一些嘧啶酰胺的合成及其生物活性

嘧啶环是生物活性化合物中具有较好生理活性的基因。本文试图将嘧啶环引入农用药剂,合成系列酰胺类化合物。生物试验结果表明,其中一些化合物具有杀蝇效能,一些化合物对较难防治的寄生疫霉具有良好的抑制效能。     

嘧啶（硫）醚类化合物的合成及除草活性

以2,4-二氯嘧啶为起始物设计并合成了一系列4-芳(硫)氧基-2-氯嘧啶和4-芳氧基-2-二甲氨基嘧啶化合物。利用2,4-二氯嘧啶2个氯原子的活性差异,酚取代嘧啶环上4位氯原子,然后二甲氨基取代2位的氯原子。所合成的化合物均经过了1H NMR和元素分析确证。为了确证酚首先在嘧啶环的4位发生亲核取代反应,用X衍射法测定了化合物3d的单晶结构。初步生物活性测定结果表明,大部分化合物都表现出一定的除草活性,其中化合物7c、7j、7k和7m在1.0×10-4g/mL质量浓度下对油菜的抑制率达到了80%以上。     

一锅法三组分合成2,4,6-三取代嘧啶的研究

嘧啶类化合物是一类含氮杂环化合物,具有强烈的生理和药理活性的。本文以苯乙炔、酰氯、甲脒为原料,通过偶联–环缩合两步一锅法合成2,4,6-三取代嘧啶。首先,酰氯和苯乙炔在Pd(PPh_3)_2Cl_2/Cu I的催化下原位生成炔酮,进而与甲脒发生环缩合反应得到嘧啶,所得产物的分离收率为33~50%。该方法具有较好的底物适用性、中等收率,为该类化合物的合成提供了一种简便有效的合成方法。     

嘧啶并嘧啶类化合物的合成研究进展

综述了近几十年来在医药和农药领域具有广泛用途的嘧啶并嘧啶类化合物的合成研究进展,介绍了三大类嘧啶并嘧啶类化合物的主要结构类型:嘧啶并[1,2-a]嘧啶类化合物、嘧啶并[4,5-d]嘧啶类化合物、嘧啶并[5,4-d]嘧啶类化合物的相关合成方法及新进展.     

新三取代嘧啶苯磺酰脲衍生物的合成与生物活性

设计合成了22个具有4,5,6-三取代嘧啶磺酰脲衍生物, 其结构经1H NMR, MS和元素分析确证. 经盆栽试验测定了化合物的除草活性, 结果表明, 嘧啶环5位取代基的引入对分子除草活性有一定的影响.     

4-(2′-呋喃甲基)氨基嘧啶衍生物的合成及生理活性

细胞分裂素可以促进植物的细胞分裂、延缓叶绿素的降解及其它老化过程[1 ] 。常见的细胞分裂素有玉米素 (Zeatin)、激动素 (Kinetin)、6 苄氨基嘌呤 ( 6 BA)等 ,这些物质中均含有嘌呤环。鉴于嘌呤环和嘧啶环均为核酸的碱基成分、激动素中含有 2′ 呋喃甲基 ,本文利用活性结构拼接原理 ,将该类细胞分裂素的嘌呤环换成嘧啶环 ,合成了 2种 4 ( 2′ 呋喃甲基 )氨基嘧啶衍生物 ,以试验其生理活性。目标化合物的合成路线如下。a:R =H　b :R =SCH31　实验部分1 .1　合成实验6 甲基 4 羟基嘧啶 (IIa) 1 ) 　 8 6g 6 甲基 4 羟基 2 巯基嘧啶 ,…     

选择性合成双[噻吩并[2,3-d]嘧啶-4(3H)-酮]

以2-氨基-4-三氟甲基-5-甲基-噻吩-3-羧酸乙酯(1)为起始原料制得膦亚胺2.在碳酸钾的催化下,膦亚胺2与芳基异氰酸酯和伯二胺的氮杂Wittig反应制得嘧啶环上2,2’取代的双[噻吩并[2,3-d]嘧啶-4(3H)-酮]3;膦亚胺2与烷基异氰酸酯和伯二胺的氮杂Wittig反应制得嘧啶环上3,3’取代的双[噻吩并[2,3-d]嘧啶-4(3H)-酮]4.化合物3的核磁共振氢谱表明关环反应在嘧啶环的2,2’位;化合物4的核磁共振氢谱表明关环反应在嘧啶环的3,3’位.对合成反应机理的推导及目标产物核磁共振氢谱数据的分析解释了此合成反应的选择性.     

