Ce(IV) immobilized on halloysite nanotube–functionalized dendrimer (Ce(IV)–G2): A novel and efficient dendritic catalyst for the synthesis of pyrido[3,2‐c]coumarin derivatives

Abstract

In this study, a new and stable Ce(IV) immobilized on halloysite nanotubefunctionalized dendrimer was designed, synthesized, and characterized using Fourier-transform infrared, elemental analysis, thermogravimetric analysis, field emission scanning electron microscopy, scanning electron microscopyenergy dispersive X-ray spectroscopy, transmission electron microscopy, dynamic light scattering, Brunauer-Emmett-Teller, and inductively coupled plasma optical emission spectroscopy techniques. This catalyst was efficiently used for the one-pot, single-step multicomponent synthesis of pyrido[3,2-c] coumarins from 4-aminocoumarin, aldehydes, and aryl ketones. The efficiency and selectivity of this catalytic system were also evaluated for the synthesis of pyrido[3,2-c]coumarins from terminal/internal alkynes instead of aryl ketones. In this respect, the regioselectivity of the products was successfully assigned by X-ray crystallographic analysis. All these reactions were best performed under solvent-free conditions in the presence of only 0.28 mol% of the catalyst, and such a one-pot multicomponent synthesis of pyrido[3,2-c]coumarins is reported for the first time. It is also worth noting that single-step and short reaction path for the synthesis of a variety of pyrido[3,2-c]coumarins along with excellent reusability of this dendritic catalyst makes this method economically and environmentally attractive.

Triazine bis(pyridinium) hydrogen sulfate ionic liquid immobillized on functionalized halloysite nanotubes as an efficient catalyst for one-pot synthesis of naphthopyranopyrimidines

“…Consequently, the growth of new sustainable catalytic system for the synthesis of fine chemicals is still of great significance. In this sense and also, in continuation of our previous works, 14 we herein report the synthesis and application of 1,1′-(6-(propyl amino)-1,3,5-triazine-2,4-diyl)bis(pyridinium) hydrogen sulfate immobillized on functionalized halloysite nanotubes [(PATDBP)(HSO 4 ) 2 @HNT] as a recoverable and reusable catalyst for the synthesis of naphthopyranopyrimidine derivatives via a three-component reaction under solvent-free conditions ( Scheme 1 ).…”

Effect of support hydrophobicity of halloysite‐based catalysts on the polyalphaolefin hydrofinishing performance

“…In the standard sample, Hal/Pd, Pd nanoparticles were immobilized on unmodified Hal. [ 70 ] In the second sample, Hal/CTAB/Pd, Hal outer surface was first modified with CTAB, and then the resultant hydrophobic Hal was used as a support for the stabilization of Pd nanoparticles. Finally, to elucidate whether the order of introduction of CTAB can affect the activity of the resultant catalyst, a third sample, Hal/Pd/CTAB, was also prepared, in which Hal was first palladated and then treated with CTAB.…”

Halloysite Nanotubes: Smart Nanomaterials in Catalysis

“…Covalent modified HNTs with chlorine atoms (HNTs-Cl) were used as scaffolds for the dendrimers synthesis, which can efficiently immobilized Ce(IV) ions for catalytic purposes (Figure 8) [95]. The obtained nanomaterial was employed as a catalyst in the synthesis of a series of pyrido[3,2-c]coumarins via a one-pot, single step, three-component reaction of 4-aminocoumarin, aldehydes and aryl ketones.…”