Reduction of 3‐Acyl Derivatives of Oxindoles,Benzo[b]furan‐2‐ones,and Benzo[b]thiophen‐2‐ones to the Corresponding Alkyl Derivatives by Sodium Borohydride–Acetic Acid

It was found that 3‐acyl derivatives of oxindoles, benzo[b]furan‐2‐ones, and benzo[b]thiophen‐2‐ones could be efficiently and conveniently reduced to the corresponding alkyl derivatives by pelletized sodium borohydride in acetic acid. A typical procedure involves heating the acylated substrates for approximately 90 min in a slurry of glacial acetic acid and sodium borohydride to provide the 3‐alkyl product in yields ranging from 62% to 96%. This synthetic methodology represents a convenient approach to the synthesis of the alkyl derivatives.     

1,4-Diazabicyclo[2.2.2]octane as an Efficient Catalyst for a Clean,One-Pot Synthesis of Tetrahydrobenzo[b]pyran Derivatives via Multicomponent Reaction in Aqueous Media

1,4-Diazabicyclo[2.2.2]octane (DABCO) has been used as a mild and efficient catalyst for the synthesis of various tetrahydrobenzo[b]pyran derivatives via a one-pot, three component condensation of aromatic aldehydes, dimedone, and active methylene compounds. This method provides several advantages: a simple workup procedure, environmental friendliness, neutral conditions, and good yields. In addition, water or 50% aqueous ethanol was chosen as a green solvent.

Stereoselective Synthesis of 1,3-Dienes from Propargylic Alcohols by LiAlH4/AlCl3

Herein we report that LiAlH₄/AlCl₃ is a very efficient reagent for the reductive dehydration of aryl propargylic alcohols in tetrahydrofuran solvent at reflux to give 1,3-dienes with good yields and high E selection. The reaction conditions are mild and easy to operate, and a variety of aryl functional groups, such as bromo, fluoro, butyl, and methoxyl groups, are tolerated. With our protocol, useful (E,E)-1,3-dienes can be synthesized.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

[Co（H2o）4（NCS）2]（18—C—6）的薄层光谱电化学研究

利用光谱电化学方法来研究冠醚类化合物的文章尚未见报导.本文在测定用凝胶法合成的[Co(H_2O)(NCS)_2](18-C-6)的核磁共振谱和红外光谱的基础上,使用循环伏安法和薄层光谱电化学技术,在金微栅电极上测定了此配合物在乙腈溶剂中的第一步克式量电势(E~0′)和电子转移数(n),并推测了电还原反应机理.     

含铜MFI分子筛的H2-TPT和O2-TPD研究

 采用H2－TPR和O2－TPD手段考察了不同金属离子交换的ZSM－5分子筛催化剂上的氢还原性能和氧脱附性能．发现Cu－ZSM－5催化剂的储氧能力及氧脱附性能优于Co－ZSM－5和Fe－ZSM－5催化剂;储氧能力强、低温下氧脱附性能好的催化剂,对NO分解反应的催化活性就高．铜离子是反应的活性中心．添加Ag和Ce可使Cu－ZSM－5催化剂上氧的脱附温度大大降低．Cu－ZSM－5／堇青石整体式催化剂上Cu的存在形式与单纯的Cu－ZSM－5有差异,整体式催化剂上的一价铜数量少,但较稳定．     

在线性或交联的聚氨酯粒子内原位还原制备纳米银粒子

纳米金属粒子有特异性质 ,可用作高效催化剂、非线性光学材料等 .为防止其聚集 ,不少研究者采用表面活性剂 [1]、配位体 [2 ]和高分子等以阻止纳米金属粒子的聚集 .近年来高分子金属复合纳米粒子引起人们广泛的兴趣 [3～ 9] .文献上大多采用线性或嵌段双亲高分子作纳米金属的分散稳定剂[6 ] 或在高分子粒子表面沉积纳米金属粒子[5] ,也有人采用多孔交联高分子微球的孔洞作为微反应器形成纳米金属粒子[7] .这些方法均不能有效地控制金属粒子的粒径 ,特别难以合成粒径小于 3 0 nm的银粒子 .本文首次报道了在常温处于粘弹态 ,线性或交联的高分…     

HA型大孔吸附树脂及活性炭对胆红素吸附性能的研究

本文选用HA型大孔吸附剂对患者血中胆红素进行了动态、静态吸附性能实验,考察了其对血液生化的影响。同时,用瑞典GAMBRO肾罐中活性炭进行了比较,实验结果表明,HA吸附剂对直接胆红素的吸附功效与进口活性基本相同,但血液生化指标HA吸附剂优于活性炭。     

Heterometallic zirconocene(iii) aluminum hydride complex (Cp2ZrH)2HAlCl2·C4H8O2·C6H6

The heterometallic zirconocene(iii) aluminum hydride complex (Cp₂ZrH)₂HAlCl₂·C₄H₈O₂·C₆H₆ was synthesized by reduction of Cp₂ZrCl₂ with lithium aluminum hydride in the presence of Cp₂TiBH₄ and 1,4-dioxane, and its structure was established by X-ray diffraction analysis.     

Selective reduction of the acyl group in cyclic α-acyl-β-dicarbonyl compounds with sodium cyanoborohydride. Efficient synthesis of cyclic α-alkyl-β-dicarbonyl compounds

Efficient synthesis of cyclic -alkyl--dicarbonyl compounds of the cyclopentane, cyclohexane, tetronic acid, and -pyrone series from the corresponding cyclic -acyl--dicarbonyl compounds under the action of NaBH₃(CN) in a THF--HCl system is described.     

苯乙酮氢转移反应中ZrO2/MCM-41和ZrO2/AC的催化性能对比

采用浸渍法制备了分别以活性炭(AC)和全硅MCM-41介孔分子筛负载的ZrO2催化剂,并对其进行了XRD、氮气吸附-脱附、X射线光电子能谱、差热-热重分析和吡啶吸附原位红外光谱等表征,考察了其在以异丙醇为氢源还原苯乙酮为α-苯乙醇的Meerwein-Ponndorf-Verley(MPV)反应中的催化活性,并与水合ZrO2进行对比.研究了载体对催化剂活性的影响.结果表明,ZrO2经MCM-41负载后,与载体发生强相互作用,可能形成Si—O—Zr键,ZrO2在载体表面呈高分散的无定形态,Zr—OH数目显著增加,L酸性增强,并形成B酸中心,使催化剂活性显著高于水合ZrO2;ZrO2负载在AC上后,与载体未发生强相互作用,ZrO2在载体表面未呈高分散状态,增加的Zr—OH数目相对较少,L酸性较弱,未形成B酸中心,催化活性未明显增加,但在较高焙烧温度(400～600℃)下,其仍能保持稳定的催化活性,这可归因于ZrO2/AC中AC孔道疏通及AC石墨层对苯乙酮上苯环的吸附作用,使活性位附近的反应底物浓度显著增大.