直接由SiO2低温合成含硅环氧化合物及其结构表征

研究了直接由SiO2(沉淀白炭黑)、乙二醇、KOH为原料低温合成高活性的五配位有机硅络合物[KSi-(OCH2CH2O)2OCH2CH2OH]然后与环氧氯丙烷反应,生成含硅环氧化合物,并借助于红外、核磁共振、热分析、能谱元素分析等现代测试手段,对合成的产物进行了结构表征。     

直接由SiO_2低温合成含硅聚氨酯及其结构表征

有机硅材料是一类应用非常广泛的材料,但这些产品所用基本原料几乎都来源于石英沙(SiO2)的高温碳热还原[1],这个方法已大规模的工业化,但它的高能耗、高腐蚀成为人们越来越关注的问题.1991年美国Laine[2]直接以SiO2为原料成功地制备了五配位、六配位有机硅化合物,并进一步合成了导电材料和高性能陶瓷[3～7].我们实验室自1995年以来,在Laine的基础上,发现如果以沙子为原料,则产率非常低,即使在超声波作用下,反应一周合成的五配位硅化合物其产率不足10%,这可能是由于沙子的晶型非常完美,在200℃下很难打破Si-O键生成配位硅,如果以无定型SiO2为原料(如白碳黑,稻壳灰等),合成的五配位硅其产率几乎为100%,而且反应时间缩短为4h.然后以高活性的五配位硅为原料制备了一系列的含硅有机物,如与环氯丙烷反应[8],不仅消除了五配位硅化合物的水解可逆性反应,中和了它的强碱性,而且把环氧基团接到了配位硅化合物上,生成了一种非常类似于液态环氧树脂的淡黄色的粘稠状液体.我们按Laine的路线,向含硅聚合物方向发展[9].本文合成的双羟基四配位硅单体是五配位硅钾化合物向含硅聚合物转化的关键,由于其结构带有两个活泼羟基,可以和二元酰氯、二元羧酸、二异氰酸酯、导氰酸酯基封端的聚醚或异氰酸酯基封端的聚酯进行缩聚反应,合成主连含硅的聚合物.     

含硅有机锗化合物的合成

报道了一类含硅有机锗化合物的合成。从Ｍｅ３ＳｉＣｌ，ＲＸ，ＧｅＯ２出发，经过氯化、格氏反应、亲核取代等反应，制得目标化合物－－二〔烃基二甲硅基甲基〕锗的二氯化物。它们的结构经元素分析和红外表征。     

直接由SiO2合成双羟基四配位硅化物及其结构表征

化合物;直接由SiO2合成双羟基四配位硅化物及其结构表征     

由Diels-Alder反应合成新型热稳定性含硅双马来酰亚胺──合成及表征

由Ｄｉｅｌｓ－Ａｌｄｅｒ反应合成新型热稳定性含硅双马来酰亚胺──合成及表征郝建军,江璐霞,蔡兴贤（四川联合大学材料科学与工程学院高分子材料系,成都,６１００６５）关键词双马来酰亚胺,有机硅,Ｄｉｅｌｓ－Ａｌｄｅｒ反应,合成,表征采用单体扩链增韧［１］...     

氟烷基三甲基硅化合物的合成和反应研究

羰基化合物的氟烷基化反应是把含氟基团引入有机分子中去的一个重要手段。文献报道的主要是通过氟烷基金属试剂来进行此反应。但氟烷基金属试剂不太稳定,容易分解。这就给它们的应用带来了许多不便。我们发现,氟烷基三甲基硅化合物(1)作为氟烷基阴离子前体,在比较温和的条件下,便可使醛发生氟烷基化反应。首先,参照文献方法,通过氟烷基格氏试剂与三甲基氯硅烷反应,方便地制得了两个新的氟烷基三甲基硅化合物 R_F-SiMe_3(1)。     

