Synthesis of a novel poly (ethylene glycol) grafted N,N-dimethylaminopyridine functionalized dicationic ionic liquid and its application in one-pot synthesis of 3,4-dihydropyrano[3,2-c]chromene derivatives in water

A novel magnetic FSM-16 supported ionic liquid/Pd complex as a high performance and recyclable catalyst for the synthesis of pyrano[3,2-c]chromenes

In this work, Fe3O4@FSM-16/IL-Pd was successfully designed and synthesized via a new procedure of palladium(ii) complex immobilization onto magnetic FSM-16 using an ionic liquid, as a novel heterogeneous nanocatalyst. Multiple techniques were employed to characterize this magnetic nanocatalyst such as Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Field Emission Scanning Electron Microscopy (FE-SEM), thermogravimetric analysis (TGA), Transmission electron microscopy (TEM), and Vibrating Sample Magnetometry (VSM). After complete characterization of the catalyst, its catalytic activity was used for the synthesis of pyrano[3,2-c]chromene-3-carbonitriles via the reaction of 4-hydroxycoumarin, aldehyde, and malononitrile under solvent-free conditions. Also, it can be recovered and reused several times without a significant decrease in its catalytic activity or palladium leaching.

Greener synthesis of dimethyl carbonate from carbon dioxide and methanol using a tunable ionic liquid catalyst

Several types of ionic liquids (ILs) performance towards dimethyl carbonate (DMC) synthesis using cheap reactant (methanol) and waste CO2 which is abundantly available in the environment are discussed. We synthesized ILs with cheap raw materials such as ethylene glycol. The main aim of this study is to synthesize efficient catalysts for the production of profitable fuel additives. ILs show high thermal stability, less viscosity, and low vapor pressure. In addition, some ILs have high CO2 absorption capacity due to moderate acid-base properties. These ILs reversibly capture more CO2 which is more efficient towards mass transport of methanol at optimum reaction conditions which enhance the DMC yield. This catalytic system is easily reusable for several reactions without decreased performance under the same reaction conditions. These reaction conditions had an effect on the synthesis of DMC. Temperature, pressure, IL loading, and IL/DMAP ratio were fine tuned. We propose a mechanism which the reaction may follow. The synthesized ILs required moderate reaction conditions and reduce waste gases (CO2) from the environments as they have high CO2 absorption capacity compared to the metal oxide catalyst. Therefore, this catalytic system helps and gives new direction to synthesize new catalyst for other application.

ZIF@ZnTiO3 Nanocomposite as a Reusable Organocatalyst for the Synthesis of 3, 4-dihydropyrano[c]chromene Derivatives

Background:

Dihydropyrano [3, 2-c]chromenes and their derivatives have great attention for scientists. They have different activities such as biological properties, spasmolytic, diuretic, anticoagulant, anti-cancer, and anti-anaphylactic activity. For these vary biological activities, chromene derivatives have made significant for further progress in medicinal and organic synthesis studies. So, in view of the importance of chromenes, we aimed to synthesis of 3, 4-dihydropyrano [3, 2-c] chromene derivatives. ZIF@ZnTiO3nanocomposite as organocatalyst was used.

Method:

An effective and applicable technique was used for preparation of 3, 4-dihydropyrano [3, 2- c] chromene derivatives. Dihydropyrano [c] chromenederivatives were prepared by using ZIF@ZnTiO3compositeas a recyclable catalyst. One-pot three-component reaction of aromatic aldehydes, malononitrile, and 4-hydroxycoumarin was done for synthesis of dihydropyrano [c] chromenederivatives over composite catalyst with excellent yields. The as prepared dihydropyrano [c] chromenederivatives were measured by melting point, FTIR, 1H NMR, and 13C NMR. The nano catalyst could be recycled several times.

Result:

A novel nano catalyst of MOF containing Mn2+ ions and 2- methyl imidazole (ZIF) and zinctitanate (ZIF@ZnTiO3) composite was prepared. The synthesized organocatalyst was studied for preparation of 3, 4-dihydropyrano [3, 2-c] chromene derivatives. One-pot three-component reaction of aromatic aldehydes, malononitrile, and 4-hydroxycoumarin was done for synthesis of dihydropyrano [c] chromene derivatives over composite catalyst with excellent yields. The reaction was optimized.

Conclusion:

The organocatalyst composite of consist of ZIF and zinctitanate was prepared. The ZIF@ZnTiO3 was used as catalyst for synthesis of 3, 4-dihydropyrano [3, 2-c] chromene derivatives via one-pot three-component condensations of aromatic aldehydes,malononitrile, and 4 hydroxycoumarin. The results of melting point, FTIR, 1H NMR, 13C NMR also confirmed the formation of high yield of 3, 4-dihydropyrano [3, 2-c] chromene derivatives at short time. The appealing properties of this method are environmentally friendly, mild reaction conditions (low reaction time and high yields of pure products), easy work up and recyclability of reaction catalyst.

The molecular diversity scope of 4-hydroxycoumarin in the synthesis of heterocyclic compounds via multicomponent reactions

4-Hydroxycoumarins are some of the most versatile heterocyclic scaffolds and are frequently applied in the synthesis of various organic compounds. 4-Hydroxycoumarin-based compounds are important among heterocyclic structures due to their biological and pharmaceutical activities. In this study, we provide an overview on the recent applications of 4-hydroxycoumarin in multicomponent reactions for the synthesis of various heterocyclic compounds during the time period of 2015-2018.

Nanofibre Sepiolite Catalyzed Green and Rapid Synthesis of 2-Amino-4H-chromene Derivatives

Nanofibre sepiolite catalyzed the rapid, clean, and highly efficient synthesis of 2-amino-4H-chromene derivatives by a one-pot, three-component condensation of a series of aldehydes, various enolizable C–H bonds (such as dimedone, α-naphthol, resorcinol, and 4-hydroxy-2H-chromen-2-one), and malononitrile in a mixture of water/ethanol. The present method offers several advantages such as high to excellent yields, short reaction times, mild reaction conditions, simple procedure, use of inexpensive, non-toxic, and naturally available catalyst, easy isolation of the products, and no need for column chromatography. The catalyst could be easily separated from the reaction mixture and can be reused for many consecutive trials without a significant decline in its reactivity.