新型非酯型拟除虫菊酯类化合物的合成及其生物活性的研究(Ⅰ)

传统的拟除虫菊酯类杀虫剂均含有1个酯基。近些年来,相继合成了一些非酯型拟除虫菊酯化合物。在保持分子整体空间结构不变的情况下,用其它功能团替换酯基,已开发出肟醚菊酯、醚菊酯、烃菊酯和酮菊酯等高效低毒、结构简化的杀虫剂,其中醚菊酯已正式作为农药商品。作为拟除虫菊酯类化合物结构变化的新尝试,我们合成了10种非酯型拟除虫菊酯新化合物,它们属于N-芳基-3-甲基-3-(对乙氧基苯基)丁酰胺类化合物,结构如下:     

含吡啶环拟除虫菊酯的合成及其杀虫杀螨活性

在新农药的创制中 ,吡啶作为苯环的生物等排体常被用作分子设计的有效基团 [1,2 ] ,近年来若干含有吡啶环的高效农药如吡虫啉 (Imidacloprid) [3 ] 、盖草能 (Haloxyfop) [4 ] 、啶氧菌酯 (Picoxystrobin) [5]等已被开发应用 .为合成筛选高生物活性化合物 ,我们在前期研究[6 ,7] 的基础上 ,将吡啶环引入拟除虫菊酯的酸部分 ,合成了与戊菊酯 (S- 5 4 3 9) [8] 和氰戊菊酯 (Fenvalerate) [8] 结构相近的新化合物 (5 ,6 ) ,并分离得到化合物 6的两对对映异构体 (α-和β-体 ) .生物活性测试表明 ,这些新化合物具有较高的杀虫或杀螨活性 .目标…     

新型非酯型拟除虫菊酯的合成

传统拟除虫菊酯类杀虫剂均含有一个酯基^[1,2],近年来,在保持分子整体空间结构不变的情况下,用其它功能基替换酯基,合成了非酯型的拟除虫菊酯^[3],式1所示结构的化合物具有良好的生物活性^[4],其中碳碳键或碳氧键 取代了传统拟除虫菊酯中的酯基,在主链结构上含有偕二甲基和3－苯氧基苯基,二是该结构中决定生物活性的主要基因^[5,6],在此结构的基础上已醚菊酯^[6],烃菊酯^[4]和酮菊酯^[7]等高效低毒,结构简化的除除虫菊酯类杀虫剂,而醚菊酯MTI－800已商品化,作为式1所示结构 新尝试,我们在保留2在性部分外,用环戊烯基取代直链烯烃,合成了一种非酯型的拟除虫菊酯（即1－甲基－1－苯基－1－[3-（3－苯氧基）苯基]环戊烯基－乙烷）（9）,其合成路线如式2。     

空气电极改性TiO2光催化剂的研究

将TiO2/C光催化剂负载在具有合成H2O2性能的空气电极上形成双功能新型复合电极.TiO2/C光催化层的微多孔特性使新型载体保持了高效合成H2O2的优势,J=15mA/cm2时,电流效率达到82%.新型载体又为TiO2/C光催化剂获得了阳极偏压,有利于将光生电子迅速导入载体,减少了光生载流子的复合.在新型光催化体系中,光化学氧化作用与光催化氧化作用有机地统一在同一电极/溶液界面附近,造成了该界面的强氧化环境,从而使有机分子的氧化降解速度得到显著提高.     

Structure-based design,synthesis of novel inhibitors of Mycobacterium tuberculosis FabH as potential anti-tuberculosis agents

Mycobacterium tuberculosis FabH,an essential enzyme in mycolic acids biosynthetic pathway,is an attractive target for novel anti-tuberculosis agents.Structure-based design,synthesis of novel inhibitors of mtFabH was reported in this paper.A novel scaffold structure was designed,and 12 candidate compounds that displayed favorable binding with the active site were identified and synthesized.     

Activity‐Directed Synthesis with Intermolecular Reactions: Development of a Fragment into a Range of Androgen Receptor Agonists

Activity‐directed synthesis (ADS), a novel discovery approach in which bioactive molecules emerge in parallel with associated syntheses, was exploited to develop a weakly binding fragment into novel androgen receptor agonists. Harnessing promiscuous intermolecular reactions of carbenoid compounds enabled highly efficient exploration of chemical space. Four substrates were prepared, yet exploited in 326 reactions to explore diverse chemical space; guided by bioactivity alone, the products of just nine of the reactions were purified to reveal diverse novel agonists with up to 125‐fold improved activity. Remarkably, one agonist stemmed from a novel enantioselective transformation; this is the first time that an asymmetric reaction has been discovered solely on the basis of the biological activity of the product. It was shown that ADS is a significant addition to the lead generation toolkit, enabling the efficient and rapid discovery of novel, yet synthetically accessible, bioactive chemotypes.     

