scholarly journals Cellulose sulphuric acid as a biodegradable and reusable catalyst for the Knoevenagel condensation

2010 ◽  
Vol 8 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Kiran Shelke ◽  
Suryakant Sapkal ◽  
Kirti Niralwad ◽  
Bapurao Shingate ◽  
Murlidhar Shingare

AbstractA green, mild and efficient method for Knoevenagel condensation of 3-formylchromone/2-chlroquinoline-3-carbaldehyde with active methylene compounds such as Meldrum’s acid/ethyl cyanoacetate using biosupported cellulose sulphuric acid (CSA) in the solid-state by grinding under solvent-free condition has been developed. This method provides several advantages including environmental friendliness, shor t reaction times, high yields and a simple work-up procedure. Moreover, the CSA was successfully reused for four cycles without significant loss of activity.

2021 ◽  
Author(s):  
Mojgan Zendehdel ◽  
Fatemeh Tavakoli

Abstract A new class of catalyst has been prepared with sulfunic acid functionalized HY zeolite (HY-N-SO3H) and characterized by FESEM, TEM, FTIR, TGA, XRD and BET. The result show that the catalyst has the micro-meso structure without ordering in the mesophase. Then, two sets of organic reaction were examined to consider of catalytic activity. The micro-meso structure HY-N-SO3H was used as an acidic catalyst to synthesis of coumarins via Pechmann reaction and facile transformation of amines to formamides under solvent free condition. This catalyst was compared with NaY-N-SO3H and MCM-N-SO3H and pure porous material to consider of the effect of acidity and kind and size of porous in the catalyst. The significant advantages of HY-N-SO3H respect to other catalyst are short reaction times, high yields, pure products, mild conditions and easy workup. In addition, we report an original and environmentally friendly solvent-free procedures which reusability of catalyst makes this method nearly green and environmental friendly.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Yuliang Zhang ◽  
Zhongqiang Zhou

A simple and efficient synthesis of 5-arylidene-2,4-thiazolidinediones by the Knoevenagel condensation of aromatic aldehydes with 2,4-thiazolidinedione catalyzed by ethylenediamine diacetate under solvent-free conditions is described. The major advantages of this method are simple experimental and work-up procedures, solvent-free reaction conditions, small amount of catalyst, short reaction time, high yields, and utilization of an inexpensive and reusable catalyst.


2008 ◽  
Vol 86 (8) ◽  
pp. 831-840 ◽  
Author(s):  
Iraj Mohammadpoor-Baltork ◽  
Majid Moghadam ◽  
Shahram Tangestaninejad ◽  
Valiollah Mirkhani ◽  
Arsalan Mirjafari

Different types of primary and secondary alcohols were efficiently transformed to their corresponding methoxymethyl (MOM) and ethoxymethyl (EOM) ethers in the presence of catalytic amounts of H3PW12O40 at room temperature under solvent-free conditions. Selective protection of primary and secondary alcohols in the presence of phenols and tertiary alcohols was achieved by this method. Deprotection of these ethers to their parent alcohols was also performed using this catalyst in ethanol under reflux conditions. We have also found that primary and secondary MOM- and EOM-ethers are selectively deprotected in the presence of phenolic and tertiary ones, methyl and benzyl ethers, esters, and trimethylsilyl ethers by this catalyst. The notable advantages of this protocol are high yields, short reaction times, easy work-up, non-toxicity, easy availability and handling, eco-friendly, and reusability of the catalyst.Key words: methoxymethylation, ethoxymethylation, protection, deprotection, heteropoly acid.


2020 ◽  
Vol 20 (9) ◽  
pp. 5433-5444
Author(s):  
Farhad Shirini ◽  
Fatemeh Kamali

A green magnetic nanocatalyst is developed by immobilization of Fe3O4 on Graphitic carbon nitride (g-C3N4) support for the efficacious synthesis of 5-arylidenepyrimidine-2,4,6-(1H,3H,5H)-trione and pyrano-pyrimidinone derivatives in aqueous media. The most momentous features of the present protocol are the simple preparation of the catalyst, mild reaction conditions, short reaction times and high yields of the products. Moreover, the magnetic nanocatalyst Fe3O4/g-C3N4 can be recycled effectively and reused several times, without a significant loss in reactivity.


