Aldol Condensations Catalyzed by PEG400 and Anhydrous K2CO3 Without Solvent

Abstract

Aldol condensations of aromatic aldehydes with ketones under solvent‐free conditions to synthesize α,β‐unsaturated ketones in good to excellent yields using PEG400 and powdered anhydrous K₂CO₃ as catalysts at 90 °C and 120 °C are described.     

Practical Preparation of Esters and Thioacetates from Alkyl Halides and Carboxylates or Thioacetate Catalyzed by PEG400 without Solvent

Carboxylic esters and thioacetates were conveniently prepared in good to excellent yields under mild conditions by the reaction of alkyl halides with sodium carboxylates or sodium thioacetate catalyzed by PEG400 in the absence of solvents.     

Facile Preparation of Aryl Sulfides Catalyzed by PEG400 and Nickel without Solvent

A variety of aryl sulfides were synthesized by aryl bromides with thiols, with PEG400 and nickel as catalysts under basic conditions in the absence of solvents. This article reported an easy and convenient method for formation of aryl‐sulfur bonds.     

Knoevenagel Condensation of Aromatic Aldehydes with Active Methylene Compounds using a Catalytic Amount of Iodine and K2CO3 at Room Temperature

A convenient method for Knoevenagel condensation of aromatic aldehydes with malononitrile or ethyl cyanoacetate has been developed using the inexpensive and environmentally friendly reagent I₂/K₂CO₃ at room temperature. The method is mild and simple with good to high product yields.     

One‐pot Synthesis of Octahydroqinazolinones Derivatives Catalyzed by [C4(mim)2](FeCl4)2 under Solvent Free Conditions

In this investigation, a practical green chemistry procedure for synthesis of octahydroqinazolinones and thiones derivatives via condensation of aldehyde, 1,3‐cyclohexanedione/dimedone and urea or thiourea catalyzed by magnetic room temperature dicationic liquid under solvent free conditions is described. The catalyst was studied by UV spectroscopy, vibrating sample magnetometer, and thermogravimetric analysis. This methodology is of interest due to several advantages such as environmental benign, easy experimental procedure, good yield and reusable catalyst.     

Recyclable and reusable NiCl2(PPh3)2/CuI/PEG‐400/H2O system for the sonogashira coupling reaction of aryl iodides with alkynes

A stable and highly efficient NiCl2(PPh₃)₂/CuI/PEG‐400/H₂O catalytic system for the Sonogashira reaction has been developed. In the presence of NiCl₂(PPh₃)₂ and CuI, the coupling reaction of aryl iodides with terminal alkynes was carried out smoothly in a mixture of poly(ethylene glycol) (PEG‐400) and water at 100°C with K₂CO₃ as base to afford a variety of arylacetylenes in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether, and the NiCl₂(PPh₃)₂/CuI/PEG‐400/H₂O system could be easily recycled and reused six times without significant loss of catalytic activity. Our system not only avoids the use of easily volatile organic solvents but also solves the basic problem of catalyst reuse. Copyright © 2015 John Wiley & Sons, Ltd.     

Condensation of Aryl Aldehydes, 2‐naphthol,and Thioacetamide Catalyzed by N‐halo Reagents in Neutral Media

A new three‐component, highly efficient and solvent‐free approach for the synthesis of known and new 1‐thioamido‐alkyl‐2‐naphthol derivatives was investigated. This was achieved via a one‐pot condensation by reacting aryl aldehydes, 2‐naphthol, and thioacetamide in the presence of catalytic amount of 1,3,5‐trichloro‐1,3,5‐triazinane‐2,4,6‐trione (TCCA) and 1,3‐dichloro‐5,5‐dimethylhydantoin (DCDMH). Mechanistically, the in situ generation of Cl⁺ ion from TCCA and DCDMH is proposed to catalyse the reactions in neutral media. In the presented work, most of the products have been reported for the first time.     

PEG‐Supported Sulfonic Acid as an Efficient and Recyclable Catalyst for the Synthesis of 1,1‐Diacetates under Solvent‐Free Conditions

An operationally simple, efficient, and environmentally benign synthesis of 1,1‐diacetates in good yields by reaction of different aldehydes with acetic anhydride in the presence of PEG‐supported sulfonic acid under solvent‐free conditions is described.     

