超声辐射下NH4OAc高效催化合成2-取代苯并咪唑类衍生物（英文）

超声辐射下,以NH4OAc为催化剂,利用芳香醛和邻苯二胺一锅法合成了一系列2-取代苯并咪唑类衍生物,该方法具有反应条件温和、收率高的特点。     

苯并咪唑衍生物的合成改进

利用空气作氧化剂, 无需任何催化剂, 以甲醇作溶剂, 芳香醛与邻苯二胺反应一步合成苯并咪唑衍生物, 产率均超过69%, 产物的结构通过元素分析、红外光谱和核磁共振氢谱确证, 该方法具有操作简单、反应条件温和、环境友好的优点.     

环状磷酸催化合成2-取代苯并咪唑

以邻苯二胺和醛为原料,四氢呋喃为溶剂,在环状磷酸催化下,室温下合成了一系列2-取代苯并咪唑化合物.考察了催化剂种类、用量和溶剂对反应的影响,确定了最优反应条件,提出了可能的反应机理.该反应具有操作简单,条件温和,产率高及环境友好等优点.     

微波辐射下2-苯并咪唑的绿色合成

以氯化铵为催化剂,以分子氧为绿色氧化剂,邻苯二胺和芳香醛为原料,微波辐射下高选择性地合成了一系列2-取代苯并咪唑类化合物。其结构经元素分析、IR、NMR得以确证,结果与文献值相符。该方法与传统方法相比,具有反应时间短,后处理简单、选择性好等优点。     

邻苯二胺与醛反应合成苯并咪唑衍生物的反应机理研究

以4-甲基苯甲醛与邻苯二胺反应合成2-(4-甲基苯基)苯并咪唑的反应为例,以HPLC方法跟踪反应进程,对关键中间体与产物的结构通过1H NMR,FT-IR及LC-MS等手段进行了表征.实验证明了在邻苯二胺和醛物质的量比为1:1时同时生成单席夫碱和双席夫碱中间体的反应机理,并提出了该类反应的影响规律.     

微波辐射下2-取代苯并咪唑衍生物库的平行合成

以邻苯二胺及相应羧酸为原料,于多聚磷酸存在下,由微波辐射平行合成了一个小型2-取代苯并咪唑衍生物库,反应时间由常规加热的几小时到几天缩短为20min,且产率较高。经元素分析和1H NMR确证了产物结构。     

无溶剂微波照射下2－取代苯并咪唑的合成

用PPA作催化剂，在无溶剂微波照射下合成了10种2－取代苯并咪唑，为该类化 合物的合成提供了一种新方法。与常规方法相比，反应时间大大缩短，产率与传统 合成方法相当。     

微波法合成取代环己烷

采用微波辐射技术,由甲基酮和芳香醛合一步合成了一组新的取代环己烷,产率高于８５％,产物单一,提纯方便,反应时间短。     

2-取代苯并眯唑合成工艺的改进

以邻苯二胺和有机酸为原料,在磷酸和多聚磷酸混合酸的催化下合成了四种2-取代苯并咪唑化合物。利用红外光谱、核磁氢谱、熔点测定等方法对产物进行了结构表征。讨论了反应温度、催化剂用量对收率的影响。该合成工艺较原有的工艺得以完善,收率有较大提高。     

FeCl3-Doped Polyaniline Nanoparticles as Reusable Heterogeneous Catalyst for the Synthesis of 2-Substituted Benzimidazoles

FeCl₃-doped polyaniline nanoparticles efficiently catalyze the synthesis of 2-substituted benzimidazoles by the reaction of aldehydes with o-phenylenediamine. Synthesis and characterization of the catalyst are described, and the obtained results confirms good dispersion of the FeCl₃ on the polyaniline. Simple workup, mild reaction conditions, low cost, easy separation, and reusability of the catalyst are some advantages of this method.     

氧化铝和氧化锆催化剂上2-取代苯并咪唑和1,5-二取代苯并二氮的合成(英文)

In this study, alumina, zirconia, manganese oxide/alumina, and manganese oxide/zirconia have been investigated for their catalytic activity in the condensation reaction between o-phenylenediamine and an aldehyde or a ketone to synthesise 2-substituted benzimidazoles and 1,5-disubstituted benzodiazepines respectively. Surface area, surface acidity, and morphology of the catalysts have been analysed and correlated with their catalytic activity. The isolated yields of 2-substituted benzimidazoles and 1,5-disubstituted benzodiazepines are in the range of 30% to 95%. A good correlation between the amount of surface acid sites as well as the surface morphology of the catalysts and the catalytic activity has been observed. This method has been found to be simple and economical. The solid supports could be regenerated and reused without much loss in their activity. Further, the solid supports have been also found to be effective as general catalysts in the condensation of o-phenylenediamine with other substituted aldehydes and ketones.     

Synthesis of 1-Substituted Benzimidazoles Using N,N'-Thionyldibenzimidazole or N-Chlorosulfinylbenzimidazole

N,N'-Thionyldiimidazole has been known as an imidazole transfer reagent^2–4 and form a new class of compound with a wide range of synthetic application. Continuing our studies on the imidazole transfer reaction, we succeeded with the benzimidazole transfer reaction using N,N'-thionyldibenzimidazole. The present communication deals with a new procedure providing 1-substituted benzimidazoles.     

Efficient and Inexpensive Synthesis of Benzimidazoles and Quinoxalines

o-Phenylenediamines were reacted with carbonyl compounds, β-ketoesters, and 1,2-diketones in presence of ammonium salts to give benzimidazoles and quinoxalines in very good yields. Ammonium salts are commercial and environmentally benign catalysts.     

Efficient One-Pot Synthesis of Benzimidazoles Under Solvent-Free Conditions

A green, efficient method for the synthesis of various 2-aryl-benzimidazoles in the presence of hypervalent iodine as the oxidant at room temperature under solvent-free conditions is reported. The salient features of this method include mild conditions, short reaction times (3–5 min), excellent yields, and simple procedure.     

Synthesis of 2-Substituted Benzimidazoles, Benzoxazoles, and Benzothiazoles from Arylsulfonyl(thio)propionitriles

The reaction of nitriles and of methyl imino ester hydrochlorides of arylsulfonyl(thio)propionic acids with o-phenylenediamine, o-aminophenol, and o-aminothiophenol has been studied. A series of new 2-substituted benzazoles has been synthesized containing arylsulfonyl(thio)propionic acid fragments.     

Simple and Efficient One-Pot Synthesis of 2-Substituted Benzoxazole and Benzothiazole

2-Substituted benzoxazole and benzothiazole were synthesized from condensation of aldehyde and 2-aminophenol or 2-aminothiophenol via a one-pot process using diethyl bromo phoshonate and tert-butyl hypochlorite.     

Solid Acid Supported on Magnetic Nanoparticles as a Highly Efficient and Retrievable Catalyst for the Synthesis 2-Substituted Benzothiazoles

Russian Journal of General Chemistry - The use of a recyclable heterogeneous nanomagnetic solid acid catalyst, [Fe3O4@SiO2@(CH2)3NPC–SO3H]Cl, in a simple and highly efficient synthesis of...     

Antimony Trioxide as an Efficient Lewis Acid Catalyst for the Synthesis of 5-Substituted 1H-Tetrazoles

Sb₂O₃ was found to be effective as a catalyst for a smooth (2 + 3) cycloaddition of sodium azide with nitriles to afford 5-substituted 1H-tetrazoles in good yields.