Fabricated Fe3O4 as an efficient catalyst for the synthesis of naphthapyranopyrimidines and 5-aryl-1, 2, 4-triazolidine-3-thione under microwave irradiation

The work described herein employs potassium hydroxide impregnated alumina (KOH-alumina) as a mild, efficient, and recyclable catalyst for a one-pot solvent-free and environmentally safer synthesis of 3,4,6-triarylpyridazines and some substituted pyridazines from active methylene carbonyl species, 1,2-dicarbonyls, and hydrazine hydrate by microwave (MW) irradiation. The method offers highly convergent, inexpensive, and functionality-tolerable procedure for rapid access to important pyridazine compounds in good yields.

Exploration of copper-cysteamine nanoparticles as an efficient heterogeneous Fenton-like catalyst for wastewater treatment

Background: Choline chloride-thiourea/sulfuric acid is a powerful and efficient green catalyst used for one-pot synthesis of quinazoline-4 (3H)-one derivatives via a reaction between various amines, acetic anhydride, and anthranilic acid under microwave irradiation and solventfree conditions (4a-q). Microwave irradiation, which is a faster, more cost-effective, less energyintensive, and more efficient method than conventional heating, has been used to synthesize some quinazolinone derivatives. Introduction: For the past ten years, one of the major subjects in synthetic organic chemistry has been green synthesis, which has used efficient and environmentally friendly methods to synthesize biological compounds. The use of catalysts has significant advantages, including ease of preparation and separation, chemical and thermal stability, and environmental friendliness due to features such as reusability, low cost, and efficient and easy workup techniques. Therefore, the mechanism is performed by a non-toxic organic catalyst that uses the least amount of energy and chemical reactants in accordance with the principles of green chemistry and the least waste. Methods: One-pot and sequential addition methods have been used to synthesize quinazolinone derivatives. In the sequential addition method, the reaction was started by adding acetic anhydride and anthranilic acid to the reaction vessel under microwave irradiation and continued by adding choline chloride thiourea/sulfuric acid as efficient, recyclable green catalysts and the desired amine. In vitro, the well diffusion method against different pathogenic strains was used to evaluate the antimicrobial activity of quinazoline-4 (3H)-one derivatives. Pathogenic strains used were Candida albicans ATCC 10231 (yeast), Aspergillus niger ATCC 16404 (fungus), Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 (bacteria) and ATCC 6538, and Staphylococcus aureus S. epidermidis ATCC 12228. Pyrimidine-containing compounds, in which the 3- hydroxyl, 2,5-dimethoxy, 4-bromo, 4‐methoxy, and 4‐chloro groups are attached to the phenyl ring of pyrimidine, exhibit antimicrobial properties. Results: In a short reaction time, a variety of biologically active quinazolinone derivatives were synthesized with high efficiency. According to the results, it was found that with aliphatic amines, the reaction time was shorter, and the reaction efficiency was higher. Products synthesized from aromatic amines had more antibacterial properties. Conclusion: In this work, a variety of 2-methyl-quinazoline-4 (3H)-one derivatives (4a–q) were synthesized as potent antibacterial agents under microwave irradiation and solvent-free conditions in the presence of ChCl-thiourea/H2SO4 as an efficient, eco-friendly, and recyclable catalyst.

An efficient and rapid method for the synthesis of 3,4,5-substituted furan-2 (5H)-ones has been achieved through a three-component reaction of aniline, dialkyl acetylenedicarboxylate, and aromatic aldehydes using nano-colloidal silica-tethered polyhedral oligomeric silsesquioxanes with eight branches of 3-aminopropyltriethoxysilane (nano-colloidal silica @APTPOSS) as a superior catalyst under microwave irradiations. Microwave irradiation (MWI) is utilized for a diversity of organic syntheses due to short reaction times, easy workup and good yields. The use of highly efficient, economic and retrievable catalysts, with low or nil toxicity is required from the green chemistry viewpoint. Nano-colloidal silica@APTPOSS has been characterized by 1H NMR spectroscopy, dynamic light scattering (DLS), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA). In this research, microwave irradiation is used as a green and complementary technique for preparation of furan-2 (5H)-ones. The reusability of the catalyst and little catalyst loading, excellent yields, short reaction times, using the microwave as green process and an alternative energy source are some benefits of this method.

3D printing of a palladium-alumina cermet monolithic catalyst: catalytic evaluation in microwave-assisted cross-coupling reactions

In the present paper, we report the success- ful synthesis of nanocrystalline M II Zr4(PO4)6 ceramics (M: Mn, Ni, Fe, Co). These nano-structures were characterized by X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometer (VSM). Size of nano-structures was in the range of 20-150 nm. Nano-M II Zr4(PO4)6 as an efficient and green catalyst has been used for the preparation of 2-amino-4H-pyran-3,5-dicarboxylate derivatives by the three-component condensation reaction of ethyl cyanoacetate, ethyl acetoacetate, and various aromatic aldehydes under microwave irradiation. Extraordinar- ily, the best results were obtained using MnZr4(PO4)6 nanocrystallines as an efficient catalyst. This method provides several advantages including easy work-up, excellent yields, short reaction times, using of micro- wave as green method, recoverability of the catalyst, and little catalyst loading.

