3-(3＇-乙酰基-5＇-芳基-1＇,3＇,4＇-二氢噁二唑-2＇-)色酮的微波促进合成

杂环取代色酮;3-(3＇-乙酰基-5＇-芳基-1＇;3＇;4＇-二氢噁二唑-2＇-)色酮的微波促进合成     

N-取代吡唑亚甲胺基-N＇-取代苯基(硫)脲的合成

硫脲;生物活性;N-取代吡唑亚甲胺基-N＇-取代苯基(硫)脲的合成     

4′-取代苯并-15-冠-5-苦味酸分子络合物的核磁共振研究

研究了15种4＇-取代苯并-15-冠-5及其与苦味酸所形成的电荷转移络合物的~1H NMR,测定了其中12种络合物的络合常数。络合常数、参考线REL～[D]的斜率以及络合前后4＇-取代苯并-15-冠-5各类质子与笨并-15-冠-5相应的质子化学位移之差△σ均与Hammett取代基常数[σ_p σ_m]呈线性关系。根据取代基对各类质子化学位移变化的影响,讨论了有关化合物的结构与性能的关系。     

取代吲哚-3-甲酸类化合物的合成

吲哚-3-甲酸是一种重要的有机中间体,被广泛应用于医药与农药的合成.以取代邻硝基甲苯为原料,与N,N-二甲基甲酰胺二甲基缩醛(DMFDMA)反应制得取代2-硝基-β-二甲氨基苯乙烯,再经铁粉和冰乙酸还原环合生成取代吲哚,取代吲哚与三氟乙酸酐经酰化、碱性条件下水解制得5种取代吲哚-3-甲酸类化合物,该合成方法操作简单,条件温和,收率较高.     

1-烃基-5-取代氨基-4-吡唑(N-取代)甲酰胺的合成及生物活性研究

本文采用吡唑并[3,4-d]-1,3-噁嗪-6-酮衍生物(Ⅰ)与伯胺反应,合成了1-烃基-5-取代苯甲酰胺基-4-吡唑(N-取代)甲酰胺(Ⅱ);由LiAlH,对Ⅱ分子中2个酰胺基的选择性还原合成了1-烃基-5-取代氨基-4-吡唑(N-取代)甲酰胺(Ⅲ).共合成新化合物23个,通过~1H NMR、~(13)CNMR、MS、IR等证明了它们的化学结构,初步生物活性测定表明化合物Ⅱ具有一定的抗癌活性和农药活性。     

新型5-取代吲哚-3-甲酰胺化合物的合成

以5-取代吲哚为原料,经维尔斯迈尔-哈克反应制得5-取代吲哚-3-甲醛(2a~2e);2a~2e在DMF催化下,与盐酸羟胺反应制得5-取代吲哚-3-甲腈(3a~3e);3a~3e在H2O2和Na OH溶液中水解合成了5-取代吲哚-3-甲酰胺(4a~4e,4b~4e为新化合物),产率62.0%~75.0%,其结构经1H NMR,13C NMR和ESI-MS表征。     

N-取代苯基-2-取代-1,3-噻唑烷-3-甲酰胺的合成、结构及生物活性

为了寻找新的含噻唑杂环的先导化合物, 利用2-取代-1,3-噻唑烷与取代苯基异氰酸酯在三乙胺催化下发生偶合反应, 合成了17个N-取代苯基-2-取代-1,3-噻唑烷-3-甲酰胺化合物3, 并利用¹H NMR, IR, MS和元素分析对其结构进行了表征. 用X-ray单晶衍射测定了N-苯基-2-氧代-1,3-噻唑烷-3-甲酰胺(3a)的晶体结构. 初步生物活性试验结果表明, 在试验浓度下部分目标化合物具有一定的杀菌和杀虫活性.     

3-取代苄氧基-6-取代氨基哒嗪衍生物的合成及其除草活性

通过3-取代苄氧基-6-氟哒嗪在75～80 ℃与二甲胺的绝对无水乙醇溶液封管反应, 或在回流条件下分别与吗啡啉或哌啶反应, 合成一系列新颖的3-取代苄氧基-6-取代氨基哒嗪类化合物, 它们的结构均经IR, ¹H NMR和元素分析确证. 初步的除草活性测定结果表明, 该类化合物具有一定的除草活性, 讨论了它们的结构与除草活性的关系.     

BTC/DMF辅助的1-取代苯基-3,4-二取代吡唑类衍生物的合成

室温条件下,以各种取代苯肼和环状酮为起始原料,经脱水成腙和Vilsmeier试剂(BTC/DMF)环合两步反应合成了1-取代苯基-3,4---取代吡唑类衍生物(4a～4i),其结构经1H NMR,13C NMR,IR和MS表征,其中4b,4c,4e,4f和4h为新化合物.     

