Novel Histamine H3 Receptor Antagonists: Synthesis and Evaluation of Formamidine and S-Methylisothiourea Derivatives.
作者:Tomokazu GOTO、Hiroshi SAKASHITA、Kazuki MUARKAMI、Masanori SUGIURA、Takao KONDO、Chikara FUKAYA
DOI:10.1248/cpb.45.305
日期:——
In order to obtain a new, potent and selective histamine H3 receptor antagonist, chemical modifications of thioperamide, a well-known H3 receptor antagonist, were conducted. A new series of compounds has een synthesized by modifying the thiourea and cyclohexyl groups of thioperamide, and tested for H3 receptor affinity by receptor binding assay using plasma membrane from rat cerebral cortex. The thiourea group of thioperamide was found to be replaceable with a basic moiety such as formamidine or S-methylisothiourea. Replacement of the cyclohexyl group in thioperamide by a 1-adamantyl or an exo-2-norbornyl group increased the affinity for H3 receptor. Among the compounds synthesized, N-(1-adamantyl)-N', N'-[3-(4(5)-1H-imidazolyl)pentamethylene]formamidine 3f (AQ0145) showed the highest H3 receptor affinity, having a potent antagonistic activity. This compound was at least 1000-fold more active towards H3 than towards H1 and H2 receptors.
为了获得一种新型、强效、选择性的组胺H3受体拮抗剂,对众所周知的H3受体拮抗剂硫哌丁胺进行了化学修饰。通过修饰硫过酰胺的硫脲和环己基合成了一系列新的化合物,并使用大鼠大脑皮层质膜通过受体结合测定法测试了 H3 受体亲和力。发现硫过酰胺的硫脲基团可以被碱性部分例如甲脒或S-甲基异硫脲取代。用 1-金刚烷基或外型-2-降冰片基取代硫过酰胺中的环己基可增加对 H3 受体的亲和力。在合成的化合物中,N-(1-金刚烷基)-N',N'-[3-(4(5)-1H-咪唑基)五亚甲基]甲脒3f (AQ0145)表现出最高的H3受体亲和力,具有强效拮抗作用。活动。该化合物对 H3 受体的活性比对 H1 和 H2 受体的活性至少高 1000 倍。