Fabrication of UiO-66 nanocages confined brønsted ionic liquids as an efficient catalyst for the synthesis of dihydropyrazolo[4′,3’:5,6]pyrano[2,3-d]pyrimidines

Metalated covalent organic frameworks as efficient catalysts for multicomponent tandem reactions

Multicomponent tandem reactions have become indispensable synthetic methods due to their economic advantages and efficient usage in natural products and drug synthesis. The emergence of metalated covalent organic frameworks (MCOFs) has opened up new opportunities for the advancement of multicomponent tandem reactions. In contrast to commonly used homogeneous transition metal catalysts, MCOFs possess regular porosity, high crystallinity, and rich metal chelation sites that facilitate the uniform distribution and anchoring of metals within their cavities. Thus, they show extremely high activity and have recently been widely employed as catalysts for multicomponent tandem reactions. It is timely to conduct a review of MCOFs in multicomponent tandem reactions, in order to offer guidance and assistance for the synthesis of MCOF catalysts and their application in multicomponent tandem reactions. This review provides a comprehensive overview of the design and synthesis of MCOFs, their application and progress in multicomponent tandem reactions, and the primary challenges encountered during their current development with the aim of contributing to the promotion of the field.

Synthesis of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite as a superior and reusable heterogeneous catalyst for the preparation of pyrimidine derivatives and investigation of their antimicrobial activities

In this report, we synthesized some pyrimidine derivatives by multi-component reaction of urea, benzaldehydes, and 1,3-indandione in the presence of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite under reflux conditions. Initially, graphene oxide was prepared from graphite, and then it was sulfonated using ClOSO3H. Next, GO-OSO3H nanosheets were used to support ZIF-8/ZnFe2O4 nanostructure. The construction of the synthesized structure was established using different spectral techniques such as X-ray crystallography (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX/Mapping), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). The present method provides various benefits including the efficiency of outcomes, easy separation of the catalyst, and excellent yield of the products within short reaction times. Moreover, the antibacterial activities of pyrimidine derivatives were investigated via the agar-well diffusion method on gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria and the obtained results illustrated reasonable effects.

Discovery of Pyrano[2,3-c]pyrazole Derivatives as Novel Potential Human Coronavirus Inhibitors: Design, Synthesis, In Silico, In Vitro, and ADME Studies

The SARS-CoV-2 pandemic at the end of 2019 had major worldwide health and economic consequences. Until effective vaccination approaches were created, the healthcare sectors endured a shortage of operative treatments that might prevent the infection's spread. As a result, academia and the pharmaceutical industry prioritized the development of SARS-CoV2 antiviral medication. Pyranopyrazoles have been shown to play a prominent function in pharmaceutical chemistry and drug sighting because of their significant bioactive properties. We provide herein a novel sequence of pyranopyrazoles and their annulated systems whose antiviral efficacy and cytotoxicity were explored versus human coronavirus 229E (HCoV-229E) Vero-E6 cell lines as a model for the Coronaviridae family. Fifteen synthetic congeners pointed out miscellaneous antiviral efficacies against HCoV-229E with variable inhibition degrees. Compound 18 showed a high selectivity index (SI = 12.6) that established spectacular inhibitory capacity against human coronavirus 229E. Compounds 6, 7, and 14 exposed moderate efficacies. Compounds 6, 7, 14, and 18 exhibited substantial antiviral action through the replication phase with reduction percentages extending from 53.6%, 60.7%, and 55% to 82.2%, correspondingly. Likewise, when assessed to the positive control tipranavir (88.6%), the inhibitory efficiency of compounds 6, 7, 14, and 18 versus the SARS-CoV2 Mpro provided high percentages of 80.4%, 73.1%, 81.4% and up to 84.5%, respectively. In silico studies were performed to investigate further the biological activity and the target compounds' physical and chemical features, including molecular dynamic (MD) simulations, protein-ligand docking, ADME studies, and density functional theory (DFT) calculations. These inquiries demonstrated that this series of metabolically stable pyranopyrazoles and their annulated systems are effective human coronavirus inhibitors that inhibit the viral Mpro protein and may have emerged as a novel COVID-19 curative option.

Synthesis and characterization of Co-MOF@Ag2O nanocomposite and its application as a nano-organic catalyst for one-pot synthesis of pyrazolopyranopyrimidines

In this study, a Co-MOF was synthesized via a co-precipitation procedure and then used as support for stabilizing Ag ions and producing Co-MOF@Ag2O nanocomposite by microwave irradiation. The characterization of synthesized Co-MOF@Ag2O nanocomposite was performed by using different techniques such as field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) analyses, X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) and Fourier-transform infrared (FT-IR). The prepared Co-MOF@Ag2O nanocomposite was applied as a heterogeneous nano-catalyst in the synthesis of pyrazolopyranopyrimidines in water at 50 °C via the one-pot multicomponent reaction of ethyl acetoacetate, hydrazine hydrate, aromatic aldehydes and barbituric acid derivatives. Through this straightforward and effective protocol, different tricyclic fused pyrazolopyranopyrimidines were synthesized at high yields, and short reaction times, through an uncomplicated work-up process with no by-product. The Co-MOF@Ag2O nanocomposite has been effectively recycled for four consecutive cycles without appreciable loss in its activity. Cost-effectiveness, no need for column chromatography, mild conditions, catalyst recyclability, and eco-friendly nature make it a promising candidate compared to other methods.

