title: Synthesis and pharmacology of the enantiomers of UH301: opposing interactions with 5-HT1A receptors.
abstract: The (S)-enantiomer of 5-fluoro-8-hydroxy-2-(dipropylamino) tetralin [(S)-2a; (S)-UH301] was the first reported 5-HT1A receptor antagonist. We now give a full account on the synthetic effort leading to the preparation of the racemate and the enantiomers of 2a. The crystal and molecular structure of 2a. HBr has been determined by X-ray diffraction and the absolute configuration has been deduced using statistical tests of the crystallographic R values. The unit cell is tetragonal (P4(1)2(1)2) with a = b = 13.2235(2), c = 39.560(1) A and contains two crystallographically independent molecules in each asymmetric unit. The two solid state conformers differ in the conformation of the N-propyl groups. The pharmacological characterization of the enantiomers was done by use of in vivo biochemical and behavioural assays in rats. The (R)-enantiomer of 2a is a 5-HT1A receptor agonist of low potency while (S)-2a does not exhibit any agonist properties at 5-HT1A receptors. As a consequence of the opposing effects of the enantiomers, the racemate, rac-2a, does not produce any clear-cut effects in rats. The reduced efficacy of (S)-2a as compared to the well known 5-HT1A receptor agonist 8-hydroxy-2-(dipropylamino) tetralin (1;8-OH-DPAT) may be due to the fluoro-substituent induced negative potential of the aromatic ring.
authors.affiliation: Department of Organic Pharmaceutical Chemistry, Uppsala Biomedical Centre, Uppsala University, Sweden.
authors.forename: S E
authors.initials: SE
authors.lastname: Hillver
authors.forename: L
authors.initials: L
authors.lastname: Björk
authors.forename: B B
authors.initials: BB
authors.lastname: Höök
authors.forename: L
authors.initials: L
authors.lastname: Cortizo
authors.forename: G
authors.initials: G
authors.lastname: Nordvall
authors.forename: A M
authors.initials: AM
authors.lastname: Johansson
authors.forename: A
authors.initials: A
authors.lastname: Ertan
authors.forename: I
authors.initials: I
authors.lastname: Csöregh
authors.forename: L
authors.initials: L
authors.lastname: Johansson
authors.forename: T
authors.initials: T
authors.lastname: Lewander
authors.forename: U
authors.initials: U
authors.lastname: Hacksell
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D018360:Crystallography, X-Ray; D004298:Dopamine / Q000096:biosynthesis; D008297:Male; D015394:Molecular Structure; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000502:physiology; D044263:Receptors, Serotonin, 5-HT1; D012701:Serotonin / Q000096:biosynthesis; D012702:Serotonin Antagonists / Q000138:chemical synthesis* / Q000494:pharmacology*; D013237:Stereoisomerism
chemical_list: D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D012702:Serotonin Antagonists; C064282:UH 301; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D004298:Dopamine