Synthesis of amidoalkyl naphthols by nano-Fe3O4 modified carbon nanotubes via a multicomponent strategy in the presence of microwaves

Sulfonated β-cyclodextrins: efficient supramolecular organocatalysts for diverse organic transformations

The present review summarizes various organic transformations carried out by using sulfonated β-cyclodextrins such as β-cyclodextrin sulfonic acid, β-cyclodextrin propyl sulfonic acid, and β-cyclodextrin butyl sulfonic acid as an efficient, supramolecular reusable catalyst under diverse reaction conditions.

Copper(II) Anchored on Amine-Functionalized MMT: A Highly Efficient Catalytic System for the One-Pot Synthesis of Bispyrano[2,3-c]pyrazole Derivatives

In this study, preparation of pyridine-2-carboimine copper complex immobilized on amine-functionalized nanoclay montmorillonite K10 was reported. The products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and thermogravimetric analysis (TGA). The catalytic activity of this new nanocatalyst, as a natural, renewable, inexpensive, and heterogeneous catalyst, was very effective for the four-component condensation reaction of hydrazine hydrate (or phenyl hydrazine), malononitrile, β-ketoester, and terephthalaldehyde (or isophthalaldehyde) toward the synthesis of multisubstituted bispyrano[2,3-c]pyrazole derivatives. From the viewpoint of green chemistry, the advantages of this approach are accessibility, simplicity, and high yields synthesis. The catalyst was recycled and reused four times without significant loss of activity.

Adipic Acid as a Biodegradable Solid Acid Catalyst for One-Pot, Three Component Synthesis of 1-Amidoalkyl-2-naphthols

Background:

1-Amidoalkyl-2-naphthols are an attractive group of organic compounds that can be converted to oxazine heterocycles and aminoalkyl naphthols. The derivatives of 1- amidoalkyl-2-naphthols have significant biological activities and act as drug candidates.

Methods:

1-Amidoalkyl-2-naphthols were synthesized via the three-component condensation reaction of 2-naphthol, acetamide/benzamide and various aldehydes in the presence of 10 mol% of adipic acid as an organocatalyst under solvent-free conditions at 120°C.

Results:

A simple, efficient, and operative method for the synthesis of 1-amidoalkyl-2-naphtholes in the presence of adipic acid as the biodegradable catalyst is introduced. Easy operation, acceptable reaction times, eco-friendly, availability of starting materials, simple separation of products, and high yields of products are the significant results of this method.

Conclusion:

In this study, 1-amidoalkyl-2-naphthols were synthesized using commercially available reactants in excellent yields and relatively shorter times. In this process, microwave or ultrasonic waves were not used to provide energy for the reaction.

Catalytic degradation of diclofenac from aqueous solutions using peroxymonosulfate activated by magnetic MWCNTs-CoFe3O4 nanoparticles

CoFe₃O₄ nanoparticles supported on multi-walled carbon nanotubes (MWCNTs-CoFe₃O₄) were synthesized by the co-precipitation method as a novel catalyst for degradation of diclofenac (DCF). The comparative experiments indicated that MWCNTs-CoFe₃O₄ has a better catalytic activity in degradation of DCF and activation of peroxymonosulfate (PMS) compared to other catalytic systems. This can be attributed to the interaction of MWCNTs with CoFe₃O₄ in accelerating the absorption process and activating the PMS (E_a = 22.93 kJ mol⁻¹). The removal efficiencies of DCF and total organic carbon (TOC) were 99.04% and 50.11%, under optimum conditions, e.g., pH of 7, PMS dosage of 4 mM, DCF concentration of 30 mg L⁻¹, catalyst dosage of 500 mg L⁻¹, and reaction time of 120 min. The oxidation of DCF was fitted by the pseudo-first-order kinetic model and the constant rate was increased by increasing the pH, temperature, dosage of PMS and catalyst. The production of reactive species was studied using scavengers such as TBA and ethanol and the results showed that sulfate radical is the reactive species responsible for the degradation of DCF. The MWCNTs-CoFe₃O₄ catalyst showed high stability and reusability based on five successful repeated reactions, X-ray diffraction and energy dispersive X-ray spectroscopy analysis. Based on the intermediates detected by gas chromatography-mass spectrometry (GC-MS), the possible pathways for DCF catalytic oxidation were proposed. The results explained that the PMS/MWCNTs-CoFe₃O₄ system is a promising method for treating DCF solution due to high efficiency, good reusability of catalyst and greater PMS activation.

The MWCNTs-CoFe₃O₄ as a novel catalyst showed high catalytic activity in activation of proxymonosulfate for degradation of diclofenac.

Crosslinked chitosan nanoparticle-anchored magnetic multi-wall carbon nanotubes: a bio-nanoreactor with extremely high activity toward click-multi-component reactions

In the present study, we have designed a procedure for the synthesis of a bio-nanoreactor catalyst, crosslinked chitosan nanoparticle-anchored magnetic multi-wall carbon nanotubes (CS NPs/MWCNT@Fe₃O₄), via an in situ ionotropic gelation method.