Facile one-pot synthesis of 5-amino-1H-pyrazole-4-carbonitriles using alumina–silica-supported MnO2 as recyclable catalyst in water

Research on Chemical Intermediates - A novel, facile, one-pot, multicomponent protocol for the synthesis of 5-amino-1H-pyrazole-4-carbonitrile derivatives has been developed using...     

Synthesis of 9-oxiranyl-9H-purine derivatives in β-cyclodextrin cavity

An efficient and mild method has been developed for the preparation of 9-oxiranyl-9H-purine derivatives. This reaction proceeds smoothly in β-cyclodextrin cavity at room temperature, giving good to excellent yields.     

A novel highly stereoselective multi-component synthesis of N-substituted β-amino ketone derivatives using copper(II) phthalocyanine as reusable catalyst

Stereoselective synthesis of N-substituted β-amino ketone derivatives with substituents include one or two polar hetero atoms on benzene rings in many cases has been achieved by a one-pot multi-component process using copper(II) phthalocyanine as catalyst. The new process is suitable for the inclusion of a wide variety of substrates for the construction of highly functionalized Mannich-type structural scaffolds. The catalyst used is recycled and reused for repeating the reactions.     

Tandem supramolecular synthesis of substituted 2-aryl-2,3-dihydroquinazolin-4(1H)-ones in the presence of β-cyclodextrin in water

Substituted 2-aryl-2,3-dihydroquinazolin-4(1H)-ones were prepared for the first time in water under neutral conditions by the reaction of aniline, isatoic anhydride, and aldehyde mediated by β-cyclodextrin in good yields. β-Cyclodextrin can be recovered and reused with a little loss of catalytic activity.     

One-pot synthesis of β-acetamido-β-arylpropiophenone employing trifluoroacetic acid as an efficient catalyst

Trifluoroacetic acid as an efficient catalyst promoting the Dakin–West reaction at ambient temperature is reported for the first time in this paper. A few efficacious auxiliary catalysts were also developed for the Dakin–West reaction. A variety of substituted aryl aldehydes and aryl ketones were found to be applicable to the preparation of some new β-acetamido-β-arylpropiophenones. This procedure has several advantages such as high yields, short reaction time, and smaller amount (0.30 mol%) of catalyst.     

Efficient synthesis of 1-carbamatoalkyl-2-naphthols using Brønsted acidic ionic liquid as reusable catalyst

Efficient synthesis of 1-carbamatoalkyl-2-naphthols can be carried out in the presence of halogen-free Brønsted acidic ionic liquid, synthesized from 1,4-diaza-bicyclo[2.2.2]octane (DABCO) and 1,4-butanesulfonate. A wide range of aldehydes and carbamates easily undergo condensation with 2-naphthol to afford the desired products in good to excellent yields. The present methodology offers several advantages, such as a simple work-up procedure and short reaction times. The catalyst can be recycled and reused without substantial reduction in catalytic activities.     

One-pot synthesis of 1,2,3-triazoles from boronic acids in water using Cu(II)-β-cyclodextrin complex as a nanocatalyst

We report here the one-pot synthesis of 1,2,3-triazoles of arylboronic acids in water. An efficient method has been developed for the synthesis of 1,2,3-triazoles via a one-pot reaction of an arylboronic acid with sodium azide in the presence of Cu(2)-β-CD (CD = Cyclodextrin) as a nanocatalyst in water followed by a click cyclization reaction with an alkyne at room temperature in air without any additives. This method is simple, rapid, and high yielding.     

Mechanism into selective oxidation of cinnamaldehyde using β-cyclodextrin polymer as phase-transfer catalyst

Selective oxidation of cinnamaldehyde to benzaldehyde in the presence of bicarbonate and hydrogen peroxide and catalyzed by β-cyclodextrin polymer (β-CDP) was investigated. β-CDP was utilized as the phase-transfer catalyst in this study. The immobilized β-cyclodextrin possessing a hydrophobic host cavity was found to be efficient as mass-transfer promoters for the oxidation of cinnamaldehyde. Benzaldehyde could be obtained in 63% yield under optimal reaction conditions. The results indicate the complex formed between cinnamaldehyde and β-CDP via the intermolecular weak interactions, e.g., hydrogen bond was the reason why the conversion and selectivity could be significantly promoted. Finally, the reusability of the catalyst was also evaluated. Its catalytic activity remained unchanged even after recycled for six times, which suggests it is an efficient catalyst for oxidation of cinnamaldehyde.     

