A Rapid and Convenient Synthesis of 1,1-Diacetates from Aldehydes and Acetic Anhydride Catalyzed by PVC-FeCl3 Catalyst

A variety of aldehydes can be converted into 1,1-diacetates rapidly and conveniently in the presence of catalytic amounts of poly(vinyl chloride) supported ferric chloride reagent at room temperature in excellent yields.     

乙酸促进邻甲基苯磺酸铜选择性催化醛与乙酸酐合成偕二乙酸酯反应

在室温无溶剂条件下,考察了乙酸促进邻甲基苯磺酸铜催化一系列芳香醛或脂肪醛与乙酸酐生成相应的偕二乙酸酯反应.结果表明,在乙酸存在条件下,邻甲基苯磺酸铜用量仅需占醛的0.3%(摩尔比)就能使反应在较短时间内完成.反应结束后,邻甲基苯磺酸铜经简单相分离可多次重复使用,催化活性无明显下降.     

Liquid-Phase Oxidation of Some Aromatic Aldehydes,Hydrocarbons, and Alcohols by Cerium(IV) Catalyzed by Iridium(III) in Acidic Medium

Addition of traces of iridium(III) chloride with cerium(IV) sulfate (catalyst–substrate ratio (1:2994 to 1:10,000) in traditional water-bath heating resulted in the oxidation of p-chlorobenzaldehyde, p-nitrobenzaldehyde, benzyl alcohol, p-methoxy benzyl alcohol, p-xylene, and p-nitrotoluene dissolved in acetic acid to give 77%, 90%, 21.7%, 88.6%, 86.2%, and 18% yields of the products, respectively, while catechol and resorcinol polymerized. Oxidation of aldehydes and alcohols resulted as usual in the corresponding acids and aldehydes, respectively, while p-xylene and p-nitrotoluene gave p-tolualdehyde and p-nitrobenzoic acid. Conditions were obtained for getting the highest yields under the experimental conditions.     

硅胶负载H6PMo9V3O40催化合成5-硝基水杨醛

采用硅胶负载Keggin型H6PMo9V3O40催化水杨醛与硝酸反应合成5-硝基水杨醛,考察了催化剂负载量、反应时间、反应温度、催化剂用量、硝酸用量和溶剂对反应的影响及催化剂的重复使用性能。实验结果表明,m(水杨醛)∶m(质量分数65%硝酸)∶m(负载量20%H6PMo9V3O40/SiO2)=2.44∶3.00∶3.00,用石油醚作为溶剂,45℃反应2.5 h,水杨醛的转化率为98%,5-硝基水杨醛的选择性为96.8%。催化剂回收容易,重复使用5次后,活性基本不变。     

利用氯化锌/微孔球状硅胶色谱柱制备α-叔丁基醛酮

在担载氯化锌的微孔球状硅胶色谱柱上,用溶有适宜配比的硅基烯醇醚/叔丁基氯的二氯甲烷溶液作流动相,再经二氯甲烷洗脱,水解等步骤处理后,可制得高收率的α-叔丁基醛酮化合物。     

PVP-PdCl2-CuCl2/SiO2-PEG600催化芳氯化物水相脱氯研究

PVP(聚乙烯吡咯烷酮)负载双金属催化剂催化芳香氯化物脱氯已有报道[1～3];利用双金属的协同作用,可以大大提高催化剂的脱氯活性和选择性[4]. 但是,这些研究多是在有机相中进行的,催化剂在水相中则会降低甚至失去活性,且难以回收和重复利用. 然而,难溶于水的有毒芳香氯化物,常存在于工业或生活排放的废水中. 由于治理环境的需要,研究芳香氯化物催化水相脱氯,则是极具挑战性的课题. 本文把起相转移作用的聚乙二醇(PEG)键合到硅胶上作为固相载体,制成双负载双金属水相脱氯催化剂PVP-PdCl2-CuCl2/SiO2-PEG600,成功地用于难溶于水的芳香氯化物的水相脱氯. 研究结果表明,这种催化剂对于芳香氯化物有良好的催化脱氯性能,使用中便于分离并能重复利用. 同时,用IR,TEM和XPS等手段对催化剂进行了表征,探讨了催化剂中各组分在催化脱氯中的作用.     

