用分子模构法建立κ阿片受体激动剂的药效基团

目的：建立非肽类κ阿片受体激动剂的药效基团。方法：从ＭＤＬ ＭＤＤＲ数据库中选出五个高活性非肽类κ阿片受体激动剂，以四氢吡咯环Ｎ原子和乙酰胺基团为叠加点，用分子模构法建立非肽类κ阿片受体激动剂的药效基团。结果：四氢吡咯环、乙酰胺的羰基和与惭酰胺相连的疏水基团为非肽类κ阿片受体激动剂共同结构特征。推测受体Ａｓｐ１３８与甲氢吡咯环的Ｎ原子构成氢键，Ｓｅｒ１８７可能与激动剂的乙酰胺羰基以氢键形式相作用。     

Establishment of kappa opioid receptor agonists pharmacophore with molecular modeling method

目的：建立非肽类κ阿片受体激动剂的药效基团．方法：从ＭＤＬＭＤＤＲ数据库中选出五个高活性非肽类κ阿片受体激动剂，以四氢吡咯环Ｎ原子和乙酰胺基团为叠加点，用分子模构法建立非肽类κ阿片受体激动剂的药效基团．结果：四氢吡咯环、乙酰胺的羰基和与乙酰胺相连的疏水基团为非肽类κ阿片受体激动剂共同结构特征．推测受体Ａｓｐ１３８与四氢吡咯环的Ｎ原子构成氢键，Ｓｅｒ１８７可能与激动剂的乙酰胺羰基以氢键形式相作用．与乙酰胺相连接的疏水性基团可能与受体有疏水作用．结论：建立的药效基团有助于设计新型高效κ阿片受体激动剂     

抗消化性溃疡病药物杂环甲醛缩氨(硫)脲和酰胺的合成和构效分析

呋喃唑酮是我国临床上发现并使用的抗消化道溃疡药物。为优化其活性,对呋喃唑酮分子中的硝基呋喃环和噁唑酮环进行了结构修饰和改造。合成的28个化合物的生物活性表明,用呋喃、噻吩、吡咯或甲基吡咯代替硝基呋喃环,用氮脲、氨硫脲和芳酰肼等结构片断替代噁唑酮环,均可引起活性和毒性的变化。构效关系分析表明,化合物的水溶解性和羰基的电荷密度是影响化合物活性的重要因素。     

κ阿片受体分子模拟及其与非肽类κ阿片激动剂的作用

目的：研究了κ阿片受体及其与非肽类激动剂的作用机制。方法;以细菌视紫红质为模板,模建κ阿片受体七个跨膜区的三维结构,将五个高活性非肽类激动剂对接以螺旋区内,研究作用机制。结果：（１）四氢吡咯环氮原子与Ａｓｐ１３８羧基成氢键;（２）乙酰胺羰基氧与受体Ｓｅｒ１８７间存在在氢键作用;（３）与乙酰胺相连的疏水基团处于由Ｖａｌ２３９,Ｖａｌ１２３６,Ｐｈｅ２３５,Ｖａｌ２３２,Ｌｅｕ１８６和Ｔｒｐ１８３构成     

Molecular modeling on kappa opioid receptor and its interaction with nonpeptide kappa opioid agonists 1

目的：研究κ阿片受体及其与非肽类激动剂的作用机制．方法：以细菌视紫红质为模板,模建κ阿片受体七个跨膜区的三维结构;将五个高活性非肽类激动剂对接到螺旋区内,研究作用机制．结果：（１）四氢吡咯环氮原子与Ａｓｐ１３８羧基成氢键;（２）乙酰胺羰基氧与受体Ｓｅｒ１８７间存在氢键作用;（３）与乙酰胺相连的疏水基团处于由Ｖａｌ２３９、Ｖａｌ２３６、Ｐｈｅ２３５、Ｖａｌ２３２、Ｌｅｕ１８６和Ｔｒｐ１８３构成的疏水区域内;（４）激动剂的四氢吡咯环为Ｉｌｅ２９０、Ａｓｐ１３８、Ｉｌｅ１９４、Ｉｌｅ１３５和Ｃｙｓ１３１残基包围．结论：模型将有助于设计新型高效安全的κ阿片受体激动剂．     

支气管松弛药溴(口恶)特罗(Broxaterol)

