Ionic liquid supported on magnetic nanoparticles as a novel reusable nanocatalyst for the efficient synthesis of tetracyclic quinazoline compounds

A magnetic ionic liquid supported on γ-Fe₂O₃ nanocatalyst was synthesized successfully and characterized by Fourier transform infrared spectroscopy, vibrating sample magnetometry, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction and scanning electron microscopy. The resulting nano-Fe₃O₄-supported, ionic liquid was an efficient catalyst for preparation of a series of tetracyclic quinazoline compounds by three components reaction of a mixture of isatoic anhydride and amine with ninhydrin in PEG and the desired products were obtained in good to excellent yields. High efficiency, waste-free, mild reaction conditions, effortless magnetic recovery and reusability up to four continuous cycles are the noteworthy features of the currently employed heterogeneous catalytic system.     

TEDETA@BNPs as a basic and metal free nanocatalyst for Knoevenagel condensation and Hantzsch reaction

In this work, Boehmite nanoparticles (BNPs) were synthesized in water using commercially available materials and further N,N,N′,N′-tetraethyldiethylentriamin (TEDETA) was supported on the surface of BNPs, and used as organo-basic catalyst in four-component Hantzsch reaction that provides access to pharmaceutically polyhydroquinoline derivatives and Knoevenagel reaction to afford α,β-unsaturated compounds. All products were obtained in excellent yields (89–98%) and good reaction times under green condition such as water and ethanol solvents. This catalyst was characterized using FT-IR, SEM, EDS, and TGA techniques. This catalyst was reused for several times without the significant loss of their catalytic efficiency. In addition, stability of catalyst after recycling was confirmed by TGA, SEM, EDS and FT-IR techniques.     

Synthesis,crystal structural study and catalyst active of benzyloxycarbonylmethyl triphenylphosphonium hexabromopalladate (II) in amination of aryl halides and Suzuki cross-coupling reaction

In this study, palladium (II) chloride reacted with the phosphonium salt [PhCH₂COOCH₂P(Ph)₃]Br to give [PhCH₂COOCH₂P(Ph)₃]₂[Pd₂Br₆] (1). The characterization of synthesized compound was performed by elemental analysis, FT-IR, ¹H, ³¹P, ¹³C NMR and also X-ray crystallography. It was found that this compound works as an efficient catalyst for the amination of aryl halides to afford primary amines, the results of which were satisfactory. Furthermore, it was found that the catalyst showed a high activity for Suzuki carbon–carbon cross-coupling of aryl halides and phenylboronic acid. Interestingly, the catalyst can be recovered from the reaction mixture and recycled four consecutive runs without any significant loss in activity.     

Chemoselective N-nitrosation of secondary amines under heterogeneous and mild conditions via in situ generation of HNO_2

A wide variety of secondary amines are chemoselectively subjected to N-nitrosation reaction with treatment of citric acid and NaNO2 in the presence of wet SiO2(50%,w/w)in dichloromethane at room temperatture under heterogeneous conditions.The N-nitrosation method is very simle and products can be easily isolated with good to high yields.     

Synthesis and characterization of MCM-41@XA@Ni(II) as versatile and heterogeneous catalyst for efficient oxidation of sulfides and acetylation of alcohols under solvent-free conditions

Herein, Ni(II) immobilized on modified mesoporous silica MCM-41 was designed and synthesized via a facile sequential strategy. The structure of the catalyst was characterized by X-ray diffraction. The thermal property of the as-synthesized materials was studied using thermogravimetric-differential thermal analysis. The average particles size and morphology of MCM-41@XA@Ni(II) were investigated using scanning electron microscopy and transmission electron microscopy. This nanostructure catalyst was effective for the selective oxidation of sulfides and acetylation of alcohols in solvent-free conditions. The easy recyclability of the catalyst and their complete chemoselectivity toward the sulfur group of substrates in the oxidation of sulfides are important “green” attributes of this catalyst.     

A novel method for the reduction of sulfoxides with the N,N,N’,N’-tetrabromobenzene-1,3-disulfonamide (TBBDA)/PPh3 system

A new method is described for the reduction of sulfoxides to sulfides using N,N,N’,N’-tetrabromobenzene-1,3-disulfonamide [TBBDA] in combination with triphenylphosphine. Good to excellent yields, short reaction times, high efficiency and facile isolation of the desired products are the advantages of this method.     

Preparation of DSA@MNPs and application as heterogeneous and recyclable nanocatalyst for oxidation of sulfides and oxidative coupling of thiols

Research on Chemical Intermediates - Dopamine sulfamic acid-functionalized magnetic Fe3O4 nanoparticles (DSA@MNPs) were prepared by a very simple and inexpensive procedure using commercial...     

Synthesis,characterization, and catalytic application of Cr and Mn Schiff base complexes immobilized on modified nanoporous MCM-41

Research on Chemical Intermediates - Immobilization of chromium and manganese Schiff base complexes by postgrafting of ligand then metal salts on the walls of mesoporous MCM-41 functionalized with...     

Synthesis of 2,3-dihydroquinazolin-4(1<Emphasis Type="Italic">H</Emphasis>)-ones,disulfides and sulfoxides catalyzed by a zinc complex immobilized onto functionalized mesoporous MCM-41 as a mild and efficient catalyst

Zinc complex with 2-amino-3-hydroxy-pyridine ligand was immobilized onto chloropropyl-modified mesoporous silica MCM-41 (CP-MCM-41) via post-grafting method. The prepared catalyst has been characterized by low-angle X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive spectrum, atomic adsorption spectroscopy and thermogravimetric analysis. The immobilized nano-structured material showed very good catalytic activity and excellent recycling efficiencies for the oxidation reaction of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides in the presence of aqueous hydrogen peroxide as oxidant at room temperature and the synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives in water.     

Ni-guanidine@MCM-41 NPs: a new catalyst for the synthesis of 4,4ʹ-(arylmethylene)-bis-(3-methyl-1-phenyl-1H-pyrazol-5-ols) and symmetric di-aryl sulfides

In this work, the surface of mesoporous MCM-41 was modified with guanidine, and then, Nickel particles have become immobilized on its surface (Ni-guanidine@MCM-41NPs). This heterogeneous catalyst has been identified by various techniques including: low-angle X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma, thermal gravimetric analysis and N₂ adsorption–desorption measurement isotherms, and its catalytic application was studied in the synthesis of 4,4ʹ-(arylmethylene)-bis-(3-methyl-1-phenyl-1H-pyrazol-5-ol) derivatives and symmetric di-aryl sulfides. The prepared organometallic complex could be isolated, post-reaction, by simple filtration for several consecutive cycles without a notable change in its catalytic activity.