Indion 190 resin: efficient,environmentally friendly,and reusable catalyst for synthesis of benzimidazoles,benzoxazoles, and benzothiazoles

Abstract

An efficient and mild protocol has been developed for the preparation of benzimidazoles, benzoxazoles, and benzothiazoles from reactions of aldehydes with o-substituted aminoaromatics in the presence of catalytic amount of Indion 190 resin. Short reaction time, ambient conditions, simple work-up procedure, high yield, easy availability, reusability, and use of an eco-friendly catalyst are some of the striking features of the present protocol.     

Tungstate sulfuric acid as an efficient catalyst for the synthesis of benzoxazoles and benzothiazoles under solvent-free conditions

Tungstate sulfuric acid (TSA) has been found to be an efficient and reusable catalyst for the synthesis of benzoxazole and benzothiazole derivatives via reactions of orthoesters with o-aminophenols or o-aminothiophenols in high yields.     

Protic guanidinium ionic liquid as a green and highly efficient catalyst for the synthesis of functionalized spirochromenes under solvent-free conditions

A simple and efficient method for the synthesis of functionalized spirochromenes is explained using protic guanidinium ionic liquid as a catalyst under solvent-free conditions at room temperature. This procedure is simple, clean, and excellent yields are obtained in short reaction times.     

Xanthan sulfuric acid: An efficient and biodegradable solid acid catalyst for the synthesis of bis(indolyl)methanes under solvent-free conditions

Xanthan sulfuric acid (XSA) is found to be an efficient catalyst for the electrophilic substitution reaction of indole with aromatic aldehydes to afford the corresponding bis(indolyl)methanes at room temperature under solvent-free conditions. The catalyst was characterized for the first time with the help of powder XRD, SEM–EDX and DSC–TGA. The attractive features of this green, new methodology are excellent yield of products, clean reaction profile, reusability of the catalyst, energy sustainable protocol, simple experimental and easier work-up procedures.     

Wet 2,4,6-trichloro-1,3,5-triazine(TCT)as an efficient catalyst for the synthesis of 2,4,6-triarylpyridines under solvent-free conditions

<正>An efficient one-pot synthesis of 2,4,6-triarylpyridines has been described.This involves the three-component reaction of aldehydes,ketones and ammonium acetate in the presence of a catalytic amount of wet 2,4,6-trichloro-1,3,5-triazine(TCT) under solvent-free condition at 130℃.     

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.     

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.      

1,3-Dibromo 5,5-dimethylhydantoin (DBH):A novel and efficient catalyst for the synthesis of 14-aryl-14H-dibenzo[a,j] xanthenes under solvent-free conditions

An atom-efficient and environment-friendly approach for the synthesis of aryl-14H-dibenzo[a,j]xanthenes (3a–o) via the one-pot reaction of β-naphthol and aryl aldehydes (1) catalyzed by DBH has been developed. The present approach offers several advantages such as reduced reaction times, moderate temperature, higher yields, solvent free, eco-friendly reaction condition, easy purification and economic availability of the catalyst.     

Selenonium ionic liquid as an efficient catalyst for the synthesis of thioacetals under solvent-free conditions

Acidic ionic liquid butyl ethyl phenyl selenonium tetrafluoroborate, [BEPSe]BF₄, was successfully employed as a catalyst for the synthesis of several dithioacetals in the absence of a solvent. The method is general and selectively afforded thioacetals derived from aldehydes and ketones in good yields.     

Tetraethylammonium hydrogen carbonate: A cheap,efficient, and recyclable catalyst for transesterification reactions under solvent-free conditions

Tetraethylammonium hydrogen carbonate (TEAHC) was proven to be an efficient catalyst for transesterification reactions in the absence of solvent. The reaction between isopropenyl or ethyl acetate and an alcohol (not efficient in the absence of catalyst) was induced by the presence of TEAHC, which seems to assist the proton transfer from the alcohol to the ester, yielding the corresponding acetate in very good yields in the absence of any solvent. Moreover, the TEAHC can be recycled several times without significant loss in activity.     

Zirconium(IV) 4-sulphophenylethyliminobismethylphosphonate as an efficient and reusable catalyst for one-pot synthesis of 3,4-dihydropyrimidones under solvent-free conditions

Zirconium(IV) 4-sulphophenylethyliminobismethylphosphonate (ZSBEDP) was prepared and characterised by elemental analysis, IR, TG-DSC, and XRD. ZSBEDP was found to be an efficient catalyst for the Biginelli reaction of aromatic aldehyde, ethyl acetoacetate, and urea or thiourea under solvent-free conditions so as to give 3,4-dihydropyrimidones in good to excellent yields. The catalyst can be separated by simple filtration and reused without significant loss of its catalytic activity.     