为了寻找一个理想的支气管扩张药,导致合成与试验了一大批基于异丙肾上腺素结构的化合物,以延长支气管扩张作用和增强β_2-选择性,从而减少因兴奋β_1-而引起的副作用发生率。最近,制备了侧链与特布他林或者舒喘宁相似的一系列化合物。这些化合物证明对β-肾上腺素能受体有较高的亲和力,溴噁特罗为其中之一,被选出作进一步评价。合成 3-溴-5-异噁唑酰氯(Ⅰ)与丙二酸二乙酯(Ⅱ)缩合得相应的丙二酰衍生物(Ⅲ),Ⅲ经脱羧水解后生成5-乙酰基-3-溴异噁唑(Ⅳ)。Ⅳ经溴化得5-溴乙酰基-3-溴异噁唑     

1-(1H-1,2,4-三唑-1-基)-(2,4-二氟苯基)-3-取代-2-丙醇类化合物的合成及其抗真菌活性

目的研究不同取代哌啶和环仲胺侧链的引入对三唑醇类化合物抗真菌活性的影响。方法以氟康唑为先导化合物,设计合成了9个三唑醇类新化合物,化合物的结构均通过核磁、红外光谱确证;选择8种真菌为实验菌株,根据美国国家临床实验室标准委员会(NCCLS)推荐的标准化抗真菌敏感性实验方法,进行体外抑菌活性测试。结果目标化合物对8种真菌特别是深部真菌均有一定的抑制作用,其中化合物4、5对白色念珠菌的MIC80值小于或等于0.125μg.mL-1,是氟康唑活性的4倍以上,与伊曲康唑活性相当。结论立体化学因素的改变对该类化合物体外抑菌活性有较大影响。     

1,4-双[(5-芳基-1,3,4-噁二唑-2-)亚甲基]哌嗪的合成及其抗菌活性

目的研究多杂环化合物的合成方法和抗菌活性.方法将2-芳基-5-氯甲基-1,3,4-噁二唑(h～1n)与哌嗪缩合得相应的双取代哌嗪目标化合物(2a～2n).用试管稀释法,研究目标化合物的体外抑菌活性.结果合成了14个新化合物,其结构经MS、IR、1H-NMR和元素分析确证.多数化合物在体外表现出较好的抑菌活性.结论双噁二唑杂环取代的哌嗪化合物有可能成为新型结构的抗菌药物.     

异噁唑衍生物的合成及其抗菌活性研究

目的 设计并合成异噁唑衍生物,并对其体外抗菌活性进行了初步评价.方法 以3,4-二氟苯甲醛、盐酸羟胺为起始原料,经多步反应合成目标化合物.以利奈唑胺为阳性对照药,对目标化合物的抗菌活性进行评价.结果 合成了9个新化合物,其结构经1H-NMR、MS确证,体外活性测试结果显示,有1个化合物有显著的抗菌活性,与利奈唑胺相当.结论 体外活性试验表明,含异噁唑的所制备化合物作为新型的抗菌剂,其构效关系值得进一步研究.     

新3,5-二取代噁唑烷酮抗菌剂的合成及其体外抑菌活性

目的设计、合成噁唑烷酮新化合物并测定其体外抑菌活性.方法对文献方法进行了改进,在文献报道的构效关系基础上,设计、合成噁唑烷酮新化合物并测定体外抑菌活性.结果合成了39个新化合物,其中目标物18个,其结构经IR,1HNMR,MS等方法确证.16个化合物显示出较好的抑菌活性,其中化合物9,10,10b对4种试验菌的MIC50和 MIC90值小于或接近4种对照药,化合物9a和11c没有抑菌活性.结论化合物9,10和10b值得进一步研究.     

A High Energy X-ray Diffraction Study of Amorphous Indomethacin

Amorphous pharmaceuticals often possess a wide range of molecular conformations and bonding arrangements. The x-ray pair distribution function (PDF) method is a powerful technique for the characterization of variations in both intra-molecular and inter-molecular packing arrangements. Here, the x-ray PDF of amorphous Indomethacin is shown to be particularly sensitive to the preferred orientations of the chlorobenzyl ring found in isomers in the crystalline state. In some cases, the chlorobenzyl ring has no preferred torsional angle in the amorphous form, while in others evidence of distinct isomer orientations are observed. Amorphous samples with no preferred torsion angles of the chlorobenzyl ring are found to favor enhanced inter-molecular hydrogen bonding, and this is reflected in the intensity of the first sharp diffraction peak. These significant variations in structure rule out amorphous Indomethacin as a possible standard for x-ray PDF measurements. At high humidity, time resolved PDF's for >40 h reveal water molecules forming hydrogen bonds with Indomethacin molecules. A simple linear hydrogen bond model indicates that water molecules in the wet amorphous form have similar hydrogen bond strengths to those found between Indomethacin dimers or chains in the dry amorphous form.     

