Molybdate sulfonic acid: preparation, characterization, and application as an effective and reusable catalyst for octahydroxanthene-1,8-dione synthesis

Molybdate sulfonic acid (MSA) as a highly efficient catalyst was synthesized and employed for the synthesis of octahydroxanthene-1,8-dione derivatives. MSA efficiently catalyzed condensation of a wide range of aryl aldehydes and cyclohexane-1,3-diones to obtain octahydroxanthene-1,8-diones. It was characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), and FT-IR spectroscopy. This catalyst can be recovered and reused several times in other reactions maintaining its high activity. This novel and green method is very cheap and has many advantages such as excellent yields, the use of recoverable and eco-friendly catalysts, and a simple work-up procedure.     

Synthesis of 1,8-dioxooctahydroxanthenes utilizing PMA-SiO_2 as an efficient reusable catalyst

PMA-SiO2 has been utilized as an efficient catalyst system in preparation of 1,8-dioxooctahydroxanthenes.     

Polyethylene glycol-mediated synthesis of decahydroacridine-1,8-diones catalyzed by ceric ammonium nitrate

Polyethylene glycol was found to be an inexpensive non-toxic and effective medium for one pot synthesis of high yields of decahydroacridine-1,8-diones in the presence of ceric ammonium nitrate as the catalyst. Moreover, the solvent can be recovered and reused.     

Nanocrystalline TiO2, via green combustion synthesis,as an efficient and reusable catalyst for the preparation of 1,8‐dioxooctahydroxanthenes and 1,8‐dioxodecahydroacridines

Nanocrystalline TiO₂ is synthesized using a green combustion method and used as a recyclable catalyst for the one‐pot multicomponent synthesis of 1,8‐dioxodecahydroacridines and 1,8‐dioxooctahydroxanthenes, under solvent‐free conditions. This method is mild, environmentally friendly, inexpensive and highly effective for obtaining good to excellent yields of the products. Copyright © 2015 John Wiley & Sons, Ltd.     

Melamine trisulfonic acid as a new, efficient and reusable catalyst for the solvent free synthesis of coumarins

Melamine trisulfonic acid (MTSA) is easily prepared by the reaction between melamine and neat chlorosulfonic acid at room temperature. This compound can be used as an efficient and recyclable catalyst for the synthesis of coumarins via von Pechmann condensation reaction under solvent-free conditions.     

PEG-SO3H as an efficient and reusable catalyst for chemoselective synthesis of 1,1-diacetates

An efficient and convenient procedure of the synthesis of 1,1-diacetates from aromatic aldehydes and acetic anhydride under mild and solvent-free conditions at room temperature,in the presence of PEG-SO₃H is reported.PEG-SO₃H acts as a catalyst and can be recovered and reused eight times without apparent loss of its catalytic activity.     

Carbon-based nanocatalyst: An efficient and recyclable heterogeneous catalyst for one-pot synthesis of gem-bisamides,hexahydroacridine-1,8-diones and 1,8-dioxo-octahydroxanthenes

Journal of the Iranian Chemical Society - In this abstract, we discuss the progress related to sulfonated carbon-based materials in various acid-catalyzed organic transformations which are then...     

One-pot,four-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones catalyzed by cellulose-SO3H as a reusable heterogeneous and efficient catalyst

A practical and green method for the synthesis of 2H-indazolo[2,1-b]phthalazine-1,6,11(13H)-trione derivatives using cellulose-SO₃H as a solid acidic catalyst for the four-component condensation reaction of hydrazinium hydroxide, phthalic anhydride, dimedone, and aromatic aldehydes under thermal solvent-free conditions is described. Cellulose-SO₃H as a recyclable green chemical compound has been demonstrated as a new catalyst for the synthesis of this class of compounds.     

