1-苄基4-苯基喹唑啉酮衍生物作為磷酸二酯酶抑制劑之設計合成與生物活性評估

Design, Synthesis and Biological Evaluation of 1-Benzyl-4-phenyl-1H-quinazolin-2-one Derivatives as Phosphodiesterase Inhibitors

賴信羽(Shin-Yu Lai)

指導教授 ： 陳基旺

國立臺灣大學/醫學院/藥學研究所/博士(2007年)

https://doi.org/10.6342/NTU.2007.10512

摘要

環磷酸腺苷 (c-AMP，c-GMP)在訊息傳遞中扮演相當重要的角色，其代謝則由磷酸二酯酶 (Phosphodiesterases, PDEs)水解成開環形式的磷酸腺苷。因此若能調控磷酸二酯酶的活性則在臨床上有很多的治療用途。而在臨床的研究中PDEs的抑制劑已被用來做心血管、氣喘、免疫及陽痿方面的治療，而近年來雙專一型的PDEs抑制劑也成為心血管及氣喘治療的新研究趨勢。本論文主要是針對由早期經由實驗室隨機篩選而得到的PDE4、PDE5 (IC50 = 4.6, 6.3 mM)雙效抑制劑1-(4-methoxybenzyl)-4-phenyl-1H-quinazolin- 2-one (35) 進行構效關係的研究。在這一系列的研究中，總共合成了1H-quinazolin-2-one、1H-quinolin-2-one、1H-pyrido[4,3-d] pyrimidin-2-one、 1H-[1,8] naphthyridin-2-one、1H,8H-[1,8]naphthyridine-2,7-dione及 1H-benzo[4,5]furo[3,2-d] pyrimidin-2-one為主環架構的衍生物。而根據先導化合物35的結構，1H-quinazolin-2-one上第一、二、三、四、六、七及八位置已做相關修飾並研究其取代基效應。而由於反應中間體的不安定性及弱反應性，5-hydroxymethyl-2-furyl的取代基一直無法成功的置於1H-quinazolin-2-one的第四位置。經由對先導化合物35做系統性的結構修飾及電腦輔助藥物設計的研究，我們得到了強效的PDE4抑制劑 (IC50 = 12 nM)化合物148d以及PDE5抑制劑 (IC50 = 0.1 mM)化合物140c。而經由構效關係及電腦模擬的分析， 1H-quinazolin-2-one的第七位置有甲氧基取代以及保留第六位置上的氫原子則對PDE4的抑制活性有戲劇性增強的效果，而若於其第七位置上有甲氧基取代以及以溴原子取代於第六位置則會增強PDE5的抑制活性。而這樣的發現將來可有助於對選擇性磷酸二酯酶抑制劑的設計。另外本實驗室根據PDE5-抑制劑的X-ray結晶結構進行策略性的虛擬篩選並在活性測試後找出新型具有PDE4、5抑制活性的先導化合物。為了研究這些quinazolinone架構的化合物於氣喘及慢性阻塞性肺疾治療的應用價值，未來也會進行相關的細胞及動物層級實驗。除此之外，這些化合物也將會做s-GC活化及Maxi-K channel opening的相關活性評估來了解這一系列的化合物是否可透過雙重以上的機轉來治療男性勃起不全。

關鍵字

環磷酸腺苷 ； 磷酸二酯酶 ； 雙專一型抑制劑 ； 電腦輔助藥物設計 ； 1H-quinazolin-2-one ； 虛擬篩選

並列摘要

Phosphodiesterases (PDEs) can hydrolyze the cyclic nucleotide c-AMP or c-GMP that plays important roles in signal transductions. Therefore, PDEs represent potential therapeutic targets for a variety of diseases. PDE inhibitors have been studied in clinic for the treatments of cardiovascular, airway and inflammatory diseases as well as erectile dysfunction. Recently, new therapeutic strategies by using dual-specificity PDE inhibitors have been investigated for more beneficial treatments of cardiovascular disease and asthma. This thesis focuses on the structure-activity relationship (SAR) studies of 1-(4-methoxybenzyl)-4-phenyl-1H- quinazolin-2-one (35), a lead compound as PDE4 and PDE5 inhibitors (IC50: 4.6 and 6.3 micro;M, respectively) previously identified in our laboratory. Compounds bearing various heterocycle scaffolds including 1H-quinazolin-2-one, 1H-quinolin-2-one, 1H-pyrido [2,3-d]pyrimidin-2-one, 1H-pyrido[4,3-d]pyrimidin-2-one, 1H-[1,8]naphthyridin-2-one, 1H, 8H-[1,8]naphthyridine-2,7-dione, and 1H-benzo[4,5]furo[3,2-d]pyrimidin-2-one have been synthesized. Based on lead compound 35, the structural modifications were carried out to study the effects of substitutions at the 1-, 2-, 3-, 4-, 6-, 7-, 8-positions of 1H-quinazolin-2-one on the PDE inhibitory activities of compounds. Attempts to synthesize compounds with a 5-hydroxymethyl-2-furyl group at the 4-position of 1H-quinazolin-2-one were not successful due to structural instability and poor reactivity of the intermediates. Through structural modifications of lead compound 35 and computer-aided drug design, compound 148d was identified as the most potent PDE4 inhibitor with an IC50 of 12 nM, and compound 140c was the most PDE5 inhibitor with an IC50 of 0.1 mM. Based on SAR studies and molecular modeling, we can conclude that 7-methoxy substitution along with 6-unsubstitution of 1H-quinazolin-2-one derivatives could lead to a dramatic increase in inhibitory activity against PDE4, and that 7-methoxy substitution together with 6-bromo substitution was favorable for PDE5 inhibition. These findings could be applied in the design of selective inhibitors. Besides, we also performed virtual screening using the X-ray crystal structure of PDE5 and found new scaffold leads with PDE4 and PDE5 inhibitory activities. In the future, these quinazolinone-based PDE4 and PDE5 inhibitors will be test in cellular and animal models for their potential therapeutic applications to asthma and COPD. Moreover, these compounds will also be evaluated for the biological activities in s-GC activation and in Maxi-K channel opening to understand dual or triple mechanism for the treatment in erectile dysfunction.

並列關鍵字

cyclic nucleotide ； Phosphodiesterases (PDEs) ； dual-specificity inhibitors ； computer-aided drug design ； 1H-quinazolin-2-one ； virtual screening

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