离子负载的双(三氟乙酰氧基)碘苯对乙酰苯胺类化合物的乙酰氧基化反应

制备了1种新的含有酰胺键的离子负载的双(三氟乙酰氧基)碘苯固体试剂--1-甲基-3-[4鄄(双三氟乙酰氧基碘)苯甲酰胺基乙基]咪唑四氟硼酸盐. 该试剂无吸湿性, 在空气中长期放置不变质. 研究了1种离子负载的二(乙酰氧基)碘苯试剂和3种离子负载的双(三氟乙酰氧基)碘苯试剂对乙酰苯胺的对位乙酰氧基化反应. 结果表明, 离子负载的二(乙酰氧基)碘苯试剂氧化能力较弱, 乙酰氧基化产物产率较低; 含有酰胺键的2种离子负载的双(三氟乙酰氧基)碘苯试剂不发生乙酰氧基化反应; 而1-甲基-3-[4-双(三氟乙酰氧基)碘苯甲基]咪唑四氟硼酸盐是理想的氧化剂. 以1-甲基-3-[4-双(三氟乙酰氧基)碘苯甲基]咪唑四氟硼酸盐为氧化剂, 室温下乙酰苯胺及其衍生物与乙酸可区域选择性地发生乙酰氧基化反应, 产率较高. 回收后的离子负载的碘苯容易再生成试剂, 而再生试剂的乙酰氧基化反应活性几乎保持不变.     

叔丁基过氧化氢和碘介导的烯基化二羰基化合物的碘环化合成5-碘甲基二氢呋喃

发展了一种通过烯基化二羰基化合物的碘环化合成多取代5-碘甲基二氢呋喃的新方法,该方法以过氧化叔丁醇(TBHP)和I₂原位形成的次碘酸和^tBu OI为活性碘正离子试剂.本反应具有反应条件温和、碘原子利用率高、试剂廉价易得等优点.     

Pd/SiC催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应性能

以高比表面积碳化硅为载体,通过液相还原法制备出Pd/SiC催化剂,并用于催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应.利用X射线衍射、电感耦合等离子体质谱和高分辨透射电子显微镜等对催化剂进行了表征.结果表明, SiC表面的Pd纳米颗粒分散均匀,平均粒径约为2.8 nm.在优化溶剂、碱、压力和温度等反应条件后,发现以3 mmol的K2CO3和10 mL苯甲醚分别为碱和溶剂,1.0 mmol碘苯和1.5 mmol苯硼酸在3 wt% Pd/SiC催化剂存在的条件下,在CO压力为1.0 MPa和100oC下反应8 h即可实现羰化偶联,碘苯转化率为90%,二苯甲酮选择性为99%.并且, Pd/SiC对含有不同官能团的碘代芳烃和芳基硼酸羰化Suzuki偶联反应具有较好的普适性.同时, Pd/SiC也具有较好的稳定性,经5次循环反应后,碘苯转化率从90%降至76%;催化剂活性降低的主要原因是活性组分Pd在有机反应体系中的流失.     

Pd/SiC催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应性能

以高比表面积碳化硅为载体,通过液相还原法制备出Pd/SiC催化剂,并用于催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应.利用X射线衍射、电感耦合等离子体质谱和高分辨透射电子显微镜等对催化剂进行了表征.结果表明, SiC表面的Pd纳米颗粒分散均匀,平均粒径约为2.8 nm.在优化溶剂、碱、压力和温度等反应条件后,发现以3 mmol的K2CO3和10 mL苯甲醚分别为碱和溶剂,1.0 mmol碘苯和1.5 mmol苯硼酸在3 wt% Pd/SiC催化剂存在的条件下,在CO压力为1.0 MPa和100oC下反应8 h即可实现羰化偶联,碘苯转化率为90%,二苯甲酮选择性为99%.并且, Pd/SiC对含有不同官能团的碘代芳烃和芳基硼酸羰化Suzuki偶联反应具有较好的普适性.同时, Pd/SiC也具有较好的稳定性,经5次循环反应后,碘苯转化率从90%降至76%;催化剂活性降低的主要原因是活性组分Pd在有机反应体系中的流失.     

以ZnAl-XO_3~-LDHs/Li X(X=Br,I)为卤源高效合成烯烃的二溴化物以及碘乙酸酯类产物（英文）

在温和的反应条件下,使用ZnAl-XO_3~--LDHs (X=Br, I)为氧化剂和相应的金属卤化物LiX为还原剂,实现烯烃的二溴化及碘乙酰氧基化反应,合成一系列二溴烷烃和碘乙酸酯类产物.分析结果表明,该方法产率较高,二溴烷烃类为74%~94%,碘乙酸酯类为75%~93%,该反应具有高区域选择性和立体选择性.     