磺氨基醇手性配体的合成及钛配合物催化二乙基锌对醛的不对称加成反应

合成了手性磺氨基醇配体3～5, 将这些配体和Ti(O-i-Pr)₄应用于二乙基锌对醛的不对称加成反应, 获得了好的对映选择性, ee值最高为91%.     

Liquid Phase and Microwave Assisted Oxidation of Some Hydrocarbons,Aromatic Aldehydes,and Phenols by Cerium(IV) Catalyzed by Iridium(III) in Acidic Medium

Addition of traces of iridium(III) chloride with cerium(IV) sulphate (catalyst–substrate ratio 1:75757 to 1:151515) in traditional water-bath heating resulted in the oxidation of propyl benzene, naphthalene, dimethoxy benzaldehyde, trimethoxy benzaldehydes, cresol, and quinol dissolved in acetic acid to give 70, 33, 96, 74, 49, and 66% yields respectively of the products, while phenol and resorcinol polymerized. Reactants adsorbed on alumina under solventless conditions in a microwave oven resulted in the decrease in yield. Oxidation of both hydroxyl groups takes place in quinol, whereas it was selective at the α-carbon in the side chain and at the methyl group in the case of propyl benzene and cresol, respectively. Conditions were tested for the highest yields under the experimental conditions.     

Studies on the reaction of organotin phenoxides with ethyl propiolate catalysed by triethylamine and tin(IV) chloride

Different tributyltin phenoxides react at room temperature with ethyl propiolate in benzene, in the presence of tin(IV) chloride, triethylamine and their mixture to give the derivatives of 3‐phenoxyacrylic acid ethyl ester. Exceptionally, 3‐(2‐hydroxyphenyl)acrylic acid ethyl ester and 3‐(2‐hydroxy‐5‐methylphenyl)acrylic acid ethyl ester have been obtained from the reaction of tributylphenoxytin and tributyl(p‐tolyloxy)tin, respectively catalysed by SnCl₄, and they have been easily hydrolysed to coumarin and 6‐methylcoumarin. Copyright © 2007 John Wiley & Sons, Ltd.     

Efficient Synthesis of Symmetrical Bisamides from Aldehydes and Amides Catalyzed by Silica-Bonded S-Sulfonic Acid Nanoparticles

Silica-bonded S-sulfonic acid nanoparticles (SBSSANPs) were easily synthesized from silica nanoparticles and showed to be an efficient catalyst in the synthesis the symmetrical N,N′-alkylidene bisamides. Reaction of aldehydes and amides in the presence of the catalyst afforded the corresponding bisamides in good to excellent yields. The extensive range of substrates suggests general applicability of the method. Reusability of the catalyst, simple workup procedure, and short reaction times are other advantages of this protocol.

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

三氟甲基磺酸锌催化选择性合成2-苄基-4-氯苯酚

在温和条件下,Zn(OTf)2能有效催化氯化苄对对氯苯酚的C-苄基化反应,选择性合成杀菌剂2-苄基-4-氯苯酚（BCP）,合成的优化条件为n(对氯苯酚):n(氯化苄)=1.2:1,催化剂Zn(OTf)2对氯化苄摩尔分数为5%,60 ℃下反应6 h,用硝基甲烷为溶剂,氯化苄转化率和产物BCP的产率分别＞99%和94%。     

Simple,Convenient Method for the Synthesis of Substituted Furan-2(5H)-one Derivatives Using Tin(II) Chloride

Furan-2(5H)-one derivatives have been synthesized by a simple, efficient, one-pot, three-component condensation of anilines, dimethylacetylenedicarboxylate, and aromatic aldehydes in the presence of a catalytic amount of tin(II) chloride in excellent yields.     

