O'Brien P M, Sliskovic D R, Picard J A, Lee H T, Purchase C F, Roth B D, White A D, Anderson M, Mueller S B, Bocan T, Bousley R, Hamelehle K L, Homan R, Lee P, Krause B R, Reindel J F, Stanfield R L, Turluck D
Department of Chemistry,Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Company, Ann Arbor, Michigan 48105, USA.
J Med Chem. 1996 Jun 7;39(12):2354-66. doi: 10.1021/jm960170f.
A series of tetrazole amide derivatives of (+/-)-2-dodecyl-alpha-phenyl-N-(2,4,6-trimethoxyphenyl)-2H-tetrazole-5- acetamide (1) was prepared and evaluated for their ability to inhibit acyl-CoA: cholesterol O-acyltransferase (ACAT) in vitro and to lower plasma total cholesterol in vivo. For this series of compounds, our objective was to systematically replace substituents appended to the amide and tetrazole moieties of 1 with structurally diverse functionalities and assess the effect that these changes have on biological activity. The ensuing structure-activity relationship (SAR) studies identified aryl (7b) and heteroaryl (7f,g) replacements for 2,4,6-trimethoxyphenyl that potently inhibit liver microsomal and macrophage ACAT in vitro and exhibit good cholesterol lowering activity (56-66% decreases in plasma total cholesterol at 30 mg/kg), relative to 1, when compared in the acute rat model of hypercholesterolemia. Replacement of the alpha-phenyl moiety with electron-withdrawing substituents (13e-h), however, significantly reduced liver microsomal ACAT inhibitory activity (IC50 > 1 microM). This is in contrast to electron-donating substituents (13ij,m-q), which produce IC50 values ranging from 5 to 75 nM in the hepatic microsomal assay. For selected tetrazole amides (1, 7b, 13n,o), reversing the order of substituents appended to the 2- and 5-positions in the tetrazole ring (36a-d), in general, improved macrophage ACAT inhibitory activity and provided excellent cholesterol-lowering activity (ranging from 65% to 77% decreases in plasma total cholesterol at 30 mg/kg) in the acute rat screen. The most potent isomeric pair in this set of unsubstituted methylene derivatives (13n and 36a) caused adrenocortical cell degeneration in guinea pigs treated with these inhibitors. In contrast, adrenal glands taken from guinea pigs treated with the corresponding alpha-phenyl-substituted analogs (7b and 36c) were essentially unchanged compared to untreated controls. Subsequent evaluation of 7b and 36c in a rabbit bioassay showed that both compounds and/or their metabolities were present in plasma after oral dosing. Unlike 7b and 36c, compound 1 and related 2,4,6-trimethoxyanilides (13j, 30c,d) showed poor oral activity in the rabbit bioassay. Nevertheless, in cholesterol-fed rabbits, both systemically available (7b, 36c) and poorly absorbed inhibitors (1, 36d) were more effective in lowering plasma total cholesterol than the fatty acid amide CI-976.
制备了一系列（±）-2-十二烷基-α-苯基-N-（2,4,6-三甲氧基苯基）-2H-四唑-5-乙酰胺（1）的四唑酰胺衍生物，并评估了它们在体外抑制酰基辅酶A：胆固醇O-酰基转移酶（ACAT）以及在体内降低血浆总胆固醇的能力。对于这一系列化合物，我们的目标是用结构多样的官能团系统地取代连接在1的酰胺和四唑部分上的取代基，并评估这些变化对生物活性的影响。随后的构效关系（SAR）研究确定，用芳基（7b）和杂芳基（7f，g）取代2,4,6-三甲氧基苯基，在体外能有效抑制肝微粒体和巨噬细胞ACAT，并且在高胆固醇血症急性大鼠模型中与1相比，表现出良好的降胆固醇活性（30mg/kg时血浆总胆固醇降低56 - 66%）。然而，用吸电子取代基（13e - h）取代α-苯基部分，显著降低了肝微粒体ACAT抑制活性（IC50 > 1μM）。这与给电子取代基（13i，j，m - q）形成对比，在肝微粒体测定中，给电子取代基产生的IC50值范围为5至75 nM。对于选定的四唑酰胺（1、7b、13n、o），一般来说，颠倒连接在四唑环2位和5位上的取代基顺序（36a - d），可提高巨噬细胞ACAT抑制活性，并在急性大鼠筛选中提供优异的降胆固醇活性（30mg/kg时血浆总胆固醇降低65%至77%）。在这组未取代的亚甲基衍生物中，最有效的异构体对（13n和36a）在用这些抑制剂处理的豚鼠中导致肾上腺皮质细胞变性。相比之下，与未处理的对照相比，用相应的α-苯基取代类似物（7b和36c）处理的豚鼠的肾上腺基本未发生变化。随后在兔生物测定中对7b和36c进行评估，结果表明口服给药后血浆中存在这两种化合物和/或它们的代谢物。与7b和36c不同，化合物1和相关的2,4,6-三甲氧基苯胺（13j、30c、d）在兔生物测定中表现出较差的口服活性。然而，在喂食胆固醇的兔子中，全身可利用的抑制剂（7b、36c）和吸收不良的抑制剂（1、36d）在降低血浆总胆固醇方面比脂肪酸酰胺CI - 976更有效。
