H3PW12O40 — A selective, environmentally benign, and reusable catalyst for the preparation of methoxymethyl and ethoxymethyl ethers and their deprotections under mild conditions

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.

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.


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.


2011 ◽  
Vol 76 (4) ◽  
pp. 235-241 ◽  
Author(s):  
Li-Qiang Wu ◽  
Wei-Lin Li ◽  
Fu-Lin Yan

A series of new 8-aryl-7,8-dihydro[1,3]dioxolo[4,5-g]chromen-6-ones were synthesized via a three-component reaction of 3,4-methylenedioxyphenol, aromatic aldehydes and Meldrum’s acid in the presence of CeCl3·7H2O under solvent-free conditions. The method provided several advantages such as easy work-up, high yields and environmentally benign procedure.


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.


2011 ◽  
Vol 8 (4) ◽  
pp. 1626-1631 ◽  
Author(s):  
Liqiang Wu ◽  
Xiao Wang

An efficient solvent-free procedure for the preparation of 4,4′-epoxydicoumarins via the ondensation of 4-hydroxycoumarin with aldehydes in the presence of catalytic amount of phosphorus pentoxide/silica gel at 110°C is described. The advantages of this method are generality, high yields, short reaction times, ease of product isolation, low cost and ecologically friendly.


2008 ◽  
Vol 2008 (11) ◽  
pp. 642-643 ◽  
Author(s):  
Yi Hu ◽  
Hui Kang ◽  
Bi-Wen Zeng ◽  
Ping Wei ◽  
He Huang

A series of 3-arylidene-1,3-dihydroindol-2-one derivatives were conveniently synthesised by the condensation of aromatic aldehydes with 1,3-dihydroindol-2-one using a Brønsted acidic ionic liquid as a dual solvent-catalyst. This method has the advantages of short reaction times, simple work-up, high yields with high purity, being environmentally benign and the ionic liquid can be reused.


2012 ◽  
Vol 9 (4) ◽  
pp. 2037-2043 ◽  
Author(s):  
Abolghasem Davoodnia ◽  
Bahareh Razavi ◽  
Niloofar Tavakoli-Hoseini

Silica gel-supported polyphosphoric acid (PPA-SiO2) was found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst for the synthesis of 2,4,6-triarylpyridines through one-pot three-component reaction of acetophenone, aryl aldehydes, and ammonium acetate under solvent-free conditions. This method has several advantages, such as simple procedure with an easy work-up, short reaction times, and high yields. Furthermore, the catalyst could be recycled after a simple work-up, and used at least three times without substantial reduction in its catalytic activity.


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