新型含硅唑类化合物的合成及杀菌活性

合成了２０个新型含硅唑类化合物，其化学结构经ＩＲ，ＭＳ，１ＨＮＭＲ和元素分析确证。生物活性测定显示一些化合物对棉花枯萎病菌等有较好的抑制活性，一些化合物对黄瓜灰霉病菌的抗性菌有很好的活性。讨论了化合物的结构与生物活性关系。     

含硅二烃基锡苯氧乙酸配合物的合成与结构表征

自从1980年Crowe[1]等首次报道了有机锡化合物具有较好的抗癌活性以来,人们合成了各种类型的有机锡化合物,并对它们的结构、物化性质和生物活性作了广泛的研究[2,3].大量的研究结果表明,二烃基锡化合物具有比其相应的单烃基锡、三烃基锡或四烃基锡化合物更好的抗癌活性;并且,分子中不同的烃基及配体对其生物活性都将产生一定的影响[4,5],尤其在水解、转移过程中,某些配体还可起到协同作用.     

新型桥连双卟啉化合物的合成及结构表征

通过将4,4′-二羧基-2,2′-联吡啶、2,6-二溴甲基吡啶、2,6-二羟甲基吡啶和1,8-二氨基萘分别与5-(4-羟基苯基)-10,15,20-三苯基卟啉(1a)、5-(4-甲酰苯基)-10,15,20-三苯基卟啉(1b)和5-[4-(4′-溴代丁氧基)苯基]-10,15,20-三苯基卟啉(1c)反应,合成了3类新型的双卟啉化合物2a-2e,经IR,¹HNMR,MS,UV-Vis光谱及元素分析对中间体和目标化合物的结构进行了表征.     

含硅不对称硫代磷酸酯及其碳类似物的合成与杀虫活性

合成了两个系列的含硅不对称硫代磷酸酯新化合物,研究了其杀虫活性,并合成了第2系列含硅化合物的碳类似物,对其¹H,³¹P NMR及杀虫活性进行了比较。.     

双羟基四配位硅单体的合成

以无定型二氧化硅为起始原料，与乙二醇、氢氧化钾反应，生成高反应活性的 五配位硅钾化合物，并以此为原料与2－氯乙醇反应制备了双羟基四配位硅化合物 。探讨了不同反应条件（如温度、不同反应物摩尔比、催化剂等）对该反应的影响 ，并对合成的化合物做了红外光谱、核磁共振（^1H,^13C)、元素分析、能谱元素 分析等结构表征。     

配位有机硅在聚醚氨酯中的应用

研究了直接从无定型二氧化硅出发,与乙二醇、氢氧化钾反应,生成高反应活性的五配位硅钾络合物,并以此为原料与2－氯乙醇反应制备双羟基四配位有机硅单体,该单体作为扩连剂再与异氰酸酯基封端的聚醚或聚酯进行低温溶液缩聚反应合成含硅聚醚氨酯,经红外光谱,热重分析,胶渗透色法测定分子量等对合成的物质作了结构表征,热重分析表明该聚合物的耐热性能有所提高,胶渗透色谱法测定分子量高于10万。     

新型三官能团脂环族环氧化合物的合成、表征及其阳离子引发光固化活性研究

以双环戊二烯等为原料合成一种新型三官能团液体脂环族环氧树脂. 通过红外光谱、 核磁共振氢谱及质谱等对其中间体及环氧树脂的结构进行了表征. 所得脂环族环氧树脂采用阳离子引发 剂二甲苯基碘鎓六氟磷酸盐引发进行紫外光固化, 对其光固化活性进行了研究, 同时讨论了氧化剂过氧化苯甲酰对该光固化体系的增感作用. 研究结果表明, 新合成的脂环族环氧树脂采用二甲苯基碘鎓六氟磷酸盐引发可以进行光固化, 过氧化苯甲酰明显地加快了其光固化速度, 固化膜具有较好的热稳定性.     

