【作者】 汪燕翔；

【导师】 蒋建东； 宋丹青；

【作者基本信息】 中国协和医科大学 ， 微生物与生化药学， 2010， 博士

【摘要】 我研究所首次发现,我国天然产物——小檗碱(BBR,结构式见图1)是一个作用机制与他汀类药物完全不同的新型降血脂药物,主要在转录后水平经ERK信号转导通路,上调肝细胞低密度脂蛋白受体(LDLR)的基因表达,进而发挥其降脂活性。近年来,我研究所还发现,BBR可以通过PKC通路激活InsR启动子增加InsR mRNA的转录,上调胰岛素受体(InsR)水平,进而发挥降血糖作用。另外,文献报道BBR显示降血糖作用是通过AMPK的磷酸化,激活AMPK通路。提示BBR具有治疗代谢综合征(MS)的潜力。本论文在前期工作基础上,以BBR为先导物,针对其A和D环取代侧链,通过全合成手段,继续开展结构修饰与优化,共合成了15个新BBR类似物。并通过对上调LDLR、InsR表达以及激活AMPK活性的评价,补充与完善此类衍生物上调LDLR、InsR表达,和激活AMPK活性的构效关系,并勾画出相应的构效关系总图。为了进一步探索BBR多种药效作用的体内化学机制,本论文还合成了BBR的4个体内代谢产物M1-M4。活性研究结果表明：M1有较好的上调LDLR、InsR以及激活AMPK活性,却低于母体化合物BBR。但9-位中裸露出的羟基使通过制备前药提高BBR口服生物利用度成为可能,有望获得具有自主知识产权、良好药代动力学特性的治疗MS的候选物。在BBR类似物的全合成过程中,我们意外发现了另外一类产物——N-(2-芳乙基)异喹啉类衍生物的生成。鉴于此类化合物的现有合成方法有限,结构种类不能多样化,活性尚未见文献报道,本论文深入探讨并阐述了这两类衍生物形成的化学反应机理,使所需要的目标化合物能够定向设计与合成。由此,我们发明了一种N-(2-芳乙基)异喹啉类衍生物的全新合成方法：即以乙二醛作为“二碳单位”,当A环3-位不存在活化基团(如甲氧基等),D环10-位有给电子取代基(如羟基等)时,即可生成N-(2-芳乙基)异喹啉类衍生物。与经典的的异喹啉合成方法相比,此方法操作简便,收率高,补充与完善了经典的异喹啉合成方法,丰富了此类化合物的结构类型。总结了两类衍生物形成的化学机理：BBR类似物和N-(2-芳乙基)异喹啉类衍生物的C环形成均基于Friedel-Craft烷基化反应；而BBR类似物B环的形成则遵循Pictet-Spengler环化反应规则。据此,设计合成了63个N-(2-芳乙基)异喹啉衍生物验证了此反应机理的正确性。针对所合成的N-(2-芳乙基)异喹啉衍生物进行了活性筛选,发现其具有较好的抑制清道夫受体CD36活性。初步构效关系分析表明：A环上的活化基团有利于活性的提高,钝化基团降低活性,3-位甲氧基取代对提高活性有利。14-位羟基取代活性降低,D环二取代活性高于单取代,10-位的邻对位定位基对活性贡献较大。其中化合物W9、W50、W56显示出较强的CD36拮抗活性,IC50分别为0.18、0.27和0.77 ug/mL。为进一步的研究提供了重要的物质基础。对所合成的N-(2-芳乙基)异喹啉衍生物进行了肠道病毒COX-B3的活性筛选。得到了W18和W21两个候选化合物,其选择性指数(SI)分别为阳性对照药病毒唑(RBV)的4.5倍和2.6倍,推荐进入体内活性研究。本论文共合成了179个化合物,其中目标产物81个,77为未见文献报道的新化合物,其结构经MS、1HNMR及IR等图谱确证无误。部分研究内容在Bioorg. Med. Chem.Lett. (2009)杂志上发表。更多还原

【Abstract】 Berberine (BBR) is a natural compound with up-regulating expression on both low-density-lipoprotein receptor (LDLR) and insulin receptor (InsR), and also exhibiting an ideal activity on activating AMPK. It increases low-density-lipoprotein receptor (LDLR) expression by stabilization of LDLR mRNA. In addition, We have discovered insulin receptor (InsR) to be another key target of BBR. BBR activated the promoter of InsR gene through a protein kinase C (PKC) pathway, increased the expression of InsR in liver and muscle cells, and therefore enhanced glucose consumption. So BBR shows a great potential on treating metabolic syndrome (MS). With BBR as lead,15 analogues were synthesized, the activity of up-regulation on LDLR, InsR mRNA expression and AMPK activating activity were examined. Taken the previous results together, we improved and completed the SAR based on these screening models.To disscuss the mechanism of action for BBR in vivo,4 metabolites (M1-M4) of BBR were synthesized. M1 exhibits an ideal activity on up-regulating LDLR and on activating AMPK. Therefore, the hydroxyl makes it possible to construct pro-drugs at the 9-position.During the process of BBR analogues synthesizing, we discovered another category of isoquinoline, N-(2-arylethyl) isoquinoline occasionally. The way for synthesizing them was limited, and the activity of N-(2-arylethyl) isoquinolines has not been reported. So we elucidate the mechanism of the synthesis for BBR analogues and N-arylethyl isoquinoline derivatives, and synthesize the definite derivative based on the mechanism. A novel and convient method for the synthesis of BBR derivates and N-(2-arylethyl) isoquinoline using glyoxal as the "two-carbon unit" was invented. The formation of ring C follows the orientation principle of the Friedel-Crafts reaction with regard to both kinds. The ring B of BBR analogues forms based upon the principle of the Pictet-Spengler reaction. It is an improvement to the classical methods of isoquinoline synthesis.Different substituents on ring A and D could determine the category of the final product. The ortho-para directing group at the 10-position of ring D is of assistance to the formation of the aromatic ring C. The activating group (alkoxy in this paper) at the 3-position of ring A is essential to form ring B. And then,63 derivatives were synthesized to prove these principles.After screening, SAR analysis of N-(2-arylethyl) isoquinoline derivatives for CD36 antagonists was carried out. The results suggested that introducing suitable activating groups at the ring A might increase inhibition activities for the receptor. Methoxy at the 3-position helps retain the activity, and electron donating groups at the meta position of ring D enhance the activity while electron withdrawing groups reduce it. Meanwhile, when ring D was bis-substituted the activity was much higher. When hydroxyl at the 14-position was introduced, the activity might be weakened. Compounds W9, W50 and W56 showed outstanding activities than the positive control. The IC50 of these three derivatives were 0.18,0.27 and 0.77 respectively which encouraged us to do more researches in-depth afterwards.N-(2-arylethyl) isoquinoline derivatives showed certain activities upon COX-B3 virus. W18 and W21 were screened out with 2.6 and 4.5 folds of the positive control-RBV via the selective index datas. We consider the compound W18 and W21 promising candidates for further investigation in vivo.179 compounds were synthesized, and 81 of them were target compounds. What’s more,77 among them were new compounds. Their structures were confirmed by MS, 1H NMR and IR. Parts of the work were published on BMCL (2009).更多还原