Novel 1-hydroxyazole bioisosteres of glutamic acid. Synthesis, protolytic properties, and pharmacology.
Novel 1-hydroxyazole bioisosteres of glutamic acid. Synthesis, protolytic properties, and pharmacology.
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谷氨酸的新型 1-羟唑生物等排体。
DOI：
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发表时间：
2002
影响因子：
7.3
通讯作者：
P. Vedsø
中科院分区：
文献类型：
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作者：
T. Stensbøl;P. Uhlmann;S. Morel;B. L. Eriksen;J. Felding;H. Kromann;M. B. Hermit;J. Greenwood;H. Braüner;U. Madsen;F. Junager;P. Krogsgaard‐Larsen;M. Begtrup;P. Vedsø
合成了许多 1-羟唑衍生物，作为 (S)-谷氨酸 (Glu) 的生物等排体和 AMPA 受体激动剂 (R,S)-2-氨基-3-(3-羟基-5-甲基-4-异恶唑基)丙酸 (AMPA, 3b) 的类似物。所有化合物均经过体外药理学研究，包括一系列 Glu 受体结合测定、天然和克隆 Glu 摄取系统的摄取研究以及电生理大鼠皮质切片模型。化合物 7a、b 是带有 1-羟基-5-吡唑基部分作为远端羧基官能团的 AMPA 类似物，对 [3H]AMPA 受体结合位点仅表现出中等亲和力（分别为 IC(50) = 2.7 +/- 0.4 microM 和 IC(50) = 2.6 +/- 0.6 microM），与大鼠皮质楔形模型的电生理学数据相关（EC(50) =分别为 280 +/- 48 microM 和 EC(50) = 586 +/- 41 microM）。 AMPA 的 1-Hydroxy-1,2,3-triazol-5-yl 类似物（化合物 8a,b）对 [3H]AMPA 受体结合位点表现出高亲和力（分别为 IC(50) = 0.15 +/- 0.03 microM 和 IC(50) = 0.13 +/- 0.02 microM）。电生理学数据显示，化合物 8a 在大鼠皮质楔形模型中缺乏活性 (EC(50) > 1000 microM)，而相应的 4-甲基类似物 8b 是一种有效的 AMPA 受体激动剂 (EC(50) = 15 +/- 2 microM)。根据这种差异，发现化合物 8a 抑制突触体 [3H]D-天冬氨酸摄取 (IC(50) = 93 +/- 25 microM)，以及兴奋性氨基酸转运蛋白 (EAAT) EAAT1 (IC(50) = 100 +/- 30 microM) 和 EAAT2 (IC(50) = 300 +/- 80 microM)。相比之下，化合物 8b 对 Glu 摄取位点没有明显的亲和力，既不是突触体也不是克隆的。具有 1-羟基咪唑作为末端酸性官能团的化合物 9a-c 和 10a,b 在所有测试的系统中均缺乏活性。通过滴定测定化合物 7a、b、8b 和 9b 的质子分解性质，pK(a) 值与 AMPA 受体活性之间的相关性很明显。所有合成配体的优化结构均符合 AMPA-GluR2 构建体的已知晶体结构。当观察到 AMPA 受体的亲和力显着降低或消除时，可以根据配体与构建体的配合能力来合理化这一点。本文提出的结果指出了 1-羟基吡唑和 1,2,3-羟基三唑作为 Glu 受体和转运蛋白的羧酸生物等排体的用途。这些化合物均未表现出对代谢型 Glu 受体的显着活性。
A number of 1-hydroxyazole derivatives were synthesized as bioisosteres of (S)-glutamic acid (Glu) and as analogues of the AMPA receptor agonist (R,S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA, 3b). All compounds were subjected to in vitro pharmacological studies, including a series of Glu receptor binding assays, uptake studies on native as well as cloned Glu uptake systems, and the electrophysiological rat cortical slice model. Compounds 7a,b, analogues of AMPA bearing a 1-hydroxy-5-pyrazolyl moiety as the distal carboxylic functionality, showed only moderate affinity for [3H]AMPA receptor binding sites (IC(50) = 2.7 +/- 0.4 microM and IC(50) = 2.6 +/- 0.6 microM, respectively), correlating with electrophysiological data from the rat cortical wedge model (EC(50) = 280 +/- 48 microM and EC(50) = 586 +/- 41 microM, respectively). 1-Hydroxy-1,2,3-triazol-5-yl analogues of AMPA, compounds 8a,b, showed high affinity for [3H]AMPA receptor binding sites (IC(50) = 0.15 +/- 0.03 microM and IC(50) = 0.13 +/- 0.02 microM, respectively). Electrophysiological data showed that compound 8a was devoid of activity in the rat cortical wedge model (EC(50) > 1000 microM), whereas the corresponding 4-methyl analogue 8b was a potent AMPA receptor agonist (EC(50) = 15 +/- 2 microM). In accordance with this disparity, compound 8a was found to inhibit synaptosomal [3H]D-aspartic acid uptake (IC(50) = 93 +/- 25 microM), as well as excitatory amino acid transporters (EAATs) EAAT1 (IC(50) = 100 +/- 30 microM) and EAAT2 (IC(50) = 300 +/- 80 microM). By contrast, compound 8b showed no appreciable affinity for Glu uptake sites, neither synaptosomal nor cloned. Compounds 9a-c and 10a,b, possessing 1-hydroxyimidazole as the terminal acidic function, were devoid of activity in all of the systems tested. Protolytic properties of compounds 7a,b, 8b, and 9b were determined by titration, and a correlation between the pK(a) values and the activity at AMPA receptors was apparent. Optimized structures of all the synthesized ligands were fitted to the known crystal structure of an AMPA-GluR2 construct. Where substantial reduction or abolition of affinity at AMPA receptors was observed, this could be rationalized on the basis of the ability of the ligand to fit the construct. The results presented in this article point to the utility of 1-hydroxypyrazole and 1,2,3-hydroxytriazole as bioisosteres of carboxylic acids at Glu receptors and transporters. None of the compounds showed significant activity at metabotropic Glu receptors.