CuO‐CeO2 Nanocomposite: A Highly Efficient Recyclable Catalyst for the Green Synthesis of 1,8‐Dioxooctahydroxanthenes in Water

CuO‐CeO₂ nanocomposite is reported as a highly efficient and recyclable catalyst for the green synthesis of 1,8‐dioxooctahydroxanthenes in water. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any losing of its efficiency.     

One‐pot,Green and Efficient Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones or Thiones Catalyzed by Citric Acid

One‐pot three‐component condensation of ethyl acetoacetate, aldehyde and urea or thiourea in refluxing ethanol in the presence of catalytic amounts of citric acid afforded the corresponding 3,4‐dihydropyrimidin‐2(1H)‐ones/thiones in high yields. The catalyst is reusable and can be applied several times without any decrease in product yield.     

TiO2 as a Reusable Catalyst for the One‐Pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones under Solvent‐Free Conditions

An efficient solvent‐free method for the synthesis of various 3,4‐dihydropyrimidin‐2(1H)‐ones using TiO₂ as a recyclable heterogeneous catalyst is described. Compared to known methods, satisfactory results are obtained with excellent yields, short reaction times, and simplicity in the experimental procedure.     

Nickel Chloride Hexahydrate Catalyzed Multicomponent Biginelli's Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐Ones and Thiones

An efficient protocol is reported for the one‐pot three‐component Bignelli synthesis of a series of 3,4‐dihydropyrimidine‐2(1H )‐ones and thiones in good yields (66–90%) from the aldehydes (4‐benzyloxybenzaldehyde, 5‐bromovanilin, 4‐formyl‐1‐cyclohexene, and trans‐cinnamaldehyde), β‐keto esters (ethyl acetoacetate, allyl acetoacetate, and t‐butyl acetoacetate), and urea/thiourea in ethanol, using nickel chloride hexahydrate as a catalyst.     

Xanthan Sulfuric Acid as an Efficient Biodegradable and Recyclable Catalyst for the One‐Pot Synthesis of α‐Amino Phosphonates

A convenient and efficient procedure for the synthesis of α‐amino phosphonates by a one‐pot, three‐component condensation of aldehydes, amine, and diethyl phosphite in the presence of xanthan sulfuric acid as a bio‐supported catalyst under solvent‐free conditions has been developed. A wide range of α‐amino phosphonates have been obtained in high to excellent yields. Furthermore, the catalyst can be recovered simply and reused several times in subsequent reactions.     

Silica Nanoparticles as a Highly Efficient Catalyst for the One‐Pot Synthesis of 2‐Hydroxyacetamide Derivatives from Isocyanides and Electron‐Poor Aromatic Aldehydes

Reaction of an isocyanide with an electron‐poor aromatic aldehyde in the presence of silica nanoparticles (silica NP; ca. 42 nm) proceeds smoothly at room temperature to afford 2‐hydroxyacetamide derivatives in high yields (Scheme 1 and Table 1).     

One‐pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones Catalysed by Cupric Acetate under Solvent‐free Conditions

A solvent‐free synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones from aromatic aldehydes, β‐keto ester/acetyl acetone and urea catalysed by cupric acetate under thermal condition is reported as a simple and an efficient protocol. Compared with classical Biginelli reaction reported in 1893, this new method provides much improved modification in terms of yield and reaction time. The usage of milder catalyst, environmental friendly procedures and excellent yields within a very short time (5–15 min) are the advantages of the method in which the involvement of solvent‐free condition adds an edge to the method. Thus, the efficiency of the protocol enabled the rapid synthesis of 3,4‐dihydropyrimidin‐2(1H)‐one derivatives in a short duration.     

A Green Approach for the One‐Pot,Three‐Component Synthesis of 2‐Arylpyrroloacridin‐1(2H)‐Ones using Lactic Acid as a Bio‐based Catalyst under Solvent‐Free Conditions

A facile and benign synthetic strategy is proposed for the synthesis of 2‐arylpyrroloacridin‐1(2H )‐ones via a lactic acid‐catalyzed three‐component reaction of dimedone, various anilines, and isatins under solvent‐free conditions. Avoidance of hazardous organic solvents, the use of a one‐pot multicomponent procedure for the synthesis of 2‐arylpyrroloacridin‐1(2H )‐ones, operational simplicity, no need for column chromatography, lactic acid utilization as a bio‐based organic compound, reusability, homogeneity, and commercial availability of the catalyst, and superior synthetic performance are some important aspects of this methodology to access a series of pyrroloacridine motifs with potentially biological scaffolds.     

Zirconyl Chloride (= Dichlorooxozirconium) as an Efficient Catalyst for One‐Pot Multicomponent Synthesis of Homoallylic Amines

Zirconyl chloride (ZrOCl₂) catalyzes efficiently the one‐pot three component reactions of aldehydes, amines, and allyltributylstannane at room temperature to furnish the corresponding homoallylic amines in short reaction times and in excellent yields.     

