新藥研發及藥物合成與新合成方法的開發及其研究

Abstract

本論文內容主要包含三個部分：

第一部分─小分子藥物研發及先導藥物最佳化： (1) 抗癌標靶藥物研發。 (2) 免疫抑制藥物研發。

(1) 抗癌標靶藥物研發 首先我們以VEGFR3小分子抑制劑為標的。主要內容為本實驗室之生技製藥國家型計畫，主要是設計與合成類藥性（Druglikeness）分子庫，經台大毒理所郭明良教授之高通量篩選產生出先導藥物，並由台大資工所曾宇鳳教授進行電腦模擬中找出可能的作用機制及結構最佳化的模擬，藉此運作方式產生不同代數的候選藥物。經由VEGFR3抑制活性篩選平台，我們發現了許多具有抑制VEGFR3活性的化合物。首先我們延續先導藥物＃1250、 ＃194的實驗，持續修飾化合物結構以及利用適當配方技術增加溶解度以及提高藥物功能。而後我們在＃194衍生物＃253的生物活性上得到突破性的結果。＃253之抑制效力與上市藥物舒癌特（Sutent）不相上下，＃253類的衍生物尤其是在溶解度以及對tumor size的影響都有顯著的提昇，且在副作用方面甚至比上市藥物索拉非尼（Sorafenib）更少，包含在皮膚以及體重等表徵上。此外＃253在不同的癌細胞都有顯著的抑制效果，此化合物目前已進入臨床前之抗癌動物實驗，以口服方式給予藥劑，測試結果發現#253可以有效的抑制癌細胞的內皮組織增生，進而抑制癌症細胞的生長，目前已經發表專利並技術轉移至財團法人生物技術開發中心（Development Center for Biotechnology, DCB）。

(2) 免疫抑制藥物研發 在免疫抑制藥物研發上，我們與國家實驗研究院奈米元件實驗室陳惠民博士合作，2006年陳惠民博士發表了經由蛋白質晶片快速篩選找出免疫抑制藥物洋薊酸（Cynarin），遺憾的是洋薊酸對T細胞具有細胞毒性。我們以洋薊酸為基礎進行設計並合成出一系列天然物衍生物由活性測試結果中發現，我們的先導藥物與洋薊酸相比有著較佳的免疫抑制效果，並且細胞毒性非常低。在動物體內測試進一步證實，我們的先導藥物可以減少小鼠的過敏性反應。基於這些觀察，我們的先導藥物在未來的免疫抑製藥物開發中可以進一步發展作為免疫抑製的候選藥物。

第二部分─有機合成之方法開發及其反應機制探討： (1) 超音波輔助多組成一鍋化反應。 (2) 多組成一鍋化碳氫鍵活化反應。

(1) 超音波輔助多組成一鍋化反應 在超音波輔助多組成一鍋化反應方面，主要是以芳香醛、1,3-環己二酮和2-氨基苯並咪唑在異丙醇和水中經由超音波輔助進行三組分一鍋化反應合成了一系列新型苯並咪唑並[2,1-b]喹啉-6-酮衍生物。該方法具有反應條件溫和、反應時間短、產率高及環境無害等優點。反應經X光單晶繞射確證了結構，並經由氣相層析質譜儀以及中間產物之X光單晶繞射結構推論一新的反應機制。

(2) 多組成一鍋化碳氫鍵活化反應 在多組成一鍋化碳氫鍵活化反應方面，我們發現了一個創新的合成方法，可經由鄰胺基苯酚或鄰胺基苯硫酚與碘苯反應生成苯並噁唑和苯並噻唑。在這種方法中的關鍵步驟涉及的鄰-胺基與N, N'-二甲基甲酰胺的酰胺基轉換反應接著以C-H鍵活化的方式進行耦合然後進行環化脫水的反應。這個方法可以快速且大量的合成出許多具分子多樣性的苯並噁唑或苯並噻唑。並且我們由中間產物之鑑定推導出此一反應之反應機制。

第三部分─市售藥物西羅多辛之合成及合成方法開發 在臨床核可販售用於治療良性前列腺增生的藥物西羅多辛（Silodosin）的合成及合成方法開發上，我們主要將市售化合物118與化合物119結合之化合物120與(S)-(+)-扁桃酸（mandelic acid）經由超音波輔助進行不對稱拆分 （Chiral resolution），此外我們以步驟較少的合成策略去進行後續合成，有效提升了西洛多辛的總產率。

ABSTRACT There are three parts in this thesis.