聚8,8＇-二羟基-5,5＇-偶氮苯二喹啉金属螯合物的合成及荧光性质

羟基喹啉;自组装薄膜;聚8;8＇-二羟基-5;5＇-偶氮苯二喹啉金属螯合物的合成及荧光性质     

Borohydride Ionic Liquids as Hypergolic Fuels: A Quest for Improved Stability

Hydrazine and its derivatives are used as fuels in rocket propellant systems; however, due to high vapor pressure, toxicity, and carcinogenicity, handling of such compounds is extremely hazardous. Hypergolic ionic liquids have shown great promise to become viable replacements for hydrazines as fuels. Borohydride‐containing ionic liquids have now been synthesized using a more efficient synthetic pathway that does not require liquid ammonia and halide precursors. Among the eight new compounds, 1‐allyl‐3‐n‐butyl‐imidazolium borohydride ( 1 ) and 1, 3‐diallylimidazolium borohydride ( 5 ) exhibit very short ignition‐delay times (ID) of 8 and 3 ms, respectively. The hydrolytic stability of borohydride compounds has been greatly improved by attaching long‐chain alkyl substituents to the imidazole ring. 1,3‐Di‐(n‐octyl)‐imidazolium borohydride ( 3 ) is a water stable borohydride‐containing ionic liquid. 1,3‐Di‐(n‐butyl)‐imidazolium borohydride ( 2 ) is a unique example of a borohydride liquid crystal. These ionic liquids have some unusual advantages, including negligible vapor pressures, good ignition delay (ID) times, and reduced synthetic and storage costs, thereby showing good application potential as environmentally friendly fuels in bipropellant formulations. In addition, they also have potential applications in the form of reducing agents and hydrogen storage materials.     

Electrochemical Behavior of Gold Nanoparticles Generated In Situ on 3‐(1‐Imidazolyl)propyl‐silsesquioxane

Gold nanoparticles of different morphologies have been synthesized on a silica‐based organic‐inorganic hybrid material for catalytic applications. The gold nanoparticles formations proceed through in situ chemical reduction of the AuCl₄^? anions previously adsorbed on 3‐(1‐imidazolyl)propyl‐silsesquioxane, which plays the role of substrate and stabilizer. Two distinct reducing agents, sodium citrate and sodium borohydride, were employed to generate gold nanoparticles of different sizes. UV‐vis diffuse reflectance as well as transmission electron microscopy were employed to evaluate the particle’s morphology. Modified carbon paste electrodes were prepared from these materials and their electrochemical behavior investigated using potassium ferrocyanide and 4‐nitrophenol as redox model compounds. Both AuNPs‐modified electrodes decreased the overpotential of 4‐nitrophenol reduction by around 90 mV compared to the unmodified electrode as evidenced by cyclic voltammetry experiment. However, the smaller diameter particles (borohydride‐reduced) produced more significant catalytic effect as a consequence of their large surface area. Regarding the sensing parameters, the sensitivity is higher for the borohydride‐reduced AuNPs while the values of limit of detection are of the same order of magnitude. Thus, the detection limit and sensitivity are 70.0±0.6 nM and 187 µA/mM for the citrate‐reduced AuNPs; and 75.0±2.2 nM and 238 µA/mM for the borohydride‐reduced AuNPs.     

Poly(1,4-butyl-bis-vinylpyridinium) borohydride as a new stable and efficient reducing agent in organic synthesis

The unstable sodium borohydride is stabilized on modified poly(4-vinylpyridinium), and it is used as an efficient and regenerable polymer-supported borohydride reagent for the reduction of a variety of carbonyl compounds, such as aldehydes, ketones, α,β-unsaturated carbonyl compounds, α-diketones and acyloins, in good to excellent yields.     

New copper-containing catalysts based on modified amorphous silica and their use in flow azide—alkyne cycloaddition

Сopper-containing catalysts supported on amorphous silica modified by amines were prepared using the chemical reduction method. The morphology of copper particles and their chemi calstate depend on the type of the reducing agent used. The use of ascorbic acid results in the formation of monodisperse submicron Cu⁰ particles 200—300 nm in size, whereas Cu⁰ particles with a size ranging from 50 to 150 nm are formed when hydrazine hydrate was used. The morphology and chemical state of the copper particles reduced with sodium borohydride depend substantially on the amount of the reducing agent: Cu⁰ nanoparticles 10—15 nm in size are formed if the reducing agent is an excess, layered Cu₂O plates are formed at the equimolar amount of sodium borohydride, and a decrease in the amount of sodium borohydride results in spherical Cu₂O particles. All the catalysts synthesized in the flow regime showed higher activity in the catalytic cycloaddition of azides to alkynes than the commercially available copper catalysts.     

