Subtype-Selective <i>N</i>-Methyl-<scp>d</scp>-Aspartate Receptor Antagonists: Synthesis and Biological Evaluation of 1-(Heteroarylalkynyl)-4-benzylpiperidines
作者:Jon L. Wright、Tracy F. Gregory、Suzanne R. Kesten、Peter A. Boxer、Kevin A. Serpa、Leonard T. Meltzer、Lawrence D. Wise、Stephen A. Espitia、Christopher S. Konkoy、Edward R. Whittemore、Richard M. Woodward
DOI:10.1021/jm000023o
日期:2000.9.1
4-[4-(4-Benzylpiperidin-1-yl)but-1-ynyl]phenol (8) and 4-[3-(4-benzylpiperidin-1-yl)prop-1-ynyl phenol (9) are potent NR1A/2B receptor antagonists (IC50 values 0.17 and 0.10 mu M, respectively). Administered intraperitoneally, they both potentiated the activity of L-DOPA in the unilaterally 6-hydroxydopamine-lesioned (6-OHDA) rat, a model of Parkinson's disease. However, compound 9 was not active orally, likely due to rapid first-pass metabolism of the phenol moiety. The phenol was replaced by several bicyclic heterocyclic systems containing an NH group to function as a H-bond donor in the hope that these would be less likely to undergo rapid metabolism. In general, indoles, indazoles, benzotriazoles, indolones, and isatins gave analogues with weaker NR1A/2B activity than the parent phenols, while benzimidazolones and benzimidazolinones gave equipotent or more potent analogues. The preference for a para arrangement between the H-bond donor and the linking acetylene moiety was confirmed, and a propyne link was preferred over a butyne link. Substitution on the benzyl group or a 4-hydroxyl group on the piperidine had little effect on NR1A/2B potency; however, 4-hydroxypiperidines demonstrated slightly improved selectivity for NR1A/2B receptors versus alpha-1 adrenergic and dopamine D2 receptor affinity. From this study, 5-[3-(4-benzylpiperidin-1-yl)prop-1-ynyl]-1,3-dihydrobenzo-imidazol-2-one (46b) was identified as a very potent, selective NR1A/2B receptor antagonist (IC50 value 0.0053 mu M). After oral administration at 10 and 30 mg/kg, 46b potentiated the effects of L-DOPA in the 6-OHDA-lesioned rat and seemed to have improved oral bioavailability but lower brain penetration compared to phenol 9.