Self-Immolation of a Bacterial Dehydratase Enzyme by its Epoxide Product

Disabling the bacterial capacity to cause infection is an innovative approach that has attracted significant attention to fight against superbugs. A relevant target for anti-virulence drug discovery is the type I dehydroquinase (DHQ1) enzyme. It was shown that the 2-hydroxyethylammonium derivative 3 has in vitro activity since it causes the covalent modification of the catalytic lysine residue of DHQ1. As this compound does not bear reactive electrophilic centers, how the chemical modification occurs is intriguing. We report here an integrated approach, which involves biochemical studies, X-ray crystallography and computational studies on the reaction path using combined quantum mechanics/molecular mechanics Umbrella Sampling Molecular Dynamics, that evidences that DHQ1 catalyzes its self-immolation by transforming the unreactive 2-hydroxyethylammonium group in 3 into an epoxide that triggers the lysine covalent modification. This finding might open opportunities for the design of lysine-targeted irreversible inhibitors bearing a 2-hydroxyethylammonium moiety as an epoxide proform, which to our knowledge has not been reported previously.     

有机脲类快速固化环氧粉末涂料的研究

有机脲类化合物一般作为一种有效固化促进剂使用。但作者经大量的实验得出,有机脲类可以单独作为一种优良的快速固化剂,其固化速度快,并且有优良的附着性能。研究结果表明,有机脲类化合物ND作为快速潜伏性环氧树脂固化剂,在环氧粉末涂料中加入4%时,固化温度为180℃,粉料55秒可以完全固化。     

树枝状多氨基环氧树脂固化剂的合成及其固化行为

树枝状多氨基环氧树脂固化剂的合成及其固化行为;树枝状大分子;丙烯酸酯双键;乙二胺(EDA)     

Natural Product Synthesis at the Interface of Chemistry and Biology

Nature has evolved to produce unique and diverse natural products that possess high target affinity and specificity. Natural products have been the richest sources for novel modulators of biomolecular function. Since the chemical synthesis of urea by Wöhler, organic chemists have been intrigued by natural products, leading to the evolution of the field of natural product synthesis over the past two centuries. Natural product synthesis has enabled natural products to play an essential role in drug discovery and chemical biology. With the introduction of novel, innovative concepts and strategies for synthetic efficiency, natural product synthesis in the 21st century is well poised to address the challenges and complexities faced by natural product chemistry and will remain essential to progress in biomedical sciences.     

A Road Less Traveled to Functional Polymers: Epoxide Termination in Living Carbanionic Polymer Synthesis

Functional polymers possess tremendous potential both in academia and in industry. In particular, oxiranes offer manifold possibilities for the introduction of single hydroxyl or multiple orthogonal functionalities in carbanionic polymerization. Here, we present a brief overview of the fascinating possibilities arising from the employment of common as well as individually designed epoxide derivatives for the synthesis of end‐functional polymers. Continuous flow techniques can be utilized for the rapid generation and screening of precisely defined hydroxyl‐modified polymers. The utilization of functionalized polymers as precursors for the formation of complex macromolecular architectures (e.g., miktoarm star polymers) is summarized and potential applications as well as future perspectives are discussed.

     

Capturing Biological Activity in Natural Product Fragments by Chemical Synthesis

Natural products have had an immense influence on science and have directly led to the introduction of many drugs. Organic chemistry, and its unique ability to tailor natural products through synthesis, provides an extraordinary approach to unlock the full potential of natural products. In this Review, an approach based on natural product derived fragments is presented that can successfully address some of the current challenges in drug discovery. These fragments often display significantly reduced molecular weights, reduced structural complexity, a reduced number of synthetic steps, while retaining or even improving key biological parameters such as potency or selectivity. Examples from various stages of the drug development process up to the clinic are presented. In addition, this process can be leveraged by recent developments such as genome mining, antibody–drug conjugates, and computational approaches. All these concepts have the potential to identify the next generation of drug candidates inspired by natural products.