Regioselective synthesis of polysubstituted 4H-thiopyrans from β-oxodithioesters

A simple and efficient method for the synthesis of polyfunctionalized 4H-thiopyrans by highly regioselective cyclocondensation of β-oxodithioesters with 1,1,3-trialkyl or aryl substituted prop-2-yn-1-ols using BF₃·Et₂O as the catalyst is described.     

One-pot synthesis of 2,3-disubstituted benzofurans from 2-chlorophenols using palladium–dihydroxyterphenylphosphine catalyst

2,3-Disubstituted benzofurans possessing 2-hydroxyphenyl moiety at the C-3 position were synthesized from readily available 2-chlorophenols and terminal alkynes by hydroxy-directed ortho-Sonogashira coupling and subsequent oxypalladation/reductive elimination, using Pd-dihydroxyterphenylphosphine catalyst. The catalyst accelerates not only the Sonogashira coupling but also the introduction of 2-hydroxyphenyl group at the C-3 position of benzofuran.     

Solvent-free multicomponent synthesis of pyranopyrazoles: per-6-amino-β-cyclodextrin as a remarkable catalyst and host

A simple, green and efficient protocol is developed with per-6-amino-β-cyclodextrin (per-6-ABCD) which acts simultaneously as a supramolecular host and as an efficient solid base catalyst for the solvent-free syntheses of various dihydropyrano[2,3-c]pyrazole derivatives involving a four-component reaction. This atom-economical protocol, reported for the first time with ketones also, includes a much milder procedure, does not involve any tedious work-up or purification, avoids hazardous reagents/byproducts and results in near quantitative yields. The catalyst can be reused at least six times without any change in its catalytic activity.     

Novel and efficient supramolecular synthesis of pyrroles in the presence of β-cyclodextrin in water

A simple and efficient synthesis of highly substituted pyrroles was achieved in water medium via multi-component strategy, using amine,DMAD/DEAD as well as phenacyl bromide catalyzed by β-CD.Utilizing this protocol various pyrrole derivatives were synthesized in good to excellent yields.     

One-pot synthesis of benzoquinoline and coumarin derivatives using Meldrum’s acid in three-component reactions

A series of 1-aryl-1,2-dihydrobenzo[f]quinolin-3(4H)-one derivatives and 4-aryl-7,7-dimethyl-5-oxo-3,4,5,6,7,8-hexahydrocoumarin derivatives have been synthesized by one-pot multicomponent reaction of Meldrum’s acid with benzaldehyde, naphthalene-2-amine, or cyclohexanedione in PEG-400. The method has the advantages of mild reaction conditions, good yields, and easy processing, and is environmentally benign.     

β-Cyclodextrin as an efficient catalyst for the one-pot synthesis of tetrahydrobenzo[b]pyran derivatives in water

Various 4H-benzo[b]pyran derivatives were synthesized via a one-pot three-component condensation of arylaldehyde, malononitrile and dimedone in water using β-cyclodextrin (β-CD) as an efficient catalyst. This method provides several advantages, including mild reaction conditions, operational simplicity, high yields and minimal pollution of the environment.     

Distereoselective one-pot synthesis of pyrimidopyrimidines using sulfated tin oxide as a reusable catalyst： An extension of Biginelli-type reaction

The Biginelli-type compounds 4,5,8a-triarylhexahydropyrimido[4,5-d]pyrimidine-2,7（1H,3H）-diones were synthesized by a one-pot three-component reaction using sulfated tin oxide as a reusable catalyst. This method has the advantages of high yields, short reaction time, simple starting materials and reusability of catalyst for several times.     

Synthesis of thiazole derivatives using magnetic nano zirconia–sulfuric acid as an efficient and recyclable catalyst in water

Russian Journal of General Chemistry - Fe3O4 magnetic core covered by zirconia shell bearing sulfonic acid groups (Fe3O4@ZrO2–SO3H) was prepared and used as an efficient acidic catalyst in...     

Efficient one-pot synthesis of β-phosphono malonates and 2-amino-4H-chromen-4-ylphosphonate derivatives by ethylenediamine diacetate-catalyzed three-component reactions

One-pot three-component reactions of arylaldehyde or salicylaldehyde with malononitrile (or ethylcyanoacetate) and triethyl phosphite are carried out in the presence of ethylenediamine diacetate (EDDA) as a catalyst for the synthesis of biologically interesting β-phosphono malonates and 2-amino-4H-chromen-4-ylphosphonate derivatives. The value of this method lies in its mild reaction catalyst and conditions, good yields, and ease of handling.