Inhibitors of Phenylethanolamine <i>N</i>-Methyltransferase That Are Predicted To Penetrate the Blood−Brain Barrier: Design, Synthesis, and Evaluation of 3-Fluoromethyl-7-(<i>N</i>-substituted aminosulfonyl)-1,2,3,4-tetrahydroisoquinolines That Possess Low Affinity toward the α<sub>2</sub>-Adrenoceptor
作者:F. Anthony Romero、Steven M. Vodonick、Kevin R. Criscione、Michael J. McLeish、Gary L. Grunewald
DOI:10.1021/jm0400653
日期:2004.8.1
(+/-)-7-Aminosulfonyl-3-fluoromethyl-1,2,3,4-tetrahydroisoquinoline (7) is one of the most potent and selective inhibitors of phenylethanolamine N-methyltransferase (PNMT) reported to date, but a blood-brain barrier (BBB) model indicates that it cannot penetrate the BBB. To increase the lipophilicity of 7 by addition of a nonpolar substituent to the sulfonamide nitrogen, a small library of (+/-)-3-fluoromethyl-7-(N-substitutedaminosulfonyl)-1,2,3,4-tetrahydroisoquinolines was synthesized and evaluated as inhibitors of PNMT and for affinity at the alpha(2)-adrenoceptor. In addition, this library probed the PNMT active site surrounding the sulfonamide nitrogen of 7. Bulky substituents on the sulfonamide nitrogen are disfavored at the PNMT active site more so than at the a2-adrenoceptor (thus reducing selectivity). On the other hand, alkyl chains on the sulfonamide nitrogen that contain an electron dense atom, such as a fluorine, are favored in the PNMT active site and possess little a2-adrenoceptor affinity, thereby conferring good selectivity (>500). Several members of the library (8, 14, 17, and 18) have excellent PNMT inhibitory potency and selectivity and are predicted, on the basis of their ClogP value (> 0.5), to penetrate the BBB to a significant extent. Compounds 17 and 18 are the most potent and selective PNMT inhibitors reported to date.
(+/-)-7-氨基磺酰基-3-氟甲基四氢异喹啉(7)是迄今为止报道的最有效和选择性最强的苯乙醇胺N-甲基转移酶(PNMT)抑制剂之一,但基于血脑屏障(BBB)模型的测试表明,它无法穿透BBB。为了通过在磺酰胺氮上添加非极性取代基来提高7的脂溶性,合成并评估了一系列(+/-)-3-氟甲基-7-(N-取代氨基磺酰基)四氢异喹啉,作为PNMT的抑制剂以及在α(2)-肾上腺素受体上的亲和力。此外,该库通过在7的磺酰胺氮周围的区域对PNMT的活性位点进行了研究。发现较大的取代基在PNMT活性位点的不受欢迎程度远高于α2-肾上腺素受体(从而降低选择性)。
另一方面,磺酰胺氮上的含电子丰富的原子(如氟)的烷基链在PNMT活性位点受到青睐,并且对α2-肾上腺素受体的亲和力极低,因而具有良好的选择性(>500)。该库中的多种化合物(8、14、17和18)展现了出色的PNMT抑制活性和选择性,并且基于它们的ClogP值(>0.5),预计这些化合物可以显著穿透BBB。化合物17和18是目前为止报告的最有效的选择性PNMT抑制剂。