Synthesis of Novel GABA Uptake Inhibitors. 3. Diaryloxime and Diarylvinyl Ether Derivatives of Nipecotic Acid and Guvacine as Anticonvulsant Agents
作者:Lars J. S. Knutsen、Knud Erik Andersen、Jesper Lau、Behrend F. Lundt、Rodger F. Henry、Howard E. Morton、Lars Nærum、Hans Petersen、Henrik Stephensen、Peter D. Suzdak、Michael D. B. Swedberg、Christian Thomsen、Per O. Sørensen
DOI:10.1021/jm981027k
日期:1999.9.1
(3R)-1-[4,4-bis(3-methyl-2-thienyl)-3-buteny] acid 1(tiagabine, Gabitril) is a potent and selective gamma-aminobutyric acid (GABA) uptake inhibitor with proven anticonvulsant efficacy in humans. This drug, which has a unique mechanism of action among marketed anticonvulsant agents, has been launched for add-on treatment of partial seizures with or without secondary generalization in patients > 12 years of age. Using this new agent as a benchmark, we have designed two series of novel GABA uptake inhibitors of remarkable potency, using a putative new model of ligand interaction at the GABA transporter type 1 (GAT-1) uptake site. This model involves the postulated interaction of an electronegative region in the CABA uptake inhibitor with a positively charged domain in the protein structure of the GAT-1 site. These two novel series of anticonvulsant agents contain diaryloxime or diarylvinyl ether functionalities linked to cyclic amino acid moieties and were derived utilizing the new model, via a series of design steps from the known 4,4-diarylbutenyl GABA uptake inhibitors. The new compounds are potent inhibitors of [H-3]-GABA uptake in rat brain synaptosomes in vitro, and their antiepileptic potential was demonstrated in vivo by their ability to protect against seizures induced by the benzodiazepine receptor inverse agonist methyl 4-ethyl-6,7-dimethoxy-beta-carboline-3-carboxylate (DMCM) in mice. From structure-activity studies of these new GABA uptake inhibitors, we have shown that insertion of an ether oxygen in conjugation with the double bond in tiagabine (K-i = 67 nM) improves in vitro potency by 5-fold to 14 nM.
(3R)-1-[4,4-双(3-甲基-2-噻吩基)-3-丁炔基]乙酸(丙戊酸钠,商品名:Gabitril)是一种强效且选择性的γ-氨基丁酸(GABA)摄取抑制剂,在人类中已被证实具有抗惊厥效果。这种药物在已上市的抗惊厥药物中具有独特的作用机制,目前已被批准用于12岁以上患者的部分性癫痫发作的辅助治疗,无论是否伴有继发性全面性发作。
以此新型药物作为参考,我们设计了两个系列的新型GABA摄取抑制剂,这些抑制剂展现出显著的 potency。我们采用了GABA转运蛋白类型1(GAT-1)摄取位点上的一种新型配体相互作用模型。该模型假设GABA摄取抑制剂中的一个带负电的区域与GAT-1位点蛋白质结构中的一个带正电的区域发生相互作用。
这两个系列的新型抗癫痫药物包含 diaryloxime 或 diarylvinyl醚功能基团,并与环状氨基酸部分相连。它们是从已知的4,4-二芳基-1-丁烯基GABA摄取抑制剂出发,利用新模型并通过一系列设计步骤衍生而来的。
实验表明,这些新化合物在体外对大鼠脑突触体中的[H-3]-GABA摄取表现出强效抑制作用,且在体内通过保护小鼠免受苯二氮卓受体反向激动剂——甲基4-乙基-6,7-二甲氧基-β-咔啉-3-羧酸酯(DMCM)引起的癫痫发作,进一步证明了它们的抗癫痫潜力。
通过这些新型GABA摄取抑制剂的构效关系研究,我们发现:在丙戊酸钠的骨架中引入与双键共轭的醚氧键(Ki = 67 nM)可使体外活性提高5倍,达到14 nM的效力。