ISSN:
0899-0042
Keywords:
optical column
;
HPLC
;
diastereoisomer
;
125I
;
radioligands
;
8-OH-DPAT
;
serotonin receptor
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
(R,S)-trans-8-Hydroxy-2-[N-n-propyl-N-(3′-iodo-2′-propenyl)amino]tetralin 7, a new radioiodinated ligand based on 8-OH-DPAT, was reported as a potential ligand for 5-HT1A receptors. The optically active (+)-(R)- and (-)-(S)-7 were prepared to investigate the stereoselectivity of (R,S)-7. Racemic intermediate 8-methoxy-2-N-n-propyltetralin was reacted with the acyl chloride of (-)-(R)-O-methylmandelic acid to form a mixture of (S,R)- and (R,R)-diastereoisomers, which were separated by flash column chromatography. After removing the N-acyl group from the diastereoisomers, the desired (+)-(R)-or (-)-(S)-7 was obtained by adding an N-iodopropenyl group. In vitro homogenate binding studies showed the stereoselectivity of this new compound for 5-HT1A receptors. (+)-(R)-7 isomer displayed 100-fold higher affinity than the (-)-(S)-7 isomer. Biochemical study indicated that (+)-(R)-7 potently inhibited forskolin-stimulated adenylyl cyclase activity in hippocampal membranes (Emax and EC50 were 24.5% and 5.4 nM, respectively), while (-)-(S)-7 showed no effect at 1 μM. The radioiodinated (+)-(R)- and (-)-(S)-[125I]7 were confirmed by coelution with the resolved unlabeled compound on HPLC (reverse phase column PRP-1, acetonitrile/pH 7.0 buffer, 80/20). The active isomer, (+)-(R)-[125I]7, displayed high binding affinity to 5-HT1A receptors (Kd = 0.09 ± 0.02 nM). In contrast, the (-)-(S)-7 isomer displayed a significantly lower affinity to the 5-HT1A receptor (Kd 〉 10 nM). Thus, (+)-(R)-[125I]trans-8-OH-PIPAT, (+)-(R)-7, an iodinated stereoselective 5-HT1A receptor agonist, is potentially useful for study of in vivo and in vitro function and pharmacology of 5-HT1A receptors in the central nervous system. © 1995 Wiley-Liss, Inc.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chir.530070611
Permalink