功能化离子液体氯化1-(2-羟乙基)-3-甲基咪唑噁盐催化的Knoevenagel缩合反应

在无溶剂条件下 ,采用催化量的功能化离子液体氯化 1 甲基 3 羟乙基咪唑盐作为催化剂 ,在 80℃条件下顺利地催化一系列芳醛和活泼亚甲基化合物进行Knoevenagel缩合反应 ,以 82 %～ 97%的产率生成相应E 式烯烃 .反应在中性条件下进行 ,条件温和 ,产率高 ,操作和后处理简单方便     

A Practical Iodination of Aromatic Compounds by Using Iodine and Iodic Acid

This article describes simple and efficient method for the iodination of different aromatic amines, hydroxy aromatic aldehydes, hydroxy acetophenones and phenols using iodine and iodic acid in ethanol as a solvent. Notable advantages include mild reaction condition, no need of catalyst, short reaction time, simple practical procedure, giving excellent yield of the product.     

A green and efficient method for synthesis of benzimidazoles using nano‐Fe3O4 in PEG‐400/H2O aqueous system under ambient conditions at room temperature

In this paper, a green and facile protocol was described which was efficient for synthesis of benzimidazoles using nano‐Fe₃O₄ catalyst with continuous bubbling of air as the oxidant in PEG‐400/H₂O aqueous system at room temperature. This protocol afforded the target products in good to excellent yields and the catalytic system could be recycled and reused without significant loss of catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.     

A Straightforward Method for the Synthesis of Functionalized Trisubstituted Alkenes through Na2S/Al2O3 Catalyzed Knoevenagel Condensation

Na₂S/Al₂O₃ catalyzed the Knoevenagel condensation between an aldehyde and an active methylene compound to yield various trisubstituted alkenes.     

Aminopropylated PEG as a novel,eco‐friendly and biodegradable basic catalyst for bis‐Michael addition to α,β‐unsaturated ketones under solvent‐free conditions

A solvent‐free and highly efficient protocol has been developed for the synthesis of novel bis‐Michael addition products ( 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , 3l , 3m , 3n , 3o ) using aminopropylated PEG‐6000 (NH₂‐PEG) as a biodegradable and recyclable catalyst in excellent yields under solvent‐free conditions. Other remarkable features of this environmentally benign protocol are shorter reaction time, tolerance of a wide range of C―H‐activated acids, high yield of products, and simple experimental and work‐up procedure as compared to conventional methods. The NH₂‐PEG catalyst is characterized by using FT‐IR, powder XRD and scanning electron microscopy–energy dispersion X‐ray spectrometric analyses. The catalyst can be recycled several times without significant loss of its catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.     

Solvent‐Free Stereoselective Synthesis of cis‐1‐Carbomethoxy‐2‐Aryl‐3,3‐Dicyanocyclopropanes by Grinding

Abstract

The novel route of high stereoselective synthesis of cis‐1‐carbomethoxy‐2‐aryl‐3,3‐dicyanocyclopropanes by grinding is described. This process is simple, efficient, and environmentally benign.     

Ultrasonicated Condensation of Indene and 2-Nitrofluorene with Aromatic Aldehydes Catalyzed by bis-(pMethoxyphenyl)telluroxide (BMPTO)

The condensation of indene or 2-nitrofluorene with aromatic aldehydes catalyzed by bis-(p-methoxyphenyl)telluroxide (BMPTO) under ultrasonic wave irradiation gave corresponding fulvenes in fair to good yield.     

FeCl3-Catalyzed Condensation of 2-Naphthol and Aldehydes under Solvent-Free Reaction Conditions: An Efficient and Green Alternative for the Synthesis of 14-Aryl(Alkyl)-14-H-dibenzo[a, j]xanthenes

An iron‐catalyzed condensation of 2‐naphthol with aldehydes has been described. In the presence of a catalytic amount of iron(III) chloride (5 mol%), the condensation reaction of 2‐naphthol and aldehydes underwent smoothly to generate the corresponding products in good to excellent yields under base‐, acid‐, ligand‐, additive‐, and solvent‐free reaction conditions.