KSF supported 10-molybdo-2-vanadophosphoric acid as an efficient and reusable catalyst for one-pot synthesis of 2,4,5-trisubstituted imidazole derivatives under solvent-free condition

The one-pot three-component cyclocondensation has been developed involving the reaction of benzil with an aromatic aldehydes and ammonium acetate under thermal solvent-free conditions in the presence of a KSF supported 10-molybdo-2-vanadophosphoric acid catalyst. 10-Molybdo-2-vanadophosphoric acid was immobilized on KSF with a 20% loading, which showed the highest catalytic activity. The catalyst was fully characterized using FT-IR spectroscopy, thermal analysis, XRD and SEM analysis techniques. There are several distinct advantages to this protocol, including high yields, short reaction time, operational simplicity and a recyclable catalyst with a facile work-up procedure.     

聚乙烯基吡啶高氯酸盐作为高效固体酸催化剂在无溶剂条件下催化醛化学选择性制备二乙酸盐简

Poly(4-vinylpyridinium) perchlorate has been used as a supported, recyclable, environmentally-benign catalyst for the formation of acylals from aliphatic and aromatic aldehydes in good to excellent yields under solvent-free conditions. Notably, the reaction conditions were tolerant of ketones. This methodology offers several distinct advantages, including its operational simplicity and high product yield, as well as being green in terms of avoiding the use of toxic catalysts and solvents. Furthermore, the catalyst can be recovered and reused several times without any loss in its activity.     

Greener approach: Ionic liquid [Et3NH][HSO4]-catalyzed multicomponent synthesis of 4-arylidene-2-phenyl-5(4H)oxazolones under solvent-free condition

We have developed simple, greener, safer multicomponent synthesis series of 4-arylidene-2-phenyl-5(4H) oxazolones 4(a-r) catalyzed by Bronsted acid ionic liquid as triethylammonium hydrogen sulfate [Et₃NH][HSO₄] and catalytic amount of acetic anhydride and sodium acetate with excellent yields (90–99%). The protocol offers economical, environmentally benign, solvent-free conditions, and recycle–reuse of the catalyst and easily available starting as benzoyl chloride 1, amino acid 2 and a variety of aldehydes 3. The cyclization followed by condensation of benzoyl chloride, amino acid, and a variety of aldehydes catalyzed by ILs [Et₃NH][HSO₄] and catalytic amount of acetic anhydride and sodium acetate. The final products were confirmed by their characterization data such as FTIR, ¹H-NMR, ¹³C-NMR, Mass, high-resolution mass spectra and were compared with its reported method.     

Silica-supported antimony(III) chloride as an efficient heterogeneous catalyst for the synthesis of aminopropenones and 3-aminopropenoates under solvent-free conditions

A convenient and efficient procedure has been developed for the synthesis of 3-aminoprop-2-en-1-ones and 3-aminoprop-2-enoates catalyzed by silica-supported antimony(III) chloride at room temperature under solvent-free conditions. The reaction takes a short time and ensures good to excellent yields of the products. Both aromatic and aliphatic amines and various 1,3-dicarbonyl compounds, including β-ketoesters and β-diketones, can be involved. Published in Russian in Zhurnal Organicheskoi Khimii, 2009, Vol. 45, No. 1, pp. 25–28. The text was submitted by the authors in English.     

3-Amino-5-mercapto-1,2,4-triazole-functionalized Fe3O4 magnetic nanocomposite as a green and efficient catalyst for synthesis of bis(indolyl)methane derivatives

A core–shell Fe₃O₄@silica magnetic nanocomposite functionalized with 3-amino-5-mercapto-1,2,4-triazole (Fe₃O₄/SiO₂/PTS/AMTA) was prepared using Fe₃O₄ with silica layer, and its surface was modified with 3-amino-5-mercapto-1,2,4-triazole. The novel synthesized magnetite nanocomposite was characterized using various techniques. The catalytic activity of Fe₃O₄/SiO₂/PTS/AMTA was demonstrated in the synthesis of bis(indolyl)methane derivatives under solvent-free conditions. Some of the bis(indolyl)methane derivatives were synthesized through one-pot, three-component reaction of 1 mol of various benzaldehydes or ketones with 2 mol of indole in the presence of Fe₃O₄/SiO₂/PTS/AMTA in good to excellent isolated yields. In addition, the catalyst could be recovered and used for several reaction runs without loss of catalytic activity. The stability of recycled catalyst was investigated. This method has some advantages including experimental simplicity, good to excellent yields, solvent-free conditions and stability and reusability of the catalyst.     

Al(HSO4)3: an efficient and heterogeneous reusable catalyst for the synthesis of 1-amidoalkyl-2-naphthols under thermal solvent-free conditions

An efficient green protocol for the synthesis of 1-amidoalkyl-2-naphthols using a three-component, one-pot condensation reaction of 2-naphthol, aromatic aldehyde and amides in the presence of Al(HSO₄)₃ as heterogeneous catalyst under thermal solvent-free conditions has been described. The present procedure offers advantages such as shorter reaction times, simple work-up procedure, excellent yields, recovery and reusability of catalyst.     

Novel task-specific ionic liquid [Et2NH(CH2)2CO2H][AcO] as a robust catalyst for the efficient synthesis of some pyran-annulated scaffolds under solvent-free conditions

Research on Chemical Intermediates - A novel task-specific ionic liquid, 2-carboxy-N,N-diethylethanaminium acetate denoted as [Et2NH(CH2)2CO2H][AcO], is prepared in an easy process and fully...