The activity of [Pd{C6H4(CH2N(CH2Ph)2)}(μ‐Br)]2 complex was investigated in cross‐coupling reactions of triethoxy(phenyl)silane with various aryl halides under microwave irradiation. This complex is an efficient and stable catalyst for the synthesis of substituted biphenyls that is non‐sensitive to air and moisture. The combination of dimeric complex as homogenous catalyst, microwave irradiation, DMF as microwave‐active polar solvent and TBAF as microwave‐active additive led to excellent yields in short reaction times. Copyright © 2012 John Wiley & Sons, Ltd.

A solvent-free protocol for the synthesis of β-amino alcohols (Yield, up to 94%) is demonstrated by the ring-opening reactions of meso and terminal epoxides with aromatic amines using Hβ zeolite as catalyst under microwave irradiation. The catalytic system is 80 times faster than the reaction conducted at RT with six times catalyst recyclability. The ring-opening reactions of meso and terminal epoxides with aromatic amines proceeds smoothly using Hβ zeolite as catalyst under microwave irradiation.

Solid-supported ruthenium(0) was synthesized by the reduction deposition method and used as a heterogeneous catalyst for the hydration of nitriles to amides under microwave irradiation. A wide range of aromatic, α,β-unsaturated and aliphatic nitriles were efficiently converted to their corresponding primary amides under milder conditions. The catalyst was found to be very stable under moisture and microwave irradiation, easily separable from the reaction mixture, to cause negligible metal contamination of the product and was recyclable up to ten times without significant loss of catalytic activity.

Solid-supported ruthenium(0) was synthesized by the reduction deposition method and used as a heterogeneous catalyst for the hydration of nitriles to amides under microwave irradiation. A wide range of aromatic, α,β-unsaturated and aliphatic nitriles were efficiently converted to their corresponding primary amides under milder conditions. The catalyst was found to be very stable under moisture and microwave irradiation, easily separable from the reaction mixture, to cause negligible metal contamination of the product and was recyclable up to ten times without significant loss of catalytic activity.

Microwave-assisted organic transformation is currently gaining prominence in the field of benign organic synthesis. In this work, we reported Ru nanoparticles (NPs) (<5 nm) supported on titanium dioxide (TiO2) using the facile and fast molten-salt method and employed for reductive N-alkylation reactions, nitroarenes to amines and levulinic acid (LA) to levulinate ester under microwave irradiation (MWI). Reductive N-alkylation of nitrobenzene and furfural to the respective secondary amines via catalytic transfer hydrogenation with conventional heating (CH) involves longer reaction times, lower selectivity, and low yields. Moreover, the catalytic applications of Ru/TiO2 were explored for the reductive amination of nitrobenzene and furfural with excellent conversion (>99%) and selectivity (85%) toward N-(furan-2-ylmethyl) aniline. The Ru/TiO2 is used as a model to catalyze the conversion (>99%) of nitrobenzene in both the reaction, i.e., nitrobenzene reduction and one-pot reductive amination, along with LA esterification reaction via MWI. To study the efficacy of MWI for nitrobenzene conversion, MWI and CH were compared. MWI is proven to accelerate reaction times and improve nitrobenzene conversion efficiencies when compared to CH by examining the effects of conversion and reaction duration. A remarkable synergistic effect has been revealed between small Ru NPs and TiO2 NPs that leads to selective catalytic transformation of organic compounds to value-added products. As per the study’s findings, MW is a potentially effective method for improving the conversion of nitrobenzene, with Ru/TiO2 emerging as the most active catalyst compared to as-synthesized Cu/TiO2, and Ni/TiO2.

Réactions d'acylation sous irradiation micro-onde. II. Acylation d'éthers aromatiques

The conversion of vanillin from biomass is an important sustainable practice, enabling the generation of valuable products from renewable resources. This study considered the aldol condensation of vanillin with acetone using conventional heating and microwave irradiation, catalyzed by hydrotalcite‐type materials. These catalysts were synthesized via a combined mechanochemical coprecipitation method to reduce synthesis time and waste. Variables such as molar metal ratio and isomorphic substitution in hydrotalcite with nickel species were explored. The results show that hydrotalcites are efficient catalysts for the aldol condensation of vanillin, achieving conversion rates of 60% to 90% within 120 min under microwave irradiation. This approach aligns with green chemistry principles, offering high selectivity and rapid reaction times, and highlighting the efficiency of hydrotalcites in catalytic applications.

Ag nanoparticles in A4 zeolite as efficient catalysts for the 4-nitrophenol reduction

Catalytic degradation of orange G under microwave irradiation with a novel nanohybrid catalyst