碘叶立德的化学反应研究进展

自首个有关叶立德的反应被报道以来,它们就成为有机化学中的一个重要研究方向.其中碘叶立德因兼具碘化合物和叶立德的独特反应性受到了人们的广泛关注.先概括性地阐述了碘叶立德的制备方法和结构性质,然后对其在有机合成中的应用做了详细的描述,包括碘叶立德作为有效的卡宾前体在插入反应、环丙烷化反应中的应用及其在环加成反应、重排反应和...     

乙醛和不饱和三氟甲基酮不对称Aldol反应合成光学活性的β-三氟甲基-β-羟基-δ-戊内酯

以手性伯胺为催化剂催化共轭不饱和三氟甲基酮与乙醛的不对称反应为关键步骤,合成了光学活性的β-三氟甲基?-β-羟基-δ-戊内酯.合成过程中包含乙醛和共轭不饱和三氟甲基酮的不对称Aldol反应、氧化反应、碘内酯化以及脱碘反应.     

选择性碘内酯化反应的研究进展

碘内酯化反应是通过含碘试剂与烯酸化合物进行反应生成碘代内酯，该反应具 有较强的区域和立体选择性，在不对称有机合成中起重要作用，主要综述近年来碘 内酯化反应的区域选择性控制和立体选择性控制（包括非对映选择性和对映选择性 控制）及其在不对称合成应用中的进展。     

Pd/SiC催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应性能（英文）

以高比表面积碳化硅为载体,通过液相还原法制备出Pd/Si C催化剂,并用于催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应.利用X射线衍射、电感耦合等离子体质谱和高分辨透射电子显微镜等对催化剂进行了表征.结果表明,Si C表面的Pd纳米颗粒分散均匀,平均粒径约为2.8 nm.在优化溶剂、碱、压力和温度等反应条件后,发现以3 mmol的K2CO3和10 m L苯甲醚分别为碱和溶剂,1.0 mmol碘苯和1.5 mmol苯硼酸在3 wt%Pd/Si C催化剂存在的条件下,在CO压力为1.0 MPa和100 oC下反应8 h即可实现羰化偶联,碘苯转化率为90%,二苯甲酮选择性为99%.并且,Pd/Si C对含有不同官能团的碘代芳烃和芳基硼酸羰化Suzuki偶联反应具有较好的普适性.同时,Pd/Si C也具有较好的稳定性,经5次循环反应后,碘苯转化率从90%降至76%;催化剂活性降低的主要原因是活性组分Pd在有机反应体系中的流失.     

基于C-H键活化的铜催化二苄胺氧化酰胺化反应

基于铜催化的C-H键活化构建了一类高效的二苄胺氧化酰基化生成N-苄基苯甲酰胺的反应. 该反应使用CuBr作为催化剂, 二乙酸碘苯作为氧化剂, 在温和条件下生成两种酰胺, 总产率最高可达92.0%. CuBr催化剂价廉易得, 催化活性高. 同时这也是首次使用二乙酸碘苯作为氧化剂, 通过二苄胺的直接氧化酰基化反应合成N-苄基苯甲酰胺.     

Contributions to the Chemistry of the Binary Compounds of the Transition Elements

Phase and structural relationships of the sulfur, selenium, and tellurium compounds of the 4d and 5d transition elements of groups IV to VII of the periodic system are discussed. Homologous elements behave very similarly with respect to the chalcogens, and this is particularly the case for niobium and tantalum, and for molybdenum and tungsten. However, zirconium, niobium, and molybdenum have a greater tendency towards formation of chalcogen-poor phases than their homologues hafnium, tantalum, and tungsten. Subchalcogenides are known only for zirconium and niobium. The number of phases and the tendency towards formation of solid solutions are considerably smaller among the tellurides than among the sulfides and selenides. The crystal structures of the telluride phases also differ from those of the sulfide and selenide phases of analogous composition. In addition, a review of the phase and structural relationships of the arsenic and antimony compounds of the 4d and 5d transition elements of groups V to VII is given.     

