Synthesis of 2-Arylbenzimidazoles in Water

A simple and efficient procedure for the synthesis of 2-arylbenzimidazoles through a one-pot condensation of o-phenylenediamines with aryl aldehydes in water is described. Short reaction time, large-scale synthesis, easy and quick isolation of the product, and excellent yield are the main advantages of this procedure.     

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.     

New Procedure for Obtaining Indomethacin

A new procedure has been developed for the synthesis of indomethacin by the Fischer reaction, based on the acylation of sodium 2-(4-methoxyphenyl)-1-hydrazosulfonate with 4-chlorobenzoyl chloride and subsequent interaction with levulinic acid in the presence of formic acid.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 530–532, April, 2005.     

An Unexpected Role of Carbon Disulfide: A New and Efficient Method for the Synthesis of 2‐Substituted Benzimidazoles

A new and efficient methodology for the synthesis of 2‐substituted benzimidazoles is described. In this procedure, CS₂ unexpectedly facilitated the cyclization reaction between benzene‐1,2‐diamine and benzenecarbaldehydes in CH₂Cl₂ at room temperature. The reactions occur under mild conditions require simpler equipment and easier workup procedures.     

新型席夫碱大环化合物的合成

利用Mn^2＋, Ba^2＋作为模板离子, 由邻苯二胺和α,ω-二(3'-羟基-4'-甲酰苯氧基)取代烷[即1,4-二(3'-羟基-4'-甲酰苯氧基)丁烷、1,6-二(3'-羟基-4'-甲酰苯氧基)己烷、1,8-二(3'-羟基-4'-甲酰苯氧基)辛烷]反应分别合成了系列新型大环席夫碱化合物Lⁿ (n＝4, 6, 8). Mn^2＋用于L⁴合成, 并在洗涤时自动解络; L⁶和L⁸的合成以Ba^2＋模板, L⁶和L⁸的Ba^2＋配合物经与Na₂SO₄水溶液反应解络, 得到自由大环配体L⁶和L⁸. 上述新型大环席夫碱化合物采用元素分析, ¹H NMR, IR, 紫外-可见光谱和MS等进行组成和结构表征.     

Microwave-Assisted Direct Synthesis of 4H-1,2,4-Benzothiadiazine 1,1-Dioxide Derivatives

Abstract

We describe a rapid and convenient methodology for the preparation of diverse 3-aryl and 3-trifluoromethyl 4H-1,2,4-benzothiadiazine-1,1-dioxides in a one-pot microwave-promoted reaction between 2-aminobenzenesulfonamides and benzaldehydes, trifluoroacetic acid or benzoic acids.

GRAPHICAL ABSTRACT      

白藜芦醇的合成新方法

本文探索了合成白藜芦醇的新方法。以3,5-二甲氧基苯胺为原料,经重氮化、还原及乙酰化得到中间体N′-乙酰基-3,5-二甲氧基苯肼(4),中间体4与4-甲氧基苯乙烯经Mizoroki-Heck偶联反应得中间体5,脱去甲基即得到目标产物白藜芦醇,总收率约31.9%。中间体及目标产物的结构均经质谱及核磁氢谱确证。该路线操作简便、条件温和,可用于白藜芦醇的放大制备。     

Synthesis of Some New Pyrimidothienopyridazines and Related Heterocycles

5‐Amino‐3,4‐diphenylthieno[2,3‐c]pyridazine‐6‐carbonitrile 2a was reacted with propylene diamine to give tetrahydropyrimidinyl derivative 3 . The latter compound ( 3 ) underwent certain cyclocondensation reactions to produce pyrimidothienopyridazines 4–6 . Also, the reactions of 5‐amino‐3,4‐diphenylthieno[2,3‐c]pyridazine‐6‐carboxamide with heterocyclic aldehydes and/or cycloalkanones were carried out and their products were identified. Moreover, some novel pyridazinothienopyrimidobenzimidazoles 14–17 were synthesized.     

A MILD METHOD FOR CONVERSION OF ALCOHOLS TO DIALKYL SULFITES BY USE OF Na2SO3/SOCl2

Alcohols are easily converted to their corresponding dialkyl sulfite under mild reaction conditions using Na₂SO₃/SOCl₂ in moderate to good isolated yields.     

Asymmetric Synthesis of Allylic Sulfonic Acids: Enantio‐ and Regioselective Iridium‐Catalyzed Allylations of Na2SO3

An enantioselective allylation reaction of allylic carbonates with sodium sulfite (Na₂SO₃) catalyzed by Ir complex was accomplished, providing allylic sulfonic acids in good to excellent yields with a high level of enantio‐ and regioselectivities. (R)‐2‐Phenyl‐2‐sulfoacetic acid, a key intermediate for the synthesis of Cefsulodin and Sulbenicillin, was synthesized as well.     

