Silica supported perchloric acid （HClO4-SiO2）： A mild,reusable and highly efficient heterogeneous catalyst for the synthesis of amidoalkyl naphthols

An efficient and direct procedure has been developed for the preparation of amidoalkyl naphthols by a one-pot condensation of aryl aldehydes, 2-naphthol and urea or amides, in the presence of HClO4-SiO2 as a heterogeneous catalyst. The reactions were carried out under reflux and solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, easy work-up and ecofriendly reaction condition. The catalyst is easily prepared, stable, reusable and efficient under the reaction conditions.     

Silica supported perchloric acid (HClO4-SiO2): an efficient and recyclable heterogeneous catalyst for the one-pot synthesis of amidoalkyl naphthols

An efficient and direct protocol for the preparation of amidoalkyl naphthols employing a multi-component and one-pot condensation reaction of 2-naphthol, aromatic aldehydes, and acetonitrile or acetamide in the presence of silica supported perchloric acid under solvent, solvent-free, and microwave irradiation conditions is described. The present protocol with HClO₄-SiO₂ catalyst is superior to the recently reported catalytic methods. It is noteworthy that 1-amidomethyl-2-naphthols can be converted into important ‘drug like’ 1-aminomethyl-2-naphthol derivatives by amide hydrolysis.     

MCM-41 anchored sulfonic acid (MCM-41-R-SO3H): A mild, reusable and highly efficient heterogeneous catalyst for the Biginelli reaction

An efficient three-component synthesis of 3A-dihydropyrimidinones using MCM-41 anchored sulfonic acid (MCM-41-R-SO3H) as a mild, heterogeneous catalyst for Biginelli reaction in CH3CN under reflux condition is described.     

Aluminatesulfonic acid: Novel and recyclable nanocatalyst for efficient synthesis of aminoalkyl naphthols and amidoalkyl naphthols

In this study, an efficient, mild, and eco-friendly procedure is developed for the preparation of 1-amidoalkyl-2-naphthols and Betti bases from one-pot three-component condensation of aldehydes, 2-naphthol, and nitrogen sources (amides for amidoalkyl naphthols and amine for Betti bases) in the presence of aluminatesulfonic acid nanoparticles (ASA NPs) as recoverable catalyst under solvent-free conditions. ASA NPs were prepared by a simple reaction of net chlorosulfonic acid and sodium aluminate in high purity. ASA NPs were characterized by Fourier transform IR, X-ray powder diffraction, transmission electron microscopy, energy-dispersive X-ray, thermal gravimetric analysis, and UV diffusion/reflectance techniques. On the basis of the thermal gravimetric analysis and some activation parameters evaluated from decomposition thermal steps using Coats–Redfern model, the catalyst showed high thermal stability. High yields, short reaction time, easy workup, inexpensive, and reusability of the catalyst are advantages of this method.     

Silica supported perchloric acid (HClO4-SiO2): a green,reusable, and highly efficient heterogeneous catalyst for the synthesis of thioethers under solvent-free conditions at room temperature

Abstract

A highly efficient and clean procedure is described for the synthesis of thioethers with excellent yields under solvent-free conditions at room temperature using a catalytic amount of HClO₄-SiO₂. The catalyst is easily prepared, stable, and reusable without much loss of catalytic activity, and is efficient under the reaction conditions.     

MCM-41 anchored sulfonic acid （MCM-41-R-SO3H）： A mild,reusable and highly efficient heterogeneous catalyst for the Biginelli reaction

An efficient three-component synthesis of 3,4-dihydropyrimidinones using MCM-41 anchored sulfonic acid （MCM-41-R-SO3H） as a mild, heterogeneous catalyst for Biginelli reaction in CH3CN under reflux condition is described.     

Microwave assisted highly efficient one-pot multi-component synthesis of novel 2-(tetrasubstituted-1H-pyrrol-3-yl)-4H-chroman-4-ones catalyzed by heterogeneous reusable silica gel supported polyphosphoric acid (PPA/SiO2)

A solvent-free, eco-friendly and facile approach for the synthesis of highly functionalized tetrasubstituted pyrroles has been reported through one-pot four-component reaction of aldehyde, amine, nitroalkane and 1,3-diketone using silica gel supported polyphosphoric acid (PPA–SiO₂) under microwave condition. The reaction occured through the in situ formation of β-keto enamine and nitrostyrene analog following Michael addition and finally intramolecular annulation affording the products in good yields. The key features of the present method include clean reaction, mild conditions, low catalyst loading, straightforward, high to excellent yields, short reaction time, avoiding use of harmful metal catalyst and organic solvent, environmentally friendly compared to the existing methods, recovery and reusability of catalyst and easy workup procedure.     

Nano-sulfated zirconia as an efficient, recyclable and environmentally benign catalyst for one-pot three component synthesis of amidoalkyl naphthols

One pot synthesis of amidoalkyl naphthols by reaction of aromatic aldehydes,2-naphthol and amide/urea using nano-sulfated zirconia as a catalyst is reported.The reaction was carried out under solvent-free conditions.The method gave good yields of amidoalkyl naphthols in short reaction time.The catalyst is recycled for five consecutive times without loss of activity.     

SnCl2/nano SiO2：A green and reusable heterogeneous catalyst for the synthesis of polyfunctionalized 4H-pyrans

A highly efficient and general method for the synthesis of polyfunctionalized 4H-pyrans is established through a one-pot multicomponent cyclocondensation of aromatic aldehydes with CH acids, malononitrile and ethyl acetoacetate using nano silica supported tin (Ⅱ) chloride as a catalyst. In this method SnCl2/nano SiO2 was used as green and reusable catalyst. Excellent yields, short reaction times, simple workup, and inexpensiveness and commercially availability of the catalyst are the advantages of this method.     