An appropriate one-pot synthesis of dihydropyrimidinones catalyzed by heteropoly acid supported on zeolite: An efficient and reusable catalyst for the Biginelli reaction

A mild and efficient catalytic method has been developed for the synthesis of 3,4-dihydropyrimidin-2 (1H)-ones (DHPM) by a one-pot three-component cyclocondensation reaction using molybdophosphoric acid (MPA) supported on Y zeolite in high to excellent yields. The reaction investigated in the presence of molybdophosphoric acid encapsulated in the supercage of zeolite for comparison. In the second method, no appreciable progress was observed due to large size of dihydropyrimidinone compounds towards the supercage dimension of Y zeolite. In addition, the catalyst was recovered and reused for several times without efficient loss in catalytic activity.     

Polystyryl-supported TBD as an efficient and reusable catalyst under solvent-free conditions

Polystyryl supported-TBD (PSTBD) is an efficient and reusable heterogeneous basic catalyst under solvent-free conditions for a variety of organic transformations such as 1,2-epoxide ring-opening, aldol-type condensation and Michael addition.     

Flower-shaped ZnO nanoparticles as an efficient, heterogeneous and reusable catalyst in the synthesis of N-arylhomophthalimides and benzannelated isoquinolinones

A simple and green protocol, developed utilizing an efficient, heterogeneous and recyclable catalyst, i.e. zinc oxide nanoparticles (ZnO NPs)-mediated synthesis of N-arylhomophthalimides and benzannelated isoquinolinones, is reported. The structures of the desired products were characterized by FTIR, ¹H NMR, ¹³C NMR, and HRMS techniques. The ZnO NPs exhibited excellent catalytic activity and the proposed methodology is capable of providing the desired products in good yield and purity.     

Scandium(III) triflate as an efficient and reusable catalyst for synthesis of 1,5-benzodiazepine derivatives

2,3-Dihydro-1H-1,5-benzodiazepines have been synthesized in solvent-free conditions in excellent yield from o-phenylenediamines and ketones in the presence of a catalytic amount of Sc(OTf)₃. This method is a very easy, rapid, and high yielding reaction for the synthesis of 1,5-benzodiazepine derivatives.     

Ligand free,highly efficient synthesis of diaryl ether over copper fluorapatite as heterogeneous reusable catalyst

A novel ligand-free, highly efficient, and an inexpensive method has been developed by using ecofriendly, heterogeneous reusable copper fluorapatite (CuFAP) catalyst for the synthesis of diaryl ethers from the cross coupling reaction of the various substituted aryl halides (fluoride, chloride, bromide, and iodide) with the potassium salts of various substituted phenols in the presence of N-methyl 2-pyrrolidone (NMP) as a solvent at 120 °C. The protocol obtained the corresponding cross coupling products in good to excellent yield. The CuFAP catalyst was recovered by simple filtration from the reaction mixture and reused several times without the loss of catalytic activity.     

Covalently anchored sulfonic acid on silica gel （SiO2-R-SO3H） as an efficient and reusable heterogeneous catalyst for the one-pot synthesis of 1,8-dioxooctahydroxanthenes under solvent-free conditions

A highly efficient one-pot synthesis of 1,8-dioxooctahydroxanthenes under solvent-free conditions catalyzed by sulfonic acid covalently anchored onto the surface of silica gel is reported.All types of aldehydes,including aromatic,unsaturated,and heterocyclic,are used.The silica gel/sulfonic acid catalyst (SiO2-R-SO3H) is completely heterogeneous and can be recycled.     

One-pot synthesis of dihydropyrimidones using silica-supported heteropoly acid as an efficient and reusable catalyst: Improved protocol conditions for the Biginelli reaction

An efficient synthesis of 3,4-dihydropyrimidinones or thiones (DHPMs) is described, using silica-supported heteropoly acid H₃PW₁₂O₄₀/SiO₂ (PW/SiO₂) for the first time as the catalyst from an aldehyde, β-keto ester and urea or thiourea in acetonitrile. Compared to the classical Biginelli reaction conditions, this method consistently has the advantage of excellent yields, mild reaction conditions, ease of workup, survival of different functional groups, and short reaction times.     

One-pot synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles by zinc oxide as efficient and reusable catalyst

Abstract  

ZnO is an efficient, readily available, and reusable catalyst for the one-pot synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles. This procedure is very simple and affords excellent yields.