An expedient esterification of aromatic carboxylic acids using sodium bromate and sodium hydrogen sulfite

Treatment of aromatic carboxylic acids and substituted toluenes with a mixture of sodium bromate and sodium hydrogen sulfite in a two-phase system gave the corresponding esters in good yield. The intermediate α-brominated toluene was formed by the in situ generated hypobromous acid. The α-bromotoluene underwent an intermolecular nucleophilic substitution reaction with aromatic carboxylic acids present in the reaction mixture to afford the corresponding esters.     

New Preparative Procedure for the Synthesis of Chloroalkyl Sulfides

Reaction of thiols with dihaloalkanes in the system hydrazine hydrate-base leads to alkyl(chloroalkyl) sulfides with different positions of the chlorine atom with respect to sulfur. The developed one-step procedure for the synthesis of such unsymmetrical sulfides is most suitable for arenethiols and alkanethiols having a long polymethylene chain. The reaction mechanism is discussed.     

Synthesis of benzimidazoles from o-phenylenediamines and DMF derivatives in the presence of PhSiH3

A simple approach to preparation of benzimidazoles from o-phenylenediamines and DMF derivatives, only employing PhSiH₃ as promoter without any other additives, was reported. This route provided moderate to high yields with a broad substrate scope. A plausible mechanism for the reaction is proposed based on the spectroscopic characterization (e.g., HRMS and ¹H NMR) of the reaction mixture.     

CuBr-Catalyzed Oxidation/Coupling: An Efficient and Applicable Strategy for the Synthesis of 2-Aryl Benzimidazoles from 1-Fluoro-2-nitrobenzene and Benzylamines

A novel and efficient route has been developed for the synthesis of benzimidazole derivatives via ligand-free CuBr-catalyzed oxidation and cyclization of 1,2-diamines derived from 1-fluoro-2-nitrobenzene and different arylamines as starting materials.     

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.     

The Effect of the Conditions of Catalytic Synthesis of Nanoparticles of Metallic Silver on Their Plasmon Resonance

The formation of nanoparticles of metallic silver in the reduction of Ag⁺ ions catalyzed by colloidal Ag₂S was investigated. It was established that the position of the surface plasmon resonance bands of the Ag nanoparticles is affected by the concentration of the catalyst, its particle size and the amount of particles with the same size, the stabilization conditions, the concentration of Ag⁺ ions, and the temperature at which the process is conducted. An explanation for the spectral changes that occur is proposed.     

合成有机锗倍半硫化物的新方法

有机锗倍半硫化物的合成是有机锗抗癌药物研究中的热点之一。在路易斯碱(如吡啶或三乙胺)存在下,经有机锗三氯化物溶液中通干燥的硫化氢气体制得有机锗倍半硫化物的方法有许多缺点,如无法计算吸收的硫化氢的量、设备复杂、操作困难并产生硫化氢臭味和毒性。我们用无水硫化钠直接与有机锗三氯化物作用即可得到有机锗倍半硫化物。利用此法合成了8种有机锗倍半硫化物:     

Synthesis and Crystal Structure of Sodium Monosulfuron (N-(4-Methylpyrimidin-2-yl)-N'-2-(nitrophenylsulfonyl) Urea Sodium)

Monosulfuron is a novel sulfonylurea herbicide with ultra-low dosage invented and patented by Nankai University.Herein its sodium salt was firstly synthesized and crystal structure was determined by X-ray diffraction method.The title compound belongs to the triclinic system, space group P1- with a = 7.306(6), b = 9.446(8), c = 11.872(10)(A), α= 76.578(14), β= 78.049(13), γ= 77.620(14)°, V = 767.7(11)(A)3, Mr = 377.32, Z = 2, Dc = 1.632 g/cm3,μ= 0.283 mm-1, F(000) = 388, R = 0.0444 and wR = 0.1186.In the title compound, Na(1) coordinates with O(4) and O(5) from one monosulfuron molecule, N(4A) and O(5A) from the other monosulfuron molecule and the oxygen atom from H2O to give five coordination bonds.The title complex is further linked into a three-dimensional structure through π…π interactions and intermolecular hydrogen bonds between the oxygen and nitrogen atoms.     

Synthesis of Benzopyran Derivatives,XIV: New Procedure for the Preparation of 2,2-Dimethyl-2H-chromenes

2,2-Dimethyl-4-methoxychromans (1–12) have been converted into 2,2-dimethyl-2H-chromenes (13–24) in acidic media.     

碘促进的苯并咪唑及其衍生物的合成

在碘的氧化作用下,由伯醇和邻苯二胺一步合成了苯并咪唑及其衍生物。考察了碘和碳酸钾用量及温度对反应产率的影响,反应较佳的条件为n(o-ClC6H4CH2OH)∶n(o-phenylenediamine)∶n(I2)∶n(K2CO3)=1.0∶1.1∶5.0∶5.0,反应温度70℃,反应时间5 h。用方法A在较佳的反应条件下2-(2-氯苯基)苯并咪唑的产率可达86%,用方法B其产率达69%。没有选择传统的醛或酸作为反应底物,而是选择了伯醇在碘的氧化作用下直接合成了目标产物,反应为合成苯并咪唑及其衍生物的一个新方法,探讨了可能的反应机理。