Recyclable Base Catalyst Research Articles

Choline hydroxide, an efficient, green, and recyclable base catalyst, promoted the synthesis of 3-aroylflavones via Baker–Venkataraman rearrangement

ABSTRACT 3-Aroylflavones, a new synthesized group of flavones, have been recently studied via Baker–Venkataraman rearrangement under ‘one-pot’ or sequential ‘one-pot’ reaction conditions. Choline hydroxide, an inexpensive, easily prepared, and green homogeneous catalyst has been found to be the most efficient catalyst among several base catalysts such as KOH/pyridine, KOH/triethylamine, and CaO-ES/triethylamine in the sequential ‘one-pot’ synthesis of 3-aroylflavones. Moreover, the catalyst’s efficiency, and high recyclability to six times without considerable loss of 3-aroylflavones have enhanced the importance of the procedure. Furthermore, 1D-NMR, 2D-NMR, and HRMS have also been used to elucidate the structures of synthesized compounds.

Imidazolium based Ionic liquid Anchored over Dendritic Mesoporous Silica Nanospheres possessing a Magnetic Core as an Efficient and Recyclable Base Catalyst

AbstractIn this study, Magnetic core‐shell dendritic mesoporous silica nanospheres immobilized with imidazolium‐based di‐cationic ionic liquid (Fe3O4@SiO2@DSiO2‐Im‐IL) possessing a large surface area and numerous active site for adsorption of various molecules to carry out organic transformations have been successfully developed. The synthesized nanocatalyst was found to be easily recyclable by applying external magnetic force. The structure, morphology, thermal stability, and magnetic behavior of the synthesized magnetic nanocatalyst were confirmed by different physiochemical techniques like FT‐IR, P‐XRD, FE‐SEM, TGA, VSM, BET, and TEM analysis. The efficiency of the developed heterogeneous nanocatalyst has been investigated for the green synthesis of numerous benzopyran derivatives by employing different aldehydes and active methylene compounds. The catalyst exhibits marvellous activity and efficiency in terms of high product yield, less catalyst use, and wide substrate scope even at room temperature. Finally, after the successful formation of the product, the catalyst was regenerated by utilizing an external magnetic field. The catalyst has been reused multiple times without any noteworthy loss in its activity which confirms the stability of the developed catalyst. The preparation of the catalyst is cost‐effective, and shows atom economy with the utilization of green solvent and without any waste production, which authenticates that it could be a greener pathway for the synthesis of the benzopyran derivatives.

Magnetic core–shell dendritic mesoporous silica nanospheres anchored with diamine as an efficient and recyclable base catalyst

In the present study, diamine-functionalized magnetic core–shell dendritic mesoporous silica nanospheres have been successfully synthesized by an oil–water biphasic stratification-coating strategy.

ChemInform Abstract: Microwave‐Promoted Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐(thio)ones Using IL‐ONO as Recyclable Base Catalyst under Solvent‐Free Conditions.

AbstractThe introduced nitrite ionic liquid can be reused as catalyst for five consecutive cycles of the Biginelli reaction without loss in efficiency.

Microwave-Promoted Synthesis of 3,4-Dihydropyrimidin-2(1H)-(thio)ones Using IL-ONO as Recyclable Base Catalyst Under Solvent-Free Conditions

A mild, efficient, and solvent-free microwave (MW)–promoted Biginelli reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)-(thio)ones in nitrite ionic liquid (IL-ONO) is described. This ionic liquid is a weak Lewis base catalyst, which can be easily recovered and reused in several runs. The satisfactory results were obtained with good yields and short reaction time, using a simple experimental procedure.

Synthesis of dimethyl carbonate via transesterification of ethylene carbonate with methanol using poly-4-vinyl pyridine as a novel base catalyst

Abstract The synthesis of dimethyl carbonate (DMC) via transesterification of ethylene carbonate with methanol using poly-4-vinyl pyridine (PVP) as a novel, homogeneous, recyclable base catalyst with high yield has been reported. The comparative study for the basicity of PVP was also carried out with other basic polymer such as polyvinylpyrrolidone for DMC synthesis. The catalyst was reused for three consecutive recycles without significant loss of activity/selectivity performance. The effect of different reaction parameters like catalyst loading, reaction time, temperature, CO 2 pressure etc. were investigated in detail for the title reaction.