scholarly journals P2O5/SiO2as a New, Efficient and Reusable Catalyst for Preparation of 4,4′-Epoxydicoumarins Under Solvent-free Conditions

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.

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 78 (6) ◽  
pp. 769-779 ◽  
Author(s):  
Ali Ghasemzadeh ◽  
Javad Safaei-Ghomi ◽  
Safura Zahedi

Magnetically separable Fe3O4 nanoparticles supply environmentally friendly procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene and 1,8-dioxo-octahydro-xanthene derivatives. These compounds were obtained in high yields and short reaction times by the reaction of dimedone and 2-naphthol with various aromatic aldehydes under solvent-free conditions. The catalyst coluld be easily recovered using an external magnet and reused for six cycles with almost consistent activity.


2018 ◽  
Vol 42 (2) ◽  
pp. 86-89 ◽  
Author(s):  
Mohammad Akrami Abarghooei ◽  
Razieh Mohebat ◽  
Zahed Karimi-Jaberi ◽  
Mohammad Hossein Mosslemin

A new and convenient method is describe d for the synthesis of 3-aryl-benzo[ b]furans and 3-aryl-naphtho[ b]furans by the reaction of various α-bromoketones with phenols and 2-naphthols in the presence of n-propyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride immobilised on SiO2. All products were obtained in high yields and short reaction times using solvent-free conditions and a reusable catalyst.


2007 ◽  
Vol 85 (6) ◽  
pp. 416-420 ◽  
Author(s):  
Alireza Hasaninejad ◽  
Abdolkarim Zare ◽  
Hashem Sharghi ◽  
Mohsen Shekouhy ◽  
Reza Khalifeh ◽  
...  

A simple and efficient solvent-free procedure for the preparation of bis(indolyl)methanes via electrophilic substitution reactions of indoles with aldehydes and ketones is described. The reactions took place in the presence of a catalytic amount of silica chloride at room temperature. The advantages of this method are high yields, short reaction times, low cost, and compliance with green-chemistry protocols.Key words: silica chloride, indole, carbonyl compound, solvent-free, bis(indolyl)methane.


2007 ◽  
Vol 60 (8) ◽  
pp. 590 ◽  
Author(s):  
V. T. Kamble ◽  
R. A. Tayade ◽  
B. S. Davane ◽  
K. R. Kadam

Aldehydes are smoothly converted into the corresponding 1,1-diacetates (acylals) in high yields in the presence of a catalytic amount (0.1 mol-%) of iron(III) fluoride at room temperature. The noteworthy features of the present system are shorter reaction times, chemoselective protection of aldehydes, and solvent-free conditions. The procedure is especially useful for large-scale syntheses as the catalyst is highly effective from the view of activity, selectivity, reusability, and economy in the preparation of 1,1-diacetates (acylals).


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 76 (2) ◽  
pp. 85-90
Author(s):  
Abdolkarim Zare ◽  
Manije Dianat

Abstract A highly efficient and green protocol for the synthesis of pyrimido[4,5-b]quinolines has been described. The one-pot multicomponent reaction of dimedone with arylaldehydes and 6-amino-1,3-dimethyluracil in the presence of N,N-diethyl-N-sulfoethanaminium chloride ([Et3N–SO3H][Cl]) as an ionic liquid (IL) catalyst under solvent-free conditions afforded the mentioned compounds in high yields and short reaction times. Our protocol is superior to many of the reported protocols in terms of two or more of these factors: the reaction times, yields, conditions (solvent-free versus usage of organic solvents), temperature and catalyst amount.


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.


2018 ◽  
Vol 42 (12) ◽  
pp. 604-607
Author(s):  
Loghman Firoozpour ◽  
Hoda Yahyavi ◽  
Ramona Ejtemaei ◽  
Setareh Moghimi ◽  
Alireza Foroumadi

A green and efficient method for preparing novel heterocyclic systems is established through the reaction of differently substituted benzaldehydes, barbituric acid and 4-amino-2H-chromene-2-one under solvent-free conditions. This method affords 6H-chromeno[3’,4’:5,6] pyrido[2,3-d]pyrimidine-trione derivatives in high yields and short reaction times.


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.


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