Synthesis and Pharmacological Evaluation of 5-(4-Biphenyl)-3-methyl-4-phenyl-1,2,4-triazole Derivatives as a Novel Class of Selective Antagonists for the Human Vasopressin V<sub>1A</sub> Receptor
作者:Akio Kakefuda、Takeshi Suzuki、Takahiko Tobe、Junko Tsukada、Atsuo Tahara、Shuichi Sakamoto、Shin-ichi Tsukamoto
DOI:10.1021/jm010544r
日期:2002.6.1
A series of 5-(4-biphenyl)-3-methyl-4-phenyl-1,2,4-triazole derivatives were prepared and evaluated as selective antagonists for the human vasopressin VIA receptor. The compounds were examined for their affinity to the cloned human VIA receptor (hV(1A)) and selectivity vs the cloned human V-2 receptor (hV(2)). By utilizing the structure-activity relationship on 4,4-difluoro-5-methylidene-2,3,4,5-tetrahydrobenzazepine derivatives as dual antagonists for the VIA and V2 receptors in our previous study, we found that substituting the methoxy group at the 2-position of the 4-phenyl ring with (4-methylpiperazin-1-yl)alkoxy moieties brought about marked improvement of both affinity to hV1A and selectivity vs hV2. Further introduction of a methyl group into the 6-position of the 4-phenyl ring resulted in additional improvement of selectivity. One particular compound, 5-(4-biphenyl)-3-methyl-4-2-[6-(4-methyl-1-piperazinyl)-hexyloxy]phenyl}-1,2,4-triazole (19) showed potent affinity to hV(1A) with a K-i value of 1.04 nM and high selectivity with a 1700-fold selectivity vs hV(2). We also found marked differences in the affinity of compounds in this series between the human and the rat receptors. Compound 19 was further examined for its VIA receptor antagonist activity in rats. As a result, 19 demonstrated antagonist activities toward an arginine vasopressin-induced increase in diastolic blood pressure after intravenous or oral administration and long-lasting oral activity.