Unprecedented Combination of Polyketide Natural Product Fragments Identifies the New Hedgehog Signaling Pathway Inhibitor Grismonone

Pseudo-natural products (pseudo-NPs) are de novo combinations of natural product (NP) fragments that define novel bioactive chemotypes. For their discovery, new design principles are being sought. Previously, pseudo-NPs were synthesized by the combination of fragments originating from biosynthetically unrelated NPs to guarantee structural novelty and novel bioactivity. We report the combination of fragments from biosynthetically related NPs in novel arrangements to yield a novel chemotype with activity not shared by the guiding fragments. We describe the synthesis of the polyketide pseudo-NP grismonone and identify it as a structurally novel and potent inhibitor of Hedgehog signaling. The insight that the de novo combination of fragments derived from biosynthetically related NPs may also yield new biologically relevant compound classes with unexpected bioactivity may be considered a chemical extension or diversion of existing biosynthetic pathways and greatly expands the opportunities for exploration of biologically relevant chemical space by means of the pseudo-NP principle.     

A Facile Synthesis of Novel Benzofuranyl Benzimidazole Derivatives

In this article, we report a facile route for the synthesis of novel benzofuranyl benzimidazole derivatives. The methodology involves the Sonagashira reaction of 2‐(3‐iodo‐4‐methoxyphenyl)‐1H‐benzimidazole ( 3 ) with variety of terminal alkynes to have novel benzimidazole alkynyl derivatives followed by iodo‐cyclisation to give novel iodo benzofuranyl benzimidazole derivatives. The resulting iodo benzofuranyl benzimidazoles were functionalized further via palladium mediated carbon–carbon bond formation for molecular diversity generating novel heterocyclic compounds.     

Highly functionalised organolithium and organoboron reagents for the preparation of enantiomerically pure α-amino acids

Homochiral, highly functionalised organolithium reagents derived from l-serine have been generated and reacted with electrophiles. The novel enantiomerically pure adducts thus obtained were then converted, through β-amino alcohols, into novel non-proteinogenic α-amino acids. The methodology also made available a novel boronic acid which was then employed as a Suzuki cross-coupling partner, elaborating a new pathway to phenylalanine analogues.     

Hierarchical ZnO/Cu "corn-like" materials with high photodegradation and antibacterial capability under visible light

A novel hierarchical ZnO/Cu "corn-like" material was successfully synthesized via facile low temperature hydrothermal and photo-deposition methods. This novel hierarchical material was well characterized by FESEM, XRD, EDS, UV-Vis. This novel material displayed high photodegradation and antibacterial capability under the irradiation of visible light. This is owing to its unique properties, including maximized light utilization rate via red-shifting the light absorption spectrum, enhanced specific surface area for mass transfer and reaction sites, and retarded recombination of photogenerated electrons and holes. Moreover, this novel hierarchical ZnO/Cu "corn-like" material demonstrated easy recovery from treated water for reuse. All these excellent properties indicate that this novel hierarchical ZnO/Cu "corn-like" material has a bright future in water purification applications.     

Investigation of a novel MEA for direct dimethyl ether fuel cell

In this study, we presented the novel membrane electrode assembly (MEA) for direct dimethyl ether fuel cell (DDFC). The anode diffusion layer of the MEA consisted of hydrophilic region and hydrophobic region (with a ratio of region areas of 1:1). The electrochemical impedance spectra analyses revealed that the mass transfer resistance of novel MEA was lower than that of completed hydrophilic or hydrophobic MEA. The performance of novel MEA for DDFC was enhanced due to the promotion the mass transport of DME fuel at 50 °C. The constant current operation curves showed that the performance decay ratio of the novel MEA was lower than that of conventional MEAs. It indicated that the novel MEA benefited the long-term operation of DDFC.     

A highly efficient procedure for the oxathioacetalization of carbonyl compounds under solvent-free conditions

The novel efficient procedure has been developed for the oxathioacetalization of carbonyl compounds and 2-mercaptoethanol using the novel carbon-based sulfonic acid as catalyst under solvent-free condition at room temperature. The results showed that the novel catalyst was very efficient for the reactions with good to excellent yields in short time. The novel catalyst owned many advantages such as operational simplicity, without need of any solvent, small amount of usage, low cost of the catalyst used, high yields, applicability to large-scale reactions, reusability and chemoselectivity over the traditional catalysts, which made the catalyst one of the best choices for the reactions.     

Novel oxybispyridylboronic acids: synthesis and study of their reactivity in Suzuki-type cross-coupling reactions

This paper sets forth the synthesis of novel oxybispyridylboronic acids, which are prepared from the corresponding halo-oxybispyridines via halogen-metal exchange using n-butyllithium and treatment with triisopropylborate. A range of efficient cross-coupling reactions of these novel boronic acids with selected aryl halides is described. This strategy produces novel pyridylethers of interest in cholinergic medicinal chemistry.