ZrOCl2·8H2O: a highly efficient catalyst for the synthesis of 1,8-dioxo-octahydroxanthene derivatives under solvent-free conditions

Green and efficient one-pot three-component synthesis of novel drug-like furo[2,3–d]pyrimidines as potential active site inhibitors and putative allosteric hotspots modulators of both SARS-CoV-2 MPro and PLPro

In this paper, an environmentally benign, convenient, and efficient one-pot three-component reaction has been developed for the regioselective synthesis of novel 5-aroyl(or heteroaroyl)-6-(alkylamino)-1,3-dimethylfuro[2,3-d]pyrimidine-2,4(1H,3H)-diones (4a‒n) through the sequential condensation of aryl(or heteroaryl)glyoxal monohydrates (1a‒g), 1,3-dimethylbarbituric acid (2), and alkyl(viz. cyclohexyl or tert-butyl)isocyanides (3a or 3b) catalyzed by ultra-low loading ZrOCl₂•8H₂O (just 2 mol%) in water at 50 ˚C. After synthesis and characterization of the mentioned furo[2,3-d]pyrimidines (4a‒n), their multi-targeting inhibitory properties were investigated against the active site and putative allosteric hotspots of both SARS-CoV-2 main protease (M^Pro) and papain-like protease (PL^Pro) based on molecular docking studies and compare the attained results with various medicinal compounds which approximately in three past years were used, introduced, and or repurposed to fight against COVID-19. Furthermore, drug-likeness properties of the mentioned small heterocyclic frameworks (4a‒n) have been explored using in silico ADMET analyses. Interestingly, the molecular docking studies and ADMET-related data revealed that the novel series of furo[2,3-d]pyrimidines (4a‒n), especially 5-(3,4-methylendioxybenzoyl)-6-(cyclohexylamino)-1,3-dimethylfuro[2,3-d]pyrimidine-2,4(1H,3H)-dione (4g) as hit one is potential COVID-19 drug candidate, can subject to further in vitro and in vivo studies. It is worthwhile to note that the protein-ligand-type molecular docking studies on the human body temperature-dependent M^Pro protein that surprisingly contains zinc^II (Zn^II) ion between His41/Cys145 catalytic dyad in the active site, which undoubtedly can make new plans for designing novel SARS-CoV-2 M^Pro inhibitors, is performed for the first time in this paper, to the best of our knowledge.

Facile and efficient synthesis of xanthenedione derivatives promoted by niobium pentachloride

Xanthenedione derivatives were synthesised in one-pot reactions between arylaldehyde derivatives and 1, 3-