New isoxazole derivatives with a potent and selective beta 2-adrenergic activity

A series of 1-(3-subst-5-isoxazolyl)-2-alkylaminoethanol derivatives was synthesized and tested in order to evaluate the effectiveness of the isoxazole ring in replacing the catechol moiety of beta-adrenergic compounds. Direct binding studies and the influence on beta-receptors mediated responses in isolated guinea-pig atria and guinea-pig trachea were investigated to determine the pharmacological profile of the new derivatives. The results indicate that some derivatives with proper substitution in the isoxazole ring and in the aminoalcohol chain displayed a marked selectivity towards beta 2 tracheal receptors. In vivo studies confirmed this profile, and the derivative 1-(3-bromo-5-isoxazolyl)-2-tert.butyl aminoethanol hydrochloride was selected and further developed as a potential bronchodilatory agent.     

In vitro metabolism studies on the isoxazole ring scission in the anti-inflammatory agent lefluonomide to its active alpha-cyanoenol metabolite A771726: mechanistic similarities with the cytochrome P450-catalyzed dehydration of aldoximes.

The 3-unsubstituted isoxazole ring in the anti-inflammatory drug leflunomide undergoes a unique N-O bond cleavage to the active alpha-cyanoenol metabolite A771726, which resides in the same oxidation state as the parent. In vitro studies were conducted to characterize drug-metabolizing enzyme(s) responsible for ring opening and to gain insight into the mechanism of ring opening. Under physiological conditions, leflunomide was converted to A771726 in rat and human plasma (rat plasma,t1/2 = 36 min; human plasma, t1/2 = 12 min) and whole blood (rat blood, t1/2 = 59 min; human blood, t1/2 = 43 min). Human serum albumin also catalyzed A771726 formation, albeit at a much slower rate (t1/2 = 110 min). Rat and human liver microsomes also demonstrated NADPH-dependent A771726 formation (human liver microsomes, Vmax = 1797 pmol/min/mg and Km = 274 microM). Leflunomide metabolism in microsomes was sensitive to furafylline treatment, suggesting p4501A2 involvement. 3-Methylleflunomide, which contained a 3-methyl substituent on the isoxazole ring, was resistant to ring opening in base, plasma, blood, and liver microsomes. In microsomes, two monohydroxylated metabolites were formed, and metabolite identification studies established the 3- and the 5-methyl groups on the isoxazole ring as sites of hydroxylation. These results indicate that the C3-H in leflunomide is essential for ring opening. Although A771726 formation in human liver microsomes or recombinant p4501A2 required NADPH, its formation was greatly reduced by oxygen or carbon monoxide, suggesting that the isoxazole ring opening was catalyzed by the p450Fe(II) form of the enzyme. A mechanism for the p450-mediated ring scission is proposed in which the isoxazole ring nitrogen or oxygen coordinates to the reduced form of the heme followed by charge transfer from p450Fe(II) to the C=N bond or deprotonation of the C3-H, which results in a cleavage of the N-O bond.     

Solubility enhancement of phenol and phenol derivatives in perfluorooctyl bromide

Perfluorinated solvents are gaining popularity as pulmonary ventilation fluids, but they suffer from poor solvent quality in concurrent drug delivery applications. The present study examines the use of a hydrophobic solubilizing agent capable of interacting with model drug solutes by hydrogen bonding with the purpose of enhancing solubility in perfluorooctyl bromide (PFOB). A series of solubilizing agents containing a ketone carbonyl to act as a hydrogen bond acceptor and a perfluoroalkyl chain to maintain the solubility of the putative complex in PFOB are investigated. The solubility of phenol in PFOB is enhanced to the greatest extent by 1-(4-perfluorobutyl phenyl)-1-hexanone (III) where the ketone carbonyl is protected from the electron withdrawing effects of the perfluorobutyl chain by a phenyl ring. Experiments with solubilizers lacking the ketone group suggest that pi-pi bond interactions of III with phenol do not significantly enhance solubility. For a series of phenol derivatives, a rank-order correlation exists between the magnitude of solubility enhancement by III, as reflected by the calculated association constants, and the Hammett sigma parameter of the phenols. Because the O-methyl-substituted phenols do not have the ability to hydrogen bond, their solubility is not enhanced by the presence of III. The results of the present study indicate that solubility of model drug hydrogen bond donating compounds can be enhanced in PFOB by the presence of fluorocarbon-soluble hydrogen bond acceptors.     

