N,N‐dimethylamino‐functionalized basic ionic liquid catalyzed one‐pot multicomponent reaction for the synthesis of 4H‐benzo[b]pyran derivatives under solvent‐free condition

Chen, Lu; Li, Yiqun; Huang, Xu-Jiang; Zheng, Wenjie

doi:10.1002/hc.20516

Cited by 49 publications

(6 citation statements)

References 17 publications

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“…It seems that the reaction was carried out to proceed through a Knoevenagel–Carba–Michael–Thorpe–Ziegler-type cascade method . Recently, various heterogeneous or homogeneous catalysts such as ionic liquids, diammonium hydrogen phosphate (DAHP), α-Fe 2 O 3 nanoparticles, H 6 P 2 W 18 O 62 ·18H 2 O, cetrimonium bromide, Mg–La mixed metal oxides, silica-grafted ionic liquid, TiCl 4 , InCl 3 , triethylbenzylammonium chloride, Preyssler heteropoly acid, and γ-alumina . However, each of these approaches may have its own merits and some typical shortcomings like high cost, long reaction times, high temperature, usage of toxic solvent, low product yields, and difficulty of removal and recovery.…”

Section: Introductionmentioning

confidence: 99%

Design of a Schiff Base Complex of Copper Coated on Epoxy-Modified Core–Shell MNPs as an Environmentally Friendly and Novel Catalyst for the One-Pot Synthesis of Various Chromene-Annulated Heterocycles

et al. 2021

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An ecofriendly inorganic–organic hybrid and novel Schiff base complex of copper coated on epoxy-modified Fe3O4@SiO2 MNPs was successfully designed and prepared from readily available chemicals. In this method, a Schiff base complex as a linker is utilized to protect copper nanoparticles to the core–shell Fe3O4 exterior without agglomeration. The resulted Schiff base complex of copper coated on epoxy-modified Fe3O4@SiO2 MNPs was characterized and confirmed via different analyses such as FT-IR, TGA, XRD, VSM, FE-SEM, TEM, ICP, EDX, and BET. The novel catalyst was examined for the synthesis of various chromene-annulated heterocycles through the one-pot three component reaction of aromatic aldehydes, various phenols (2-hydroxynaphthalene-1,4-dione/resorcinol/β-naphthol), and malononitrile in ethanol at reflux conditions. This method includes important aspects like no usage of column chromatography, very short reaction times, simplicity of product isolation using ethanol, excellent yields, simple procedures, and magnetic recoverability of the catalyst. All in all, our method makes a novel and significant advancement in the synthesis of various chromene-annulated heterocycles.

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Section: Introductionmentioning

confidence: 99%

Design of a Schiff Base Complex of Copper Coated on Epoxy-Modified Core–Shell MNPs as an Environmentally Friendly and Novel Catalyst for the One-Pot Synthesis of Various Chromene-Annulated Heterocycles

et al. 2021

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“…The reaction mechanism most widely accepted implies an initial Knoevenagel condensation between reagents, and it has been frequently suggested as operative in the synthesis of coumarins, chromenes, , and 2-amino-chromenes ,, by condensation between the acceptor carbonyl and an activated methylenic group. − In this sense, Costa et al proposed the Knoevenagel reaction, followed by a Michael addition and heterocyclization, in the synthesis of 2-amino-4 H -chromenes from salicylaldehyde and malononitrile with a base or an amine . In imidazolium-based ILs, the initial Knoevenagel-then-heterocyclization route has been also proposed in the one-pot synthesis of 2-amino-4 H -chromenes − from salicylaldehyde and malononitrile, and related heterocycles. − In this respect, Wang et al reported a DFT study of the reaction mechanism following the initial Knoevenagel condensation, but no alternative pathways were evaluated …”

Section: Introductionmentioning

confidence: 99%

Imidazolium Sulfonates as Environmental-Friendly Catalytic Systems for the Synthesis of Biologically Active 2-Amino-4H-chromenes: Mechanistic Insights

et al. 2015

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Ionic Liquids (ILs) are valuable reaction media extremely useful in industrial sustainable organic synthesis. We describe here the study on the multicomponent reaction (MCR) between salicylaldehyde (2) and ethyl cyanoacetate (3), catalyzed by imidazolium sulfonates, to form chromenes 1, a class of heterocyclic scaffolds exhibiting relevant biological activity. We have clarified the reaction mechanism by combining the experimental results with computational studies. The results reported herein suggest that both the imidazolium core and the sulfonate anions in the selected ILs are involved in the reaction course acting as hydrogen bond donors and acceptors, respectively. Contrarily to the most widely accepted mechanism through initial Knoevenagel condensation, the most favorable reaction pathway consists of an aldolic reaction between reagents followed by heterocyclization, subsequent dehydration, and, finally, the Michael addition of the second molecule of ethyl cyanoacetate (3) to yield the chromenes 1.

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“…A wide range of aromatic aldehydes easily undergoes condensation with malononitrile and 5,5-dimethylcyclohexane-1,3-dione (dimedone) under solvent-free condition to afford the desired products of good purity in excellent yields. Taking into account environmental and economical considerations, the protocol presented here had the merits of environmentally benign, simple operation, convenient workup, and good yields [135].…”

Section: Synthesis Of 4h-benzo[b]pyranmentioning

confidence: 99%

Basic ionic liquids. A short review

Hajipour

Rafiee

2009

JICS

174

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Basic ionic liquids as environmental-friendly solvents and catalysts with high activity and selectivity and easily recovered materials were used to replace traditional bases such as KOH, NaOH, K 2 CO 3 , NaHCO 3 , NaOAc, triethylamine, or tetrabutylammonium acetate. Using the traditional bases generally suffered from disadvantages such as waste production, corrosion and environmental problems. Basic ionic liquids offering a new possibility for developing environmentally friendly basic catalysts due to the combination of the advantages of inorganic bases and ionic liquids. They are flexible, nonvolatile, noncorrosive, and immiscible with many organic solvents. Basic ionic liquids (BILs) have been used in base-catalyzed processes such as Michael addition, Markovnikov addition, Knoevenagel condensation, Henry reaction, Mannich reaction, oximation, FeistBenary reaction and etc. In this short review, we wish to present an overview of the types, properties, synthesis and applications of basic ionic liquids.

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N,N‐dimethylamino‐functionalized basic ionic liquid catalyzed one‐pot multicomponent reaction for the synthesis of 4H‐benzo[b]pyran derivatives under solvent‐free condition

Cited by 49 publications

References 17 publications

Design of a Schiff Base Complex of Copper Coated on Epoxy-Modified Core–Shell MNPs as an Environmentally Friendly and Novel Catalyst for the One-Pot Synthesis of Various Chromene-Annulated Heterocycles

Design of a Schiff Base Complex of Copper Coated on Epoxy-Modified Core–Shell MNPs as an Environmentally Friendly and Novel Catalyst for the One-Pot Synthesis of Various Chromene-Annulated Heterocycles

Imidazolium Sulfonates as Environmental-Friendly Catalytic Systems for the Synthesis of Biologically Active 2-Amino-4H-chromenes: Mechanistic Insights

Basic ionic liquids. A short review

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