QSAR方法在研究香豆素前药释放与乙内酰脲化合物手性色谱行为方面的应用

发布时间：2018-03-17 23:20

本文选题：定量构效关系　切入点：前药　出处：《山东大学》2014年博士论文　论文类型：学位论文

【摘要】：近二十年来,定量构效关系的研究方法已广泛应用于药物、农药、环境等领域的研究。具体研究内容已从传统的药物结构与其生物活性的定量关系研究,扩展到包括预测药物的理化性质、药物动力学释放、药物的色谱保留行为等许多方面。特别是近年来量子化学计算方法(如DFT,Hartree-Fock等方法)的引入,进一步提高了定量构效关系对化合物结构特性预测的精确性。因此,结合药物的结构特性计算,运用统计学定量分析方法,可帮助科研工作者深入分析药物结构中影响药动学因素的关键问题,以及药物结构改变与色谱保留时间、流出顺序和手性分离的关键影响因素。本文第一部分研究工作是将量子化学计算方法DFT应用于香豆素前药释放系统的定量构效关系研究。该前药系统最初由本课题组开发,适于短肽在体内释放。它可被体内酯酶降解,继而引发分子内的环合内酯化反应,生成香豆素并释放氨基酸或短肽。实验室在前期研究工作中,曾对香豆素前药释放系统进行了大量结构修饰,并发现结构改变能够显著影响药物的释放速率。为了深入阐明这一现象,我们应用Gaussian 03软件的的量子化学计算方法(B3LYP/6-31+G(d,p)),获得了本实验室前期合成27个香豆素类前药的结构参数,然后分别应用线性回归和多项式神经网络等方法建立了 5个QSPR模型。其中两个线性模型分别为SMLR线性模型(q2=0.427,r2=0.516)和PLS线性模型(q2=0.584,r2=0.663)。其它3个非线性QSPR模型由多项式神经网络(PNN)模拟法建立(q2=0.692,0.675,0.663;r2=0.700,0.688,0.672)。相关结果表明,基于量子化学DFT计算的QSPR模型,尤其是PNN模型,可成功用于香豆素前药释放动力学的预测,为开发新型香豆素类前药候选物提供理论指导。本文第二部分的主要研究内容是3,5-二取代手性乙内酰脲的新型合成方法及其在手性色谱保留的QSAR研究。乙内酰脲作为一种重要的杂环化合物,已广泛出现在许多药物和天然产物结构之中。近年来还发现,3,5-二取代手性乙内酰脲化合物可作为手性配体用于催化不对称羟醛缩合和Mannich反应,具有广泛的用途。我们在实验中发现了一种新型3,5-二取代手性乙内酰脲化合物的合成方法。该方法以伯胺或芳胺为原料,先制得相应异腈酸酯,然后与氨基酸甲酯盐酸盐反应生成脲中间体,最后在不同碱催化下可以得到消旋或手性中心保持的3,5-二取代手性乙内酰脲化合物。特别是当应用无水四氢呋喃为溶剂,在-20℃低温和氢化钠催化下可得到构型保持的手性3,5-二取代乙内酰脲化合物。该方法具有反应步骤少、时间短、分离产率和ee%值高等特点,不仅适用于常见的N3位烷基取代的手性乙内酰脲化合物合成,还可用于N3位为芳基的相关衍生物合成,具有广泛的适用范围。在此基础上,我们研究了上述合成的11个手性化合物在两种多糖型手性固定相(ChiralpakIA柱和ChiralpakIC柱)的分离和保留规律。结果显示,含有不同取代基的手性乙内酰脲衍生物在手性色谱柱的保留行为有明显差异。另一方面,多糖类的固定相Chiralpak IA柱较Chiralpak IC柱表现出更好的手性识别能力。例如20%乙醇作为流动相改性剂时,Chiralpak IA柱可实现所有11个3,5-二取代手性乙内酰脲衍生物的手性拆分;而Chiralpak IC柱在常用的20%乙醇或20%异丙醇条件下,约有一半的目标化合物未能实现基线分离。我们还发现,3,5-二取代乙内酰脲化合物的手性色谱行为不仅与手性固定相有关,还受到极性改性剂和温度的影响。例如,应用不同的极性改性剂(如乙醇、丙醇、异丙醇和正丁醇)可导致同一个乙内酰脲类手性化合物在Chiralpak IA柱的保留行为各有差异,但一般先流出的光学异构体为S构型。在Chiralpak IC柱时,使用20%的乙醇为极性改性剂时,多数化合物的R构型先流出;而20%异丙醇为极性改性剂时,多数化合物S构型先流出。对于分离效果不好的化合物(如ChiralpakIA柱在20%异丙醇条件下,化合物4,6和9分离度不佳),降低极性改性剂浓度可改善部分化合物的手性分离效果。但应用Chiralpak IC柱时,部分分离效果不好的情况(如化合物7和11)即使在降低极性改性剂比例的情况下,仍未能实现基线分离。考虑到van't Hoff方程中温度对手性色谱柱的影响,我们推测部分化合物难以实现有效分离的原因,可能是由于在某种极性改性剂条件下,柱温接近其等对映体选择性温度(Tiso)而处于温度盲区。因此我们基于van't Hoff方程,测试了不同温度条件的实验数据,并计算出相应化合物在特定手性固定相和极性改性剂条件下的Tiso。研究结果显示,Chiralpak IA柱在20%异丙醇极性改性剂条件下,化合物6和9的Tiso分别为20.6℃和30.8℃,从而解释了这两个化合物在室温下应用20%异丙醇可出现对映异构体同时流出的现象,因此无法实现手性分离。类似的情况在Chiralpak IC柱上也同样存在。例如,化合物7在20%乙醇条件下的Tiso为20.3℃;化合物11在20%异丙醇条件下的Tiso为11.8℃。根据热力学有关原理,当化合物处于温度盲区时,通过改变温度和降低极性改性剂两种方法可以使手性分离条件远离盲区而实现基线分离,同时可以观察到两个光学异构体流出顺序反转的情况。在我们的实验中,结合温度改变和降低极性改性剂比例,不仅成功解决了部分化合物(Chiralpak IA柱化合物6和9;ChiralpakIC柱化合物7和11)在乙醇或异丙醇条件下的手性分离问题,而且首次报道了4个3,5-二取代手性乙内酰脲衍生物所产生的流出顺序反转现象。上述研究也为深入探讨多糖型手性固定相与手性乙内酰脲衍生物的分离机制提供了新的研究思路。为进一步探索3,5-二取代手性乙内酰脲衍生物的色谱保留机制,我们运用三维定量构效关系研究的比较分子力场分析方法(CoMFA),考察该类化合物的三维立体结构与其色谱保留因子之间的关系。通过选择最优参数进行运算,我们成功获得了 3,5-二取代手性乙内酰脲衍生物应用Chiralpak IA柱和Chiralpak IC柱时,以EtOH和IPA为流动相时的CoMFA模型,交叉验证系数q20.528,非交叉验证系数r20.926,均具有较好的预测能力。该模型为深入研究该类手性化合物的色谱保留行为提供的理论基础。
[Abstract]:In the past twenty years, the research method of quantitative structure-activity relationship has been widely used in medicine, pesticide, environment and other fields. The specific research contents from the traditional quantitative drug structure and biological activity studies, extended to include prediction of physicochemical properties of drugs, drug release kinetics, drug retention behavior many aspects. Especially in recent years, the quantum chemistry calculation method (such as DFT, Hartree-Fock and other methods) are introduced, further improve the accuracy of QSAR prediction on the structure of the compounds. Therefore, the characteristics of computing with drug nodes, using the method of quantitative analysis in statistics, can help researchers to deeply analyze the key issues affecting drug the dynamic factors of drug and drug structure, structure change and retention time, key factors influencing the elution order and chiral separation. In the first part of this research work The quantum chemistry calculation method DFT applied to quantitative coumarin prodrug