Flesinoxan
CAS Registry Number: 98206-10-1
CAS Name: N-[2-[4-[(2R)-2,3-Dihydro-2-(hydroxymethyl)-1,4-benzodioxin-5-yl]-1-piperazinyl]ethyl]-4-fluorobenzamide
Additional Names: (+)-(S)-p-fluoro-N-[2-[4-[2-(hydroxymethyl)-1,4-benzodioxan-5-yl]-1-piperazinyl]ethyl]benzamide
Molecular Formula: C22H26FN3O4
Molecular Weight: 415.46
Percent Composition: C 63.60%, H 6.31%, F 4.57%, N 10.11%, O 15.40%
Literature References: Serotonin (5-HT1A)-receptor agonist; phenylpiperazine derivative. Prepn: J. Hartog et al., EP 138280; eidem, US 4833142 (1985, 1989 both to Duphar). Synthesis and resolution of enantiomers: M. D. Ennis, N. B. Ghazal, Tetrahedron Lett. 33, 6287 (1992). GC determn in plasma and urine: M. P. van Berkel et al., Methodol. Surv. Biochem. Anal. 18, 209 (1988). Pharmacology: J. Schipper et al., Hum. Psychopharmacol. 6, S53 (1991). Clinical evaluation in depression: P. Grof et al., Int. Clin. Psychopharmacol. 8, 167 (1993).
Properties: [a]D +26° (c = 1 in methanol).
Optical Rotation: [a]D +26° (c = 1 in methanol)
Derivative Type: Hydrochloride
CAS Registry Number: 98205-89-1
Manufacturers' Codes: DU-29373
Molecular Formula: C22H26FN3O4.HCl
Molecular Weight: 451.92
Percent Composition: C 58.47%, H 6.02%, F 4.20%, N 9.30%, O 14.16%, Cl 7.84%
Properties: mp 184.5-185.5°. Also reported as crystals from ethanol/ether, mp 183.0-184.0° (Ennis). [a]D +25° (c = 1 in methanol). Freely sol in water; sparingly sol in ethanol.
Melting point: mp 184.5-185.5°; mp 183.0-184.0° (Ennis)
Optical Rotation: [a]D +25° (c = 1 in methanol)
Therap-Cat: Anxiolytic.
Keywords: Anxiolytic; Arylpiperazines; Serotonin Receptor Agonist.
Flindersine Flocoumafen Floctafenine Flomoxef Flonicamid

Systematic (IUPAC) name
Clinical data
Legal status Uncontrolled
Routes Oral
CAS number 98206-10-1
ATC code None
PubChem CID 57347
ChemSpider 51700
UNII 3V574S89E1 YesY
KEGG D02568
Chemical data
Formula C22H26FN3O4 
Mol. mass 415.458 g/mol

Flesinoxan (DU-29,373) is a potent and selective 5-HT1A receptor partial/near-full agonist of the phenylpiperazine class.[1][2][3] Originally developed as an antihypertensive agent,[1][2][4] it was later found to possess antidepressant and anxiolytic effects in animals.[5][6] As a result, it was investigated in human clinical trials for the treatment of major depressive disorder and generalized anxiety disorder and was found to have robust efficacy with very high tolerability,[7][8] but for unclear reasons development was halted and it was never marketed. In patients it enhances REM sleep latency, decreases body temperature, and increases ACTH, cortisol, prolactin, and growth hormone secretion.[8][9]