Author(s):  
Behrooz Maleki ◽  
Samaneh Sedigh Ashrafi

<p>A simple, green, and efficient method for the synthesis of 2,4,5-triaryl-1<em>H</em>-imidazoles using <em>N</em>-bromosuccinimide (NBS) as a catalyst under solvent-free condition is described. The major advantages of the present method are: high yields, less reaction times, solvent-free conditions, easy purification of the products, environmental friendliness, and convenient operation.</p>


Author(s):  
Amir Khojastehnezhad

Silica supported molybdenum oxide (MoO<sub>3</sub>/SiO<sub>2</sub>) was found to be an efficient, eco-friendly and heterogeneous catalyst for the multicomponent reaction of aromatic aldehydes, dimedone and ammonium acetate or aromatic amines under solvent-free conditions to afford the corresponding 1,8-dioxodecahydroacridines  in high yields. The catalyst can be easily recovered and reused for several times without considerable loss of activity. Furthermore, the present method offers several advantages, such as an easy experimental and work-up procedures, short reaction times and good to excellent yields.


2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Kobra Nikoofar ◽  
Fatemeh Shahriyari

AbstractA simple, straightforward, and ultrasound-promoted method for the preparation of some highly functionalized tetrahydropyridines reported via pseudo five-component reaction of (hetero)aromatic aldehydes, different anilines, and alkyl acetoacetates in the presence of [N-CH2CO2H-3-pic]+HSO4−, as a novel ionic liquid, in green aqueous medium. The IL was synthesized utilizing simple and easily-handled substrates and characterized by FT-IR, 1H NMR, 13C NMR, GC-MASS, FESEM, EDX, and TGA/DTG techniques. The procedure contains some highlighted aspects which are: (a) performing the MCR in the presence of aqua and sonic waves, as two main important and environmentally benign indexes in green and economic chemistry, (b) high yields of products within short reaction times, (c) convenient work-up procedure, (d) preparing the new IL via simple substrates and procedure.


BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Arefeh Dehghani Tafti ◽  
Bi Bi Fatemeh Mirjalili ◽  
Abdolhamid Bamoniri ◽  
Naeimeh Salehi

AbstractNano-eggshell/Ti(IV) as a novel naturally based catalyst was prepared, characterized and applied for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives. The characterization of nano-eggshell/Ti(IV) was performed using Fourier Transform Infrared spectroscopy, X-ray Diffraction, Field Emission Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, and Thermo Gravimetric Analysis. Dihydropyrano[2,3-c]pyrazoles were synthesized in the presence of nano-eggshell/Ti(IV) via a four component reaction of aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate at room temperature under solvent free conditions. The principal affairs of this procedure are mild condition, short reaction times, easy work-up, high yields, reusability of the catalyst and the absence of toxic organic solvents.


2021 ◽  
Vol 18 ◽  
Author(s):  
Abolfazl Olyaei ◽  
Zahra Ghahremany ◽  
Madieh Sadeghpour

: A green and efficient protocol was developed for the one-pot three-component synthesis of novel 2-(4-hydroxy-2-oxo-2H-chromen-3-yl)-2-(arylamino)-1H-indene-1,3(2H)-dione derivatives by the reaction of 4-hydroxycoumarin, ninhydrin and aromatic amines in the presence of guanidine hydrochloride as an organocatalyst under solvent-free conditions. The present approach offers several advantages such as low cost, simple work-up, short reaction times, chromatography-free purification, high yields and greener conditions.


2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Firouzeh Nemati ◽  
Azam Beyzai

A novel one-pot synthesis of 1,2-dihydro-1-arylnaphtho[1,2-e][1,3]oxazine-3-ones by condensation of a variety of aldehydes withβ-naphthol and urea or thiourea in the presence of wet cyanuric chloride under solvent-free condition has been described. High yields, simple procedure, easy workup, short reaction times, and avoiding the use of organic solvent are the advantages of this green methodology.


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