硅胶键合N-丙基二乙烯氨基磺酸作为可回收固体酸催化剂催化合成α-氨基腈(英文)

Silica-bonded N-propyl diethylenetriamine sulfamic acid (SBPDSA) is employed as a recyclable catalyst to synthesize α-aminonitriles. These syntheses involved one-pot condensation of an aldehyde, an amine, and trimethylsilyl cyanide under mild reaction conditions at room temperature. SBPDSA was recycled seven times in the condensation of benzaldehyde, aniline, and trimethylsilyl cyanide without reduction of its catalytic activity.     

Xanthan Sulfuric Acid: An Efficient and Recyclable Solid Acid Catalyst for Pechmann Condensation

In this report, substituted coumarins are formed via Pechmann condensation using various substituted phenols and ethyl acetoacetates in the presence of xanthan sulfuric acid as a solid acid catalyst under solvent-free conditions. This method is very simple, cost-effective, and has shorter reaction times, and the catalyst could be reused.     

Cellulose Sulfuric Acid: An Efficient Biodegradable and Recyclable Solid Acid Catalyst for the Synthesis of 1-Oxo-hexahydroxanthene

A series of 1-oxo-hexahydroxanthene derivatives was synthesized at room temperature in solid state from substituted salicylaldehydes and substituted 1,3-hexanediones in the presence of a catalytic amount of cellulose sulfuric acid. The results showed that the reaction performed under solid-state conditions was benign to the environment, with higher yields and more convenient workup.

Vanadatesulfuric Acid: A Novel,Recyclable, and Heterogeneous Catalyst for the One-Pot Synthesis of Dihydropyrimidinones and Dihydropyrimidinthiones Under Solvent-Free Conditions

Abstract

Vanadatesulfuric acid (VSA), as a novel and heterogeneous catalyst, was used for an efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones (thiones) using an aldehyde, urea, or thiourea and an acyclic β-dicarbonyl compound under solvent-free conditions. VSA is prepared via the reaction of sodium metavanadate and chlorosulfonic acid in high purity. The catalyst was characterized by FTIR, X-ray diffraction (XRD), and transmission electron microscopy (TEM) analysis. Compared to the classical Biginelli reactions, this method consistently has the advantage of high yields, simple workup, short reaction times, and reusability of the catalyst.

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Catalytic Method for Synthesis of Aspirin by a Green,Efficient and Recyclable Solid Acid Catalyst (Preyssler's Anion) at Room Temperature

Synthesis of aspirin at room temperature via O‐acetylation of salicylic acid in the presence of Preyssler type heteropolyacids has been investigated in order to contribute toward clean technology, which is the most important need of the society. All of the catalysts are recyclable and reusable.     

Silica Sulfuric Acid as an Inexpensive and Recyclable Solid Acid Catalyzed Efficient Synthesis of Quinolines

Summary. Silica sulfuric acid as an inexpensive and recyclable solid acid efficiently catalyzes the Fridedl?nder synthesis of quinolines through a condensation reaction of a 2-aminoaryl ketone with an activated α-CH acid compound under solvent-free conditions in high yields at 100°C.     

Silica-bonded S-Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Trisubstituted Imidazoles under Solvent-free Conditions

Trisubstituted imidazoles have been synthesized in high yields in the presence of silica‐bonded S‐sulfonic acid as a catalyst. The reaction was carried out at 130°C under solvent‐free conditions. The reaction work‐up is simple and the catalyst is easily separated from the products by filtration.     

Cellulose Sulfuric Acid: Novel and Efficient Biodegradable and Recyclable Acid Catalyst for the Solid-State Synthesis of Thiadiazolo Benzimidazoles

An efficient method for the synthesis of 2-substituted benzimidazoles has been developed. In this method, benzo[c][1,2,5]thiadiazole-4,5-diamine was condensed with different aldehydes in the presence of cellulose sulfuric acid under solvent-free conditions by simple physical grinding of reactants using a mortar and pestle at room temperature. The methodology is mild, high-yielding, and green, and the catalyst could be easily recycled.     

Melamine Sulfonic Acid: A Recoverable Catalyst for the Ecofriendly Synthesis of Thiocyanohydrins Under Solvent-Free Conditions

Melamine sulfonic acid as a novel and efficient solid acid catalyst has been synthesized and used in the ring opening of epoxides under solvent-free conditions. This catalyst afforded the corresponding thiocyanohydrins with good regioselectivity and very short reaction times. The catalyst can be easily separated and reused several times without appreciable loss of activity. The availability and recoverability of the catalyst with easy operation and workup make this method attractive for organic synthesis.     

Zirconium Phosphate Nanoparticles for Solvent Free Acetylation of Phenols and Salicylic Acid: An Efficient and Eco‐friendly Solid Acid Catalyst for Synthesis of Acetyl Salicylic Acid (Aspirin)

A facile synthesis of zirconium phosphate (ZP) nanoparticles as an effective, eco‐friendly and recyclable solid acid catalyst were studied. PVA was used as the organic matrix which is the dispersing agent and acted as a template for the nanoparticle. It seems H‐bonds between ZP and PVA along polymer chains play an important role in the better dispersion of in situ formed ZP. The catalyst was characterized by several instrumental techniques such as BET, ICP‐OES, XRD, FT‐IR, SEM and TEM. The TPD‐NH₃ analysis suggests the presence of reasonable amount of Brönsted acid sites. The acidic properties of catalyst were studied in acetylation of phenols by acetic anhydride (AA), specifically synthesis of acetylsalicylic acid (ASA), commonly known as Aspirin, from salicylic acid (SA). The effects of reaction time, reaction temperature, mole ratio of reactants, as well as amount of catalysts on the synthesis of ASA were investigated, and the reaction conditions were therefore optimized. The excellent yield (96%) of the ASA was obtained under optimized reaction conditions. The catalyst was recovered from reaction media and reused for 4 times after that with a consistent high yield.     