Interaction of arylpiperazines with the dopamine receptor D2 binding site

The docking of several 1-benzyl-4-arylpiperazines to the dopamine receptor (DAR) D2 was examined. The results demonstrated that the interaction of protonated N1 of the piperazine ring with Asp 86 (III.32) and edge-to-face interactions of the aromatic ring of the arylpiperazine part of the ligand with Phe 178 (VI.44), Trp 182 (VI.48) and Tyr 216 (VII.58) of the receptor, represent the major stabilizing forces. Besides, the hydrogen bond acceptor group in position 2 of the phenylpiperazine aromatic ring could build one more hydrogen bond with Trp 182 (VI.48). Bulky substituents in position 4 were not tolerated due to the unfavorable sterical interaction with Phe 178 (VI.44). Substituents in position 2 and 3 were found to be sterically well tolerated. Introduction of electron attractive -NO2 group in position 3 of aryipiperazines decreased, while electron donors (-OMe) and the second aromatic ring (naphthyl) increased the binding affinity comparing to that of the phenylpiperazine 1. This can be explained in terms of favoured edge-to-face interactions in ligands with a high negative electrostatic surface potential (ESP) in the centre of aromatic residue of arylpiperazines. Thus, besides the salt bridges and hydrogen bonds, edge-to-face interactions significantly contribute to arylpiperazine ligands to form complexes with the DAR D2. Phe 178 (VI.44), Trp 182 (VI.48) and Tyr 216 (VII.58) can be considered as a part of the ancillary DAR D2 pocket preserved in most G protein-coupled receptors of the A class and obviously, the arylpiperazine structural motif represents one of the privileged structures that bind to this pocket.     

The discovery of novel vascular endothelial growth factor receptor tyrosine kinases inhibitors: pharmacophore modeling, virtual screening and docking studies

We have applied pharmacophore generation, database searching and docking methodologies to discover new structures for the design of vascular endothelial growth factor receptors, the tyrosine kinase insert domain-containing receptor kinase inhibitors. The chemical function based pharmacophore models were built for kinase insert domain-containing receptor kinase inhibitors from a set of 10 known inhibitors using the algorithm HipHop, which is implemented in the CATALYST software. The highest scoring HipHop model consists of four features: one hydrophobic, one hydrogen bond acceptor, one hydrogen bond donor and one ring aromatic function. Using the algorithm CatShape within CATALYST, the bound conformation of 4-amino-furo [2, 3-d] pyrimidine binding to kinase insert domain-containing receptor kinase was used to generate a shape query. A merged shape and hypothesis query that is in an appropriate alignment was then built. The combined shape and hypothesis model was used as a query to search Maybridge database for other potential lead compounds. A total of 39 compounds were retrieved as hits. The hits obtained were docked into kinase insert domain-containing receptor kinase active site. One novel potential lead was proposed based on CATALYST fit value, LigandFit docking scores, and examination of how the hit retain key interactions known to be required for kinase binding. This compound inhibited vascular endothelial growth factor stimulated kinase insert domain-containing receptor phosphorylation in human umbilical vein endothelial cells.     

1,4- and 2,4-substituted-1,2,3-triazoles as potential potassium channel activators. VII

New 1,4- and 2,4-substituted 1,2,3-triazole derivatives were synthesized and tested as potential BK(Ca) channel openers, as a part of a research program, which hypothesizes a pharmacophoric structure containing the 1,2,3-triazole ring. The structure-activity relationships were studied introducing some structural changes concerning molecular geometry and the presence of a hydrogen bond donor as a primary amino group and a phenolic or alcoholic hydroxy function. The compounds were prepared by nucleophilic substitution on the 1,2,3-triazole ring and by 1,3-dipolar cycloaddition of azides to selected alkynes and to phenylacetone. The new compounds tested on rat aortic rings did not exhibit any significant vasorelaxing activity.     

Discovery, synthesis, and biological evaluation of a novel group of selective inhibitors of filoviral entry

Herein, we report the development of an antifiloviral screening system, based on a pseudotyping strategy, and its application in the discovery of a novel group of small molecules that selectively inhibit the Ebola and Marburg glycoprotein (GP)-mediated infection of human cells. Using Ebola Zaire GP-pseudotyped HIV particles bearing a luciferase reporter gene and 293T cells, a library of 237 small molecules was screened for inhibition of GP-mediated viral entry. From this assay, lead compound 8a was identified as a selective inhibitor of filoviral entry with an IC(50) of 30 μM. To analyze functional group requirements for efficacy, a structure-activity relationship analysis of this 3,5-disubstituted isoxazole was then conducted with 56 isoxazole and triazole derivatives prepared using "click" chemistry. This study revealed that while the isoxazole ring can be replaced by a triazole system, the 5-(diethylamino)acetamido substituent found in 8a is required for inhibition of viral-cell entry. Variation of the 3-aryl substituent provided a number of more potent antiviral agents with IC(50) values ranging to 2.5 μM. Lead compound 8a and three of its derivatives were also found to block the Marburg glycoprotein (GP)-mediated infection of human cells.