A Versatile and Practical Synthesis of 1,1‐Diacetates from Aldehydes Catalyzed by Cyanuric Chloride

Structurally diverse aldehydes are successfully converted into 1,1‐diacetates with acetic anhydride using cyanuric chloride as a mild, convenient and inexpensive catalyst under solvent‐free conditions. The noteworthy features of the present system are shorter reaction times, and mild and solvent‐free conditions. Furthermore, it offers chemoselective protection of aldehydes.     

CoO/SiO2-Al2O3催化剂上苯胺和1,6-己二醇气相高效合成1-苯基氮杂环庚烷

研究了CoO/SiO2-Al2O3催化剂上苯胺和1,6-己二醇气相催化合成1-苯基氮杂环庚烷的反应,并采用N2吸附-脱附、X射线衍射、H2程序升温还原和NH3程序升温脱附技术对催化剂进行表征.结果表明,CoO/SiO2-Al2O3催化剂表现出较高的活性和选择性.当CoO担载量为0.3mmol/g时,催化剂前体在700℃...     

A facile and efficient ZrCl4 catalyzed conversion of aldehydes to geminal-diacetates and dipivalates and their cleavage

A novel, mild and efficient method has been developed for the preparation of geminal-diacetates and dipivalates in high yields through a reaction of aldehydes with acetic anhydride or pivalic anhydride using Zirconium (IV) chloride as a catalyst under solvent free conditions. Regeneration of aldehydes from the acylals was also achieved using the same catalyst in CH₃OH.     

A Novel Chemoselective Reaction of Aldehydes with 2‐Mercaptoethanol Catalyzed by SiO2‐NaHSO4 under Solvent‐free Condition

An efficient and user‐friendly procedure has been developed for the chemoselective protection of aldehyde carbonyl groups such as bis(2‐hydroxyethyl)dithioacetals with 2‐mercaptoethanol catalyzed by silica‐supported sodium bisulphate under solvent‐free conditions. It has been shown that a variety of aldehydes can expeditiously undergo this reaction to produce their corresponding dithioacetals with impressive yields at room temperature.     

离子液体促进四氟硼酸铜催化芳醛和乙酸酐合成1,1-二乙酸酯

在室温条件下, 离子液体1-正丁基-3-甲基六氟磷酸盐([bmim]PF₆)能促进四氟硼酸铜催化一系列芳醛和乙酸酐反应, 以83%～97%的产率生成相应的1,1-二乙酸酯. 在离子液体[bmim]PF₆存在情况下, 催化剂活性远远高于无离子液体存在下的活性. 催化剂用量仅需 0.2 mol%就能使反应顺利进行, 远远少于文献报道的其它催化剂的用量, 反应在3～20 min内完成. 实验结果表明该法催化剂用量少、产率高、反应时间短、离子液体可重复使用、对环境友好.     

Syntheses, Spectroscopic Properties and Crystal Structures of （2-Cl-C6H4CH2）3SnS2CN（C5H10） and （2-Cl-C6H4CH2）3SnS2CN（C4H9N）

1 INTRODUCTION The chemistry of organotin(IV) complexes was extensively studied due to their biological activity and coordination chemistry[1～7]. More recently, phar- maceutical properties of alkyltin(IV) complexes with dithiocarbamate ligands have bee…     

Zn/ ZrCl_4 System Induced Reductive Cleavage of Se-Se Bond in Diaryl Diselenides: A Novel Method for the Systhesis of Selenoesters

In recent years, organoselenium compounds have been extensively used as important synthetic reagents and intermediates in organic synthesis1-3. Among them, selenoesters are very useful intermediates in the synthesis of natural compounds4. While there are many methods for the synthesis of selenoesters, the most common approach is the use of selenide anions reacting with acylation reagents. Selenide anions can be obtained by cleavage of diselenides with sodium in liquid ammonia5 or in THF/H…