铌酸催化剂的结构和酸性催化性质

研究了铌酸催化剂的制备方法、表面酸性及晶体结构对乙醇和乙酸酯化反应的影响。结果表明，热处理温度对水洗法制备的铌酸催化剂的催化性能有显著的影响，经３５０℃热处理后其达到活性极大值。并发现催化性能受热处理温度影响的原因是铌酸结构中含水量及比表面积随热处理温度变化而导致铌酸表面酸性的变化，而与氧化铌的形态和晶体结构无明显关系。     

Resin-OsO4-金鸡纳生物碱:一种在(E)-二苯乙烯不对称双羟化反应中可循环使用的高效催化剂

用改进的方法把季铵盐共价结合在Merrifield树脂上作为离子交换剂与K2O5O4作用制成Resin—OsO4催化剂，在NaH存在下，以DMF作溶剂，在70℃下奎宁或奎尼丁与1，4-二氯二氮杂萘反应高产率地生成(QN)2PHAL或(QD)2PHAL，Resin—OsO4通过简单过滤可定量回收，回收的催化剂重复使用五次，其活性不变，Resin—OsO4-(QN)2PHAL或(QD)2PHAL催化体系在(E)-二苯乙烯的不对称双羟化反应中的化学产率为84～91％，立体选择性为96-99％ee。     

Xanthan Sulfuric Acid: An Efficient Bio‐supported and Recyclable Solid Acid Catalyst for the Synthesis of 2‐Aryl Thiadiazolo Benzimidazoles

Xanthan sulfuric acid is an efficient solid acid catalyst for the preparation of 2‐aryl benzimidazoles in excellent yields. This method is applicable for the reaction of benzo[c][1,2,5]thiadiazole‐4,5‐diamine with aldehydes by simple physical grinding at room temperature. The salient features of the present methodology is cheaper process, easy synthesis of stable catalyst and the catalyst can be easily recycled without significant loss of activity.     

水热法简单高效合成三聚氰酸

以三聚氰胺为原料,通过热聚合和水热处理,简单高效地合成了三聚氰酸。 通过用X射线单晶衍射(XRD)、核磁共振波谱仪(NMR)、傅里叶变换红外光谱仪(FTIR)、质谱和元素分析仪对产物进行了结构表征。 在最优的水热反应温度140 ℃下,反应2 h,总产率可达54%。 该合成方法工艺简单,污染少,为工业制备三聚氰酸提供了一种新的参考方案。     

硅胶键合的N-丙基三亚乙基四胺氨基磺酸作为可回收固体酸催化剂催化合成2-氨基-4,6-二芳基烟腈(英文)

A simple and efficient procedure for the preparation of silica-bound N-propyl triethylenetetramine sulfamic acid(SBPTETSA) by the reaction of silica-bound N-propyl triethylenetetramine(SBPTET) with chlorosulfonic acid in chloroform is described.Silica-bound N-propyl triethylenetetramine sulfamic acid was employed as a recyclable catalyst for the synthesis of 2-amino-4,6-diarylnicotinonitriles from the multi-component reaction of an acetophenone derivative,an aromatic aldehyde,malononitrile,and ammonium acetate under solvent-free conditions at 100 °C.The heterogeneous catalyst was recycled for five consecutive runs in the optimized multi-component reaction of 4-chloroacetophenone,4-chloroenzaldehyde,malononitrile,and ammonium acetate without significant loses to its catalytic activity.     

Silica Phosphoric Acid: An Efficient and Recyclable Catalyst for the Solvent-Free Synthesis of Acylals and Their Deprotection in MeOH

Silica phosphoric acid was used as an efficient, mild, and recyclable solid catalyst for the synthesis of acylals from various structurally diverse aldehydes and acetic anhydride under solvent-free conditions. The acylation of aldehydes was highly chemoselective, and no ketone was acylated, which provided a method for the synthesis of acylals from aldehydes in the presence of ketones. Silica phosphoric acid–catalyzed deprotection of acylals to the corresponding aldehydes in MeOH has also been developed with excellent yield. The deprotection of the acylals of aromatic aldehydes took priority over those of aliphatic aldehydes.     

一种高效可循环的有机介孔树脂负载的N-杂卡宾络合钯催化剂催化的Sonogashira反应

新型有机介孔材料FDU-15负载卡宾配体络合醋酸钯催化剂FDU-NHC/Pd(Ⅱ)的制备方法简单,通过三步反应即可制得,采用X射线衍射、N2吸附-脱附和透射电镜等手段对催化剂进行了表征,并考察了它在Sonogashira偶联反应中的催化性能.结果表明,功能化不影响FDU-15的有序介孔结构,仅其孔径、孔体积和BET比表...     

Preparation of Silica-Bonded S-Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Bis-Indolylmethanes

Silica bonded S-sulfonic acid (SBSSA) was prepared by the reaction of 3-mercaptopropylsilica (MPS) and chlorosulfonic acid in chloroform. Silica-bonded S-sulfonic acid, as a reusable solid acid catalyst, was used for the condensation reactions of indole with carbonyl compounds at ambient temperature. Tetra-(indolyl)methanes were also obtained by the condensation reaction of indole with dialdehyde compounds. Silica bonded S-sulfonic acid was recovered and reused.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.