活性炭负载硫化锡纳米颗粒作为高效可重复使用Lewis酸催化剂催化三组分一锅法合成4H-吡喃[2,3-c]吡唑衍生物(英文)

Tin sulfide nanoparticles(SnS -NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon(AC) and were investigated using field-emission scanning electron mi-croscopy(FE-SEM), transmission electron microscopy(TEM), X-ray diffraction, reflective ultravio-let-visible spectrophotometry, and spectrofluorimetry. Calculations based on the SEM and TEM images showed that the sizes of the SnS -NPs immobilized on the AC were 30–70 nm. The prepared nanocomposite was used as a heterogeneous Lewis acid catalyst for the three-components one-pot synthesis of 4H-pyrano[2,3-c]pyrazole derivatives in ethanol at 80 ℃. The reactions were efficiently performed in the presence of the prepared catalyst in short reaction times, and gave the desired products in high yields. This catalyst can be easily recovered by simple filtration and recycled up to eight consecutive times without significant loss of its efficiency.     

Tin sulfide nanoparticles supported on activated carbon as an efficient and reusable Lewis acid catalyst for three-component one-pot synthesis of 4H-pyrano[2,3-c]pyrazole derivatives

Tin sulfide nanoparticles (SnS‐NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon (AC) and were investigated using field‐emission scanning electron mi‐croscop...     

Silica-supported Preyssler nano particles: a green,reusable and highly efficient heterogeneous catalyst for the synthesis of carbamatoalkyl naphthols

Abstract

An efficient and green procedure has been developed for the preparation of carbamatoalkyl naphthols by the one-pot condensation of aryl aldehydes, β-naphthol, and methyl carbamate in the presence of silica-supported Preyssler nano particles as a heterogeneous catalyst under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, easy work-up, and eco-friendly reaction conditions. The catalyst is easily prepared, stable, reusable, and efficient under the reaction conditions.     

Brønsted acidic ionic liquid as an efficient and reusable catalyst for one-pot synthesis of 1-amidoalkyl 2-naphthols under solvent-free conditions

A mild and efficient method has been developed for the preparation of amidoalkyl naphthols from condensation of aldehydes with amides or urea and 2-naphthol in the presence of a catalytic amount of Brønsted acidic ionic liquid ([TEBSA][HSO₄]) under thermal solvent-free conditions. High yields, short reaction time, easy work-up and reusability of the catalyst are advantages of this procedure.     

Silica supported ammonium dihydrogen phosphate (NH4H2PO4/SiO2):A mild,reusable and highly efficient heterogeneous catalyst for the synthesis of 14-aryl-14-H-dibenzo[a,j]xanthenes

Silica supported ammonium dihydrogen phosphate (NH₄H₂PO₄/SiO₂) is found to be a recyclable heterogeneous catalyst for a rapid and efficient synthesis of various aryl-14-H-dibenzo[a,j]xanthenes with excellent yields under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, short reaction times and milder conditions.     

Silica-supported polyphosphoric acid (PPA-SiO2): An efficient and reusable heterogeneous catalyst for ecofriendly organic synthesis

This review discusses the advances in the use of silica-supported polyphosphoric acid (PPA-SiO₂) as a green and reusable heterogeneous catalyst in the preparation of various organic compounds and pharmaceutical intermediates. PPA-SiO₂ could be recovered and reused several times without significant loss of their efficiency. In this review, we attempt to give an overview of the applications of PPA-SiO₂ as a catalyst in condensation, cyclization, and addition reactions for the preparation of various organic compounds.     

HClO4-SiO2 as a new, highly efficient, inexpensive and reusable catalyst for N-tert-butoxycarbonylation of amines

Perchloric acid adsorbed on silica-gel (HClO4-SiO2) was found to be a new, highly efficient, inexpensive and reusable catalyst for chemoselective N-tert-butoxycarbonylation of amines at room temperature and under solvent-free conditions.     

N-Sulfonic acid poly(4-vinylpyridinium) chloride as a highly effcient and reusable catalyst for the Biginelli reaction简

A mild, simple and efficient procedure for the preparation of 3,4-dihydropyrimidin-2（1H）-ones and -thiones is described using N-sulfonic acid poly（4-vinylpyridinium） chloride （NSPVPC） as a heterogeneous and efficient catalyst under solvent-free conditions. Simple methodologies, easy work-up procedure, easy preparation of the catalyst, excellent yields and very short reaction times are among the other advantages of this work. Further, the catalyst can be reused and recovered for several times without significant decrease in its activity.     

Scolecite as an efficient heterogeneous catalyst for the synthesis of 2,4,5-triarylimidazoles

Natural scolecite has been found as an effective catalyst for the one-pot synthesis of 2,4,5-triarylimidazole derivatives via a three component reaction using benzil or benzoin, aldehydes and ammonium acetate. This method provides several advantages such as being environmentally benign, reusable, possessing high yields with increased variations of the substituents in the product and preparative simplicity.      

Fe(HSO4)3: An efficient, heterogeneous and reusable catalyst for the synthesis of 14-aryl- or alkyi-14H-dibenzo[a.j]xanthenes

Fe(HSO4)3 has been used as an efficient and reeyclable catalyst for the one-pot synthesis of 14-aryl- or alkyl-14H-dibenzo[a,j]xanthene derivatives by the reaction of 2-naphtol and aldehydes. Different types of aromatic and aliphatic aldehydes are used in the reaction and in all cases the products were obtained in good to excellent yields.