Fe3O4@iron-based metal-organic framework nanocomposite [Fe3O4@MOF (Fe) NC] as a recyclable magnetic nano-organocatalyst for the environment-friendly synthesis of pyrano[2,3-d]pyrimidine derivatives

Various pyrano[2,3-d]pyrimidines were synthesized by the multicomponent reaction of aldehydes, malononitrile, and acidic C-H compounds such as barbituric acid through the tandem Knoevenagel-Michael cyclocondensation pathway in an environmentally friendly reactive medium in the presence of a recoverable nanocomposite. This nanocomposite includes Fe₃O₄ nanoparticles placed on an organometallic framework. The synthesized Fe₃O₄@iron-based metal-organic framework nanocomposite was characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, a vibrating sample magnetometer, and thermogravimetric analysis.

Ionic liquid-loaded triazine-based magnetic nanoparticles for promoting multicomponent reaction

A novel hybrid magnetic ionic-liquid as a heterogeneous catalyst was synthesized by hybridization of imidazolium based-ionic liquid onto the nitrogen rich magnetic nanocomposite. The resulting catalyst (n-Fe₃O₄@SiO₂-TA-SO₃H IL) has two advantages besides recyclability: (i) high capacity of functional-SO₃H group with imidazolium-IL cation for promoting symmetric and asymmetric Hantzsch reaction and (ii) easy recovery. Caused by the polymeric and magnetic nature of the n-Fe₃O₄@SiO₂-TA-SO₃H IL, large quantities of acidic groups were bound to the n-Fe₃O₄@SiO₂-TA surface, which reduced the catalyst mass applied to the catalytic reaction. Moreover, superior catalytic performance and outstanding recyclability of n-Fe₃O₄@SiO₂-TA-SO₃H IL in mild condition make this method a green pathway for manufacture of satisfactory chemicals.

Synthesis, DFT calculation, pharmacological evaluation, and catalytic application in the synthesis of diverse pyrano[2,3-c]pyrazole derivatives

Pyranopyrazole and its derivatives are classified to be a pharmacologically significant active scaffold for almost all modes of biological activities. In this work, An efficient, green, and facile three-component reaction for preparing pyrano[2,3-c]pyrazole derivatives via the condensation reaction of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, ethyl acetoacetate, and malononitrile in the presence of ZnO Nanoparticle. The products are produced with high yields and in shorter reaction times. It also is mild, safe, green, and environmentally friendly. The geometric parameters such as dipole moment, bond length, dihedral angles, total energy, heat of formation, atomic charges and energies at a highly accurate for prepared compounds were computed by Denisty Functional Theory along with the B3LYP functional. The newly synthesized compounds were screened for their anti-inflammatory and antioxidant activity. Some of the tested compounds displayed promising activities. The newly prepared compounds were found to be potent towards the antioxidant activity. Results indicated that compounds 11 and 12 exhibited significant (p ≥ 0.05) in vitro total antioxidant activity as 44.93 ± 0.15 and 39.60 ± 0.10 U/ML, respectively higher than standard ascorbic acid (29.40 ± 0.62).

An overview on trace CO2 removal by advanced physisorbent materials

This review paper focuses on various gas processing technologies and materials that efficiently capture trace levels of carbon dioxide (CO₂). Fundamental separation mechanisms such as absorption, adsorption, and distillation technology are presented. Liquid amine-based carbon capture (C-capture) technologies have been in existence for over half a century, however, liquid amine capture relies upon chemical reactions and is energy-intensive. Liquid amines are thus not economically viable for broad deployment and offer little room for innovation. Innovative C-capture technologies must improve both the environmental footprint and cost-effectiveness. As a promising alternative, physisorbents have many advantages including considerably lower regeneration energy. Generally, existing classes of physisorbent materials, such as metal-organic frameworks (MOFs) and zeolites are selective toward C-capture. However, their selectivity is currently not high enough to remove trace levels (e.g., ~1%) of CO₂ from various natural gas process streams. This review summarizes the current advancements in physisorbent materials for CO₂ capture. Here, key performance parameters needed to select the most suitable candidate are highlighted. Furthermore, this review discusses the scope for the development of better performing CO₂ selective physisorbents from both environmental and economic perspectives. In addition, hybrid ultra microporous materials (HUMs), characterized mainly by ultra-micro pores (<0.7 nm), are discussed in reference to C-capture. Various characteristics of HUMs result in high selectivity and applicability in difficult separations such as the gas sweetening and C-capture from complex humid mixed gas streams.