天然化合物芦丁的治疗潜力

芦丁属于类黄酮化合物,广泛存在于人们日常食用的各种蔬菜、水果和中草药中。 芦丁是天然的抗氧化剂,有清除自由基的特性,可调节众多疾病有关的细胞内和细胞外信号通路,影响细胞的生长,分化及其功能,对人们的健康,防病治病起着重要作用。芦丁具有广泛的药理活性,抗氧化、抗炎、抗病毒、抗癌、预防和治疗心脑血管疾病。以芦丁为原料的药品有多种,使用芦丁毒副作用小,安全,成本低。由于芦丁的生物利用度低,在临床上应用受到一定的限制。克服芦丁溶解性差的问题已经有各种方法,例如使用环糊精的络合,磷脂等,改善水溶性,从而增加生物利用度。本文综述了芦丁的多种潜在用途和治疗作用的信息,与药物输送相关的问题,以及改善药物生物利用度的可能方法。重点介绍了芦丁的抗炎、抗癌、降糖、对心血管的保护作用,为天然化合物的开发和利用奠定基础。     

Recent developments in capillary and microchip electroseparations of peptides (2017–mid 2019)

The review presents a comprehensive survey of recent developments and applications of high performance capillary and microchip electroseparation methods (zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography) for analysis, micropreparation, and physicochemical and biochemical characterization of peptides since 2017 up to about the middle of 2019. Progress in the study of electromigration properties of peptides and in the methodology of their analysis (sample preseparation, preconcentration and derivatization, adsorption suppression, EOF control, and detection) are described. Advances in CE and CEC methods are demonstrated and their applications in the following areas are presented: qualitative and quantitative analysis, determination in complex (bio)matrices, monitoring of chemical and enzymatical reactions and physical changes, amino acid, sequence and chiral analysis, and peptide mapping of proteins. In addition, micropreparative separations and determinations of important physicochemical characteristics of peptides by CE and CEC methods are reported.     

Nutraceutical Role of Polyphenols and Triterpenes Present in the Extracts of Fruits and Leaves of Olea europaea as Antioxidants,Anti-Infectives and Anticancer Agents on Healthy Growth

There is currently a worldwide consensus and recognition of the undoubted health benefits of the so-called Mediterranean diet, with its intake being associated with a lower risk of mortality. The most important characteristics of this type of diet are based on the consumption of significant amounts of fruit, vegetables, legumes, and nuts, which provide, in addition to some active ingredients, fiber and a proportion of vegetable protein, together with extra virgin olive oil (EVOO) as the main sources of vegetable fat. Fish and meat from poultry and other small farm animals are the main sources of protein. One of the main components, as already mentioned, is EVOO, which is rich in monounsaturated fatty acids and to a lesser extent in polyunsaturated fatty acids. The intake of this type of nutrient also provides an important set of phytochemicals whose health potential is widely spread and agreed upon. These phytochemicals include significant amounts of anthocyanins, stilbenes, flavonoids, phenolic acids, and terpenes of varying complexities. Therefore, the inclusion in the diet of this type of molecules, with a proven healthy effect, provides an unquestionable preventive and/or curative activity on an important group of pathologies related to cardiovascular, infectious, and cancerous diseases, as well as those related to the metabolic syndrome. The aim of this review is therefore to shed light on the nutraceutical role of two of the main phytochemicals present in Olea europaea fruit and leaf extracts, polyphenols, and triterpenes, on healthy animal growth. Their immunomodulatory, anti-infective, antioxidant, anti-aging, and anti-carcinogenic capabilities show them to be potential nutraceuticals, providing healthy growth.     

Semiconductor quantum dots and metal nanoparticles: syntheses,optical properties,and biological applications

We review the syntheses, optical properties, and biological applications of cadmium selenide (CdSe) and cadmium selenide–zinc sulfide (CdSe–ZnS) quantum dots (QDs) and gold (Au) and silver (Ag) nanoparticles (NPs). Specifically, we selected the syntheses of QDs and Au and Ag NPs in aqueous and organic phases, size- and shape-dependent photoluminescence (PL) of QDs and plasmon of metal NPs, and their bioimaging applications. The PL properties of QDs are discussed with reference to their band gap structure and various electronic transitions, relations of PL and photoactivated PL with surface defects, and blinking of single QDs. Optical properties of Ag and Au NPs are discussed with reference to their size- and shape-dependent surface plasmon bands, electron dynamics and relaxation, and surface-enhanced Raman scattering (SERS). The bioimaging applications are discussed with reference to in vitro and in vivo imaging of live cells, and in vivo imaging of cancers, tumor vasculature, and lymph nodes. Other aspects of the review are in vivo deep tissue imaging, multiphoton excitation, NIR fluorescence and SERS imaging, and toxic effects of NPs and their clearance from the body. Figure Semiconductor quantum dots and metal nanoparticles have extensive applications, e.g., in vitro and in vivo bioimaging Tamitake Itoh and Abdulaziz Anas contributed equally to this article.     