Part 1: Small molecule drug discovery and hit discovery and lead optimization, include the (1) Anti-cancer target-drug discovery. (2) Immuno-suppressive drug discovery.

(1) Anti-cancer target-drug discovery We focus design and synthesized on VEGF inhibitor. Our team includes the cancer molecular biology team lead by Prof. Min-Liang Kuo, synthetic chemistry team by Prof. Chung-Ming Sun, and molecular modeling team lead by Prof. Yu-feng Tseng. Our principal goal of this integrated project is to identify, synthesize, and optimize VEGF inhibitors with good safety and pharmacokinetics profiles ready for clinical testing in cancer treatment. By using VEGFR3 activity screening platform, we found many compounds with high activity on inhibiting VEGFR3. Based on the results of previous efforts, the candidate was changed from #1250 to #194 as the later has more inhibition ability toward VEGFR-3. Further we have an important breakthrough in #253, the derivatives of #194. The obtained results were shown remarkable promotion in the solubility and the inhibition ability. One of the compounds in #253 shows remarkable inhibition ability as equal as to Sutent. It has even less side effects than the listed drug sorafenib, including the characterization of the skin and weight. It also exhibit significant inhibitory effect in different cancer cells. Preclinical studies in animals model had been carried out, was given orally. Then, that result showed the efficacy on suppressing tumor growth, and dramatically attenuated the growth of VEGFR3-overexpressed tumors in vivo. In addition, paten has published and experience of technical shift to Development Center for Biotechnology (DCB).

(2) Immuno-suppressive drug discovery Our partner is Dr. Chen Hueih-Min at National Nano Device Laboratories. An immuno-suppressive compound─cynarin, he found by an efficient drug screening method publish on 2006. Unfortunately, cynarin has toxicity on T-cells is surprising. Accordingly, a lead compound was created and synthesized from cynarin simulate. The results showed that in vitro used our lead compound has very low toxicity on T-cells and higher effect on immuno-responses of T-cell as compared with cynarin. In vivo animal tests further confirmed our lead compound can reduce the allergic responses of mice. Based on these observations, our lead compound can be further developed as a candidate of immuno-suppressive agent in the future.

Part 2: Development of the Synthetic Method and Study of Formation Mechanism, include the (1) Ultrasound-assisted one-pot multicomponent reaction. (2) one-pot multicomponent C-H activation reaction.

(1) Ultrasound-assisted one-pot multicomponent reaction The benzimidazo[2,1-b]quinazolin-6-one directives has been synthesized via ultrasound-assisted three-component reaction of benzoimidazol-2-amine with benzaldehyde and 1,3-cyclodione in isopropanol, and its structure was determined by monocrystalline X-ray diffraction. The mechanism of reaction and reaction rate has been studied with GC-Mass and intermediate X-ray structure.

(2) one-pot multicomponent C-H activation reaction An innovative one-pot Pd-catalyzed transamidation C-H activation and cyclodehydration strategy for the synthesis of substituted benzoxazoles and benzothiazoles from o-aminophenols or o-aminothiophenols has been developed. The key step involves in this approach an transamidation of o-amine with N,N’-dimethylformamide and C-H activation coupling type reaction of amide followed by cyclodehydration. This process seems to be suitable for construction of numerous 2-substituted benzoxazoles or benzothiazoles analogue with high throughput. And mechanism for the deduced from intermediates were introduced in the article.

Part 3: Design synthesis of listed drug – “Silodosin”. Enantioselective synthesis of clinically approved drug—Silodosin for the treatment of benign prostatic hyperplasia from the commercially available compounds 1-acetyl-5-(2-aminopropyl) indoline-7-carbonitrile 118 and 2-(2- (2,2,2-trifluoroethoxy)phenoxy)ethyl methanesulfonate 119 is explored.

Key step in the synthesis is chiral resolution of intermediate 120, which was achieved by a simple diastereomeric crystallization using (S)-(+)-mandelic acid assisted by ultrasonication. The present synthetic strategy has lesser number of steps and is vastly improved the overall yield in this short route towards target compound—Silodosin.