Poly-n-(Pyrazine)Zinc Borohydride as a New Stable,Efficient and Selective Reducing Agent

Coordination polymer of unstable zinc borohydride and pyrazine is prepared and used as an stable, efficient and selective bench top reducing agent for a variety of organic compounds.     

Tea polyphenol-assisted green synthesis of Ag-nanodiamond hybrid and its catalytic activity towards 4-nitrophenol reduction

Herein, we describe an environmentally friendly strategy to synthesize Ag nanoparticles on Nanodiamond (ND) by utilizing natural adhering and reduction properties of tea polyphenols (TPs). Firstly, the surface of ND was modified by TPs through their natural adhering ability. Then, the modified TPs functioned as reducing agents for reducing Ag precursor in situ. The synthesis process, structure and its physicochemical properties of the nanohybrid were tracked and characterized by UV-Vis, FTIR, TGA, HRTEM, XRD and XPS. It has been shown that Ag nanoparticles with uniform size and distribution were anchored successfully on the surface of ND. The ND supported Ag nanoparticles displayed highly water dispersibility due to the hydrophilicity of TPs, as is very important in heterogeneous catalysis. The catalytic performance of this nanohybrid was evaluated comprehensively by catalyzing 4-nitrophenol reduction by sodium borohydride, which is often used as a model reaction, showing excellent catalytic activity and recycling stability.     

A new synthesis of n-blocked dihydrouracil and dihydroorotic acid derivatives using lithium tri-sec-butyl borohydride as reducing agent

1,3-Di-N-substituted uracil and its derivatives have been reduced with lithium-tri-$\text{sec}$-butyl borohydride to the corresponding 5,6-dihydro compounds in excellent yields. Alkylation of 5-position of uracil is also very conveniently accomplished.     

Solid Phase Derivatizations in HPLC: Borohydride/Silica Reductions for Carbonyl Compounds

Abstract

Sodium borohydride adsorbed onto silica gel has now been utilized for on-line, pre-and post-analytical column chemical derivatizations via reductions of various organic carbonyl compounds. These on-line reactions have been performed using normal phase HPLC conditions, involving conventional silica gel packings, organic mobile phases, and commercially available HPLC equipment and instrumentation. This approach for on-line HPLC derivatizations has been evaluated for a large number of organic carbonyl compounds, at a variety of temperatures for aldehydes and ketones. The overall rates of such carbonyl reductions via sodium borohydride/silica are sufficiently different as a function of temperature of the reaction to permit for compound/class identifications. Analyte identification can be both qualitative and quantitative, even wherein an analyte co-elutes with a non-carbonyl compound. In-house prepared borohydride/silica gel reactors can be characterized via standard iodine titration procedures along with inductively coupled plasma (ICP) elemental boron analysis. These normal phase derivatization approaches have been applied to certain standard vitamins, and to cinnamaldehyde found in a commercial spice product. Such approaches to on-line HPLC derivatizations     

Synthesis of gold–polyaniline nanocomposites by complexation

Complexation synthesis methods have been examined in the preparation of nanogold–polyaniline systems. This extends work previously reported on the use of a spontaneous redox coupling of aniline polymerization to the reduction of a gold salt added to the monomer and mixed initially at the molecular level. The extension involves the addition of an additional reducing agent in the form of borohydride. The end product of the nanoparticle Au–PANI composite is very much a function of the borohydride : Au and N : Au ratios used in the synthesis. The size of the resulting gold particles can be directly tuned in the diameter range 2–10 nm by adjusting the borohydride : Au ratio used. Thorough characterization of the structures of the composites has been undertaken. Copyright © 2016 John Wiley & Sons, Ltd.     

Microdetermination of carbonyl compounds by reduction with alkaline sodium borohydride

Summary Alkaline sodium borohydride has been employed as a reducing reagent for the titrimetric determination of compounds containing the carbonyl function. The sample is dissolved in methanol and is then reduced with alkaline sodium borohydride. After completion of the reaction, the excess sodium borohydride is back titrated against standardized hydrochloric acid solution using methyl red as indicator. The stoichiometry between the carbonyl function and sodium borohydride is 41.

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Zusammenfassung Natriumborhydrid dient als Reduktionsmittel zur Titration von Carbonylverbindungen. Die Probe wird in Methanol gelöst und dann mit alkalischem Natriumborhydrid reduziert. Nach Ablauf der Reaktion wird der Überschuß mit Salzsäure gegen Methylrot zurücktitriert. Carbonylverbindung und Natriumborhydrid reagieren im Verhältnis 41.