Antihypertensive activity of indole and indazole analogues: A review

Heterocyclic compounds occupy an important position in chemistry because of their wide range of uses in drug design, photochemistry, agrochemicals, and other fields. Indole and indazole scaffolds are available from natural and synthetic sources, and molecules containing these scaffolds have been shown to have various biological effects, including anti-inflammatory, antibacterial, antiviral, antifungal, analgesic, anticancer, antioxidant, anticonvulsant, antidepressant, and antihypertensive activities. Indole and indazole molecules bind to receptors with high affinity, and thus are useful for the study of bioactive compounds involved in multiple pathways. In this review, we highlight the antihypertensive activity and the mechanisms of action of indole and indazole derivatives. In addition, structure–activity relationship studies of the antihypertensive effect are presented.     

Tools and resources for metabolomics research community: A 2017–2018 update

The scale at which MS‐ and NMR‐based platforms generate metabolomics datasets for both research, core, and clinical facilities to address challenges in the various sciences—ranging from biomedical to agricultural—is underappreciated. Thus, metabolomics efforts spanning microbe, environment, plant, animal, and human systems have led to continual and concomitant growth of in silico resources for analysis and interpretation of these datasets. These software tools, resources, and databases drive the field forward to help keep pace with the amount of data being generated and the sophisticated and diverse analytical platforms that are being used to generate these metabolomics datasets. To address challenges in data preprocessing, metabolite annotation, statistical interrogation, visualization, interpretation, and integration, the metabolomics and informatics research community comes up with hundreds of tools every year. The purpose of the present review is to provide a brief and useful summary of more than 95 metabolomics tools, software, and databases that were either developed or significantly improved during 2017–2018. We hope to see this review help readers, developers, and researchers to obtain informed access to these thorough lists of resources for further improvisation, implementation, and application in due course of time.     

Self-Assembling Drug Formulations with Tunable Permeability and Biodegradability

This review focuses on key topics in the field of drug delivery related to the design of nanocarriers answering the biomedicine criteria, including biocompatibility, biodegradability, low toxicity, and the ability to overcome biological barriers. For these reasons, much attention is paid to the amphiphile-based carriers composed of natural building blocks, lipids, and their structural analogues and synthetic surfactants that are capable of self-assembly with the formation of a variety of supramolecular aggregates. The latter are dynamic structures that can be used as nanocontainers for hydrophobic drugs to increase their solubility and bioavailability. In this section, biodegradable cationic surfactants bearing cleavable fragments are discussed, with ester- and carbamate-containing analogs, as well as amino acid derivatives received special attention. Drug delivery through the biological barriers is a challenging task, which is highlighted by the example of transdermal method of drug administration. In this paper, nonionic surfactants are primarily discussed, including their application for the fabrication of nanocarriers, their surfactant-skin interactions, the mechanisms of modulating their permeability, and the factors controlling drug encapsulation, release, and targeted delivery. Different types of nanocarriers are covered, including niosomes, transfersomes, invasomes and chitosomes, with their morphological specificity, beneficial characteristics and limitations discussed.     

Indole-Containing Natural Products 2019–2022: Isolations,Reappraisals, Syntheses,and Biological Activities

Indole alkaloids represent a large subset of natural products, with more than 4100 known compounds. The majority of these alkaloids are biologically active, with some exhibiting excellent antitumor, antibacterial, antiviral, antifungal, and antiplasmodial activities. Consequently, the natural products of this class have attracted considerable attention as potential leads for novel therapeutics and are routinely isolated, characterized, and profiled to gauge their biological potential. However, data on indole alkaloids, their various structures, and bioactivities are complex due to their diverse sources, such as plants, fungi, bacteria, sponges, tunicates, and bryozoans; thus, isolation methods produce an incredible trove of information. The situation is exacerbated when synthetic derivatives, as well as their structures, bioactivities, and synthetic schemes, are considered. Thus, to make such data comprehensive and inform researchers about the current field’s state, this review summarizes recent reports on novel indole alkaloids. It deals with the isolation and characterization of 250 novel indole alkaloids, a reappraisal of previously reported compounds, and total syntheses of indole alkaloids. In addition, several syntheses and semi-syntheses of indole-containing derivatives and their bioactivities are reported between January 2019 and July 2022.