delivery system of structure-activity relationship study. The prodrug system originally developed by our research group development, suitable for short peptides released in vivo. It can be esterase degradation, followed by esterification of intramolecular cyclization, formation of coumarin and release of amino acids or peptides laboratory. In previous study, the drug release system has coumarin before of the modified structure, and found that structural changes can significantly affect the release rate of the drug. In order to further elucidate this phenomenon, quantum chemistry calculation methods we used Gaussian 03 software (the B3LYP/6-31+G (D, P)), to obtain structural parameters the synthesis of 27 coumarin prodrugs in the laboratory, and then using linear regression and polynomial neural network method establishes 5 QSPR models. Two of them were SMLR linear model Linear model (q2=0.427, r2=0.516) and PLS linear model (q2=0.584, r2=0.663). The other 3 nonlinear QSPR model by polynomial neural network (PNN) simulation was established (q2=0.692,0.675,0.663; r2=0.700,0.688,0.672). The results show that the QSPR model based on DFT quantum chemical calculation, especially the PNN model can be successfully used for the prediction of coumarin before the drug release kinetics, to provide theoretical guidance for the development of novel coumarin prodrug candidates. The main research contents of the second part of this paper is a new method of synthesis of 3,5- two substituted chiral hydantoin and its QSAR in the study of chiral chromatographic retention. Hydantoin as an important heterocyclic compounds, have been widely found in many drugs and natural products. In recent years, also found that two 3,5- substituted chiral hydantoin compounds can be used as chiral ligands for catalytic asymmetric aldol condensation and anti Mannich We should, with a wide range of uses. We found a new synthesis method of 3,5- two substituted chiral hydantoin compounds in the experiment. The method of using primary amine or aromatic amine as raw materials, first prepared corresponding isocyanates, and amino acid methyl ester hydrochloride reacts urea intermediates, most in different base catalysis can get or keep the 3,5- racemic chiral center two substituted chiral hydantoin compounds. Especially when the application of anhydrous tetrahydrofuran as solvent, the catalytic -20 low temperature and sodium borohydride can be obtained under retention of configuration of chiral 3,5- two substituted hydantoin compounds. This method has less reaction steps, time is short, the separation efficiency and ee% value etc., not only applicable to common N3 chiral ethylene alkyl substituted hydantoin compounds, can also be used for the synthesis of N3 related derivatives for aryl, which has a wide application scope on the basis of this, We studied 11 chiral compounds in the synthesis of two kinds of polysaccharide based chiral stationary phase (ChiralpakIA column and ChiralpakIC column) separation and retention rules. The results showed that the chiral hydantoin derivatives with different substituents have obvious differences in the retention behavior of chiral column. On the other hand, polysaccharide fixed Chiralpak IA column Chiralpak IC column showed better chiral recognition ability. For example, 20% ethanol as mobile phase modifier, Chiralpak IA column can achieve all 11 3,5- two substituted chiral chiral hydantoin derivatives; and the Chiralpak IC column in isopropanol conditions of 20% ethanol or 20% commonly used under about half of the target compound, failed to achieve baseline separation. We also found that 3,5- two substituted chiral chromatographic behavior of hydantoin compounds not only with chiral stationary phase, but also by the polar modifier and temperature Impact. For example, the application of different polar modifiers (such as ethanol, propanol, and isopropanol butanol) can lead to the same kind of chiral hydantoin compounds have the difference in the retention behavior of Chiralpak IA column, but the optical isomers generally first out of the S configuration in the Chiralpak IC column. 