One—Pot Synthese of 3,4—Dihydropyrimidine—2（1H）—thiones Catalyzed by La（OTf）3

A general and practical procedure for the syntheses of 3,4-di-hydropyrimidine-2(1H)-thiones by a one-pot condensation of aldehyde,β-ketoester or β-diketone and thiourea using La(OTf)3 as the catalyst is described.Mild reaction conditions,excellent yields as well as the environmentally friendly character of La(OTf)3 make it an important alternative to the classic acid-catalyzed Biginelli‘s reaction.     

One‐Step Synthesis of 1‐(4,5‐Diphenylpyrimidin‐2‐yl)thiourea

A simple and straightforward methodology toward the synthesis of novel 1‐(4,5‐diphenylpyrimidin‐2‐yl)thiourea has been developed by a one‐step reaction of isoflavones with amidinothiourea. A series of 16 new compounds was synthesized. All compounds were characterized by FT‐IR, NMR, and elemental analysis. The structure of a typical compound was established by X‐ray diffraction. A variety of substrates can participate in the process with good yields and high purities, making this methodology suitable for library synthesis in drug discovery.     

Zn3(BTC)2 as a Highly Efficient Reusable Catalyst for the Synthesis of 2‐Aryl‐1H‐Benzimidazole

Zn₃(BTC)₂ metal‐organic frameworks as recyclable and heterogeneous catalysts were effectively used to catalyze the synthesis of benzimidazole derivatives from o‐phenylendiamine and aldehydes in ethanol. This method provides 2‐aryl‐1H‐benzimidazoles in good to excellent yields with little catalyst loading. The catalyst was characterized using different techniques such as X‐ray diffraction (XRD), energy dispersive X‐ray (EDX) analysis, scanning electron microscopy (SEM), and Fourier transform infrared (FT‐IR) spectroscopy.     

One‐Pot Synthesis of N,N‐Disubstituted (Z)‐4‐(Halomethylidene)‐4H‐3,1‐benzothiazin‐2‐amines from 2‐(2,2‐Dihaloethenyl)phenyl Isothiocyanates and Secondary Amines

We have developed a one‐pot procedure for the preparation of N,N‐disubstituted (Z)‐4‐(halomethylidene)‐4H‐3,1‐benzothiazin‐2‐amines 3 from 2‐(2,2‐dihaloethenyl)phenyl isothiocyanates 1 , easily accessible from known 2‐(2,2‐dihaloethenyl)benzenamines by a three‐step sequence, and secondary amines. Thus, the isothiocyanates 1 react with secondary amines to afford the corresponding thiourea derivatives, of which the treatment with NaH provides the desired products.     

CoCl_2·6H_2O or LaCl_3·7H_2O Catalyzed Biginelli Reaction. One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1 H)-ones

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Three Component Reaction: An Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones and Thiones Using Heterogeneous Catalyst

Fluoroboric acid supported on silica gel (HBF₄‐SiO₂) catalyzes efficiently the three component condensation of an aldehyde, a 1,3‐dicarbonyl compound and urea or thiourea to afford the corresponding 3,4‐dihydropyrimidin‐ 2(1H)‐ones and thiones in high yields. The ambient conditions, fast reaction rates, and excellent product yields are the important characteristics of this reaction.     

NaY Zeolite Functionalized by Sulfamic Acid/Cu(OAc)2 as a Novel and Reusable Heterogeneous Hybrid Catalyst in Efficient Synthesis of Bis,Tris, and Tetrakis(indolyl)methanes, 3,4‐Dihydropyrimidin‐2(1H)‐ones,and 2‐Aryl‐1H‐benzothiazoles

An efficient acid‐catalyzed synthesis of some bis, tris, and tetrakis(indolyl)methanes, 3,4‐dihydropyrimidin‐2(1H )‐ones, and 2‐aryl‐1H ‐benzothiazoles is reported using NaY zeolite functionalized by sulfamic acid/Cu(OAc )₂ (NaY zeolite‐NHSO₃H /Cu(OAc )₂) in excellent yield. The heterogeneous catalyst has a simple work‐up procedure and could be recycled and reused for six reaction cycles.     

Highly Efficient One-Pot Synthesis of 2-Arylmethyl N-Substituted Anilines via Yb（OTf）3 Catalyzed Three-Component Reaction

An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under mild conditions to afford the corresponding 2-arylmethyl N-substituted anilines in good yields. In addition, the catalyst was easily recovered and could be reused for at least four cycles without any loss of activity.     

A Novel and Efficient Catalyst to One‐Pot Synthesis of 2‐Amino‐4H‐Chromenes by Methanesulfonic Acid

Methanesulfonic acid efficiently catalyzes the one‐pot, three component reaction of an aromatic aldehyde, malonitrile and α or β‐naphthol to yield 2‐amino‐4H‐chromenes in very good yields.     

Efficient Synthesis of Trialkyl 3‐Phenylbuta‐1,3‐diene‐1,2,4‐tricarboxylates by a Novel One‐Pot Multicomponent Reaction

Alkyl 2‐nitroacetates 2 react with alkyl phenylpropiolates 1 in the presence of Ph₃P in a mechanistically novel reaction to afford trialkyl 3‐phenylbuta‐1,3‐diene‐1,2,4‐tricarboxylates in yields of 60–80% under neutral conditions.