第一部分 新型態有機反應之開發 第二部分 抑制SARS病毒蛋白酶分子設計與合成

Part I. Development of Novel Synthetic Methodology Part II. Design and Synthesis of SARS-CoV 3CL Protease Inhibitors

謝俊結(Jiun-Jie Shie)

指導教授 ： 方俊民

國立臺灣大學/理學院/化學研究所/博士(2005年)

https://doi.org/10.6342/NTU.2005.01433

摘要

本論文主要分成兩大部分：在第一部分內容中，我們將闡述實驗室所開發出新形態有機反應，並應用於一系列特定化合物之合成。其中包含多取代苯并噻吩、噻吩化合物的製備以及醛類官能基轉換之水溶液反應。在第二部分的內容將鎖定於設計與合成新型SARS冠狀病毒蛋白酶抑制劑。
在第一部分的研究，首先討論2-噻吩乙酮與一系列羰基化合物之交叉式偶合反應。探討以二碘化銩、二碘化釤或二碘化釤搭配六甲基磷醯胺等不同試劑對於反應性及其反應型態進行比較討論。
同時我們也利用二碘化銩或二碘化釤/六甲基磷醯胺試劑促使2-噻吩甲酸乙酯及酮類化合物進行二次還原性親電性加成反應，獲得高度立體選擇性之偶合化合物，並且藉由進行脫水反應、聯繼性氧化反應-電子環化反應-氧化反應，便可合成多種不同取代基的苯并噻吩化合物及含噻吩之多環化合物。依相同模式也能應用於合成新型光變色物質---含噻吩之三烯化合物。
在水相有機反應方面，我們則將有機醛類化合物在水溶液中成功進行官能基轉換成氰類(nitriles)、醯胺類 (amides)、吖嗪類 (azines)、三嗪類 (triazines)及四唑類 (tetrazoles)等相對應化合物。並且利用簡單過濾、沉澱與洗滌的實驗操作步驟，便可完成分離純化。
在論文第二部分中，我們著重於以分子結構為基礎下，設計及其合成各類型SARS病毒蛋白酶抑制分子，利用螢光抑制活性測試系統，快速篩選具有抑制效果分子，並且由一系列細胞內測試，證實這些分子對於正常細胞並無毒性條件下，有效抑制SARS病毒複製。我們同時也建立相關抑制分子資料庫，希望在未來運用於一些其他新興病毒的蛋白酶抑制研究上，希望在快速篩選機制下，從中獲得設計修飾抑制分子相關訊息。

關鍵字

二碘化釤 ； 二碘化銩 ； 苯并噻吩 ； 光變色系統

並列摘要

This thesis is composed of two parts: the first part is to develop the novel organic synthetic methodology, such as the preparation of polysubstituted thiophenes, benzothiophenes and transformation of organic aldehydes in aqueous solution. The second part is to design and synthesize the SARS-CoV 3CL protease inhibitors.

Part I. Development of novel synthetic methodology
First, we describe the comparative study of TmI2, SmI2, and SmI2/ HMPA in the cross-coupling reactions of 2-acetylthiophene with carbonyl compounds. The reaction mode of TmI2 is found to be similar to that of SmI2/HMPA, but different from that of SmI2.
By a similar procedure, we have developed a three-step procedure for the preparation of polysubstituted benzothiophenes and the related sulfur-containing polycyclic aromatic compounds. By the promotion of SmI2/HMPA or TmI2, thiophene-2-carboxylate underwent a double- electrophilic reaction effectively with a variety of ketones, followed by acid-catalyzed dehydration and oxidative aromatization, to give a series of sulfur-containing polycyclic aromatic compounds that are not easily prepared by other approaches. This method is also applicable to the preparation of a novel photochromic system of 4,5-dialkenylthiophenes.
In another study, we have explored a new methodology using one-pot tandem reactions for the direct conversion of aldehydes to amides, tetrazoles, and triazines, via addition of H2O2, NaN3/ZnBr2, and dicyandiamide/KOH to the intermediate nitriles. These reactions are conducted smoothly by an initial treatment with iodine in aqueous ammonia, and the desired products are obtained simply by extraction or filtration.

Part II. Design and synthesis of SARS-CoV 3CL protease inhibitors
Severe acute respiratory syndrome (SARS) is an emerging infectious disease caused by a novel variant of coronavirus (SARS-CoV). Currently, no effective drug exists to treat SARS-CoV infection.
In this study, we have explored efficient methods to synthesize nearly 700 compounds, including AG7088 and its analogs. Although the previous reports in the literature have predicted AG7088 may show antiviral activities against SARS 3CL protease, it turns out to be inactive by the cell-based assay. However, by our primary screening using fluorescence assay, we have found a number of potent 3CL protease inhibitors with various core structures, such as conjugated ester, indanol amide, aniline amide, thiazine, C2-symmetric diol and benzotriazole.
On the basis of these results, we thus set the specific aims to discover more potent 3CL protease inhibitors, such as peptidomimetic, unsaturated esters and anilide compounds. The most potent inhibitor 92 is an anilide derived from 2-chloro-4-nitroaniline, L-phenylalanine and 4-(dimethylamino)benzoic acid. This anilide is a competitive inhibitor of the SARS-CoV 3CL protease with Ki = 0.03 μM. Another protease
inhibitor 68o with an inhibition constant of 0.52 μM is obtained by
condensation of the Phe-Phe dipeptide α,β-unsaturated ester with
4-(dimethylamino)cinnamic acid. The cell-based assays also indicate that
68o is a nontoxic anti-SARS agent with an EC50 value of 0.18 μM.

並列關鍵字

SmI2 ； TmI2 ； benzothiophene ； photochromic system ； SARS

參考文獻

3. Klemm, Z. Anorg. Chem. 1929, 184, 352.

8. Thompson L. C. In Handbook on the Physics and Chemistry of Rate Earths; Gschneidner, K. A. Jr.; Eyring L. Eds.; North-Holland Publishing Company: Amsterdam, 1979; Chap. 25.

10. Evans, W. J. Polyhedron 1987, 6, 803.

第一部分參考資料:

1. (a) Wöhler, F. Ann. Phys. Chem. 1828, 12, 253. (b) Kolbe, H. Ann. Chem. Pharm. 1845, 54, 145. (c) Fisher, E. Ber. Dtsc. Chem. Ges. 1890, 23, 799. (d) Perkin, W. H. J. Chem. Soc. 1904, 654. (e) Robinson, R. J. Chem. Soc. 1917, 762. (f) Fisher, H.; Zeile, K. ibid. 1929, 468, 98. (g) Bachmann, W. E.; Cole, W.; Wilds, A. L. J. Am. Chem. Soc. 1939, 61, 974. (h) Woodward, R. B.; Doering, W. E. J. Am. Chem. Soc. 1944, 66, 849. (i) Woodward, R. B. ibid. 1973, 33, 145. (j) Corey, E. J.; Kang, M.-C.; Desai, M. C.; Ghosh, A. K.; Houpis, I. N. J. Am. Chem. Soc. 1988, 110, 649.