20%, using ethanol as polar modifier, R configuration most compounds were first and 20% outflow; isopropanol as polar modifier, most compounds S configuration first outflow. The effect is not good for the separation of compounds (such as the ChiralpakIA column in 20% isopropanol conditions, compounds 4,6 and 9 degrees of separation poor), reduce the chiral separation of polar modifier can improve the concentration of some compounds. But the application of Chiralpak IC column, part of the separation effect is not good situation (such as compounds 7 and 11) even in the lower polar modifier of the proportion of cases failed to achieve baseline separation. Considering van't Effect of column temperature, the opponent in the Hoff equation, the reason we speculate that it is difficult to achieve effective separation of some compounds, probably due to some polar modifier conditions, the column temperature is close to the enantioselective temperature (Tiso) in the temperature zone. So we based on the van't Hoff equation, the experimental data at different temperatures the conditions of the test, and calculate the corresponding compounds in particular chiral stationary phase and polarity of the modified Tiso. results of agent under the condition of Chiralpak, IA in the 20% column of isopropanol modifier under the condition of Tiso 6 and 9 compounds were 20.6 degrees and 30.8 degrees, which can be explained to reflect at the same time, the phenomenon of outflow application of isomer 20% isopropanol these two compounds at room temperature, it is impossible to realize chiral separation at similar situation also exists in the Chiralpak IC column. For example, 7 compounds in 20% ethanol under the condition of Tis O is 20.3 DEG C; compound 11 in 20% isopropanol Tiso under the conditions of 11.8 DEG C. According to the principle of thermodynamics, the temperature when the compound is in the blind spot, by changing the temperature and reduce the polar modifier two ways to chiral separation conditions away from the blind area to achieve baseline separation, the same can be observed when the two optical reverse the order of outflow isomers. In our experiment, combining with the temperature change and reduce the polar modifier proportion, not only solved the compounds (compounds 6 and 9 Chiralpak IA column ChiralpakIC column; compounds 7 and 11) in the chiral separation of ethanol or isopropanol conditions, and reported for the first time. 4 3,5- two substituted chiral hydantoin derivatives produced by the elution order reversal phenomenon. The research is to further explore the separation mechanism of polysaccharide based chiral stationary phase and chiral hydantoin derivatives provide a new The ideas of the research. To further explore the 3,5- two substituted chiral hydantoin derivatives retention mechanism, we use comparative molecular three-dimensional quantitative structure-activity relationship field analysis method (CoMFA), the three-dimensional structure of this kind of compounds with retention factor between operations. By choosing the optimal parameters, we success of the 3,5- two substituted chiral hydantoin derivatives using Chiralpak IA column and Chiralpak IC column, with EtOH and IPA for the CoMFA model of mobile phase, the coefficient of cross validation q20.528, non cross validated coefficient r20.926 has good prediction ability. This model provides theoretical basis for further study of chromatographic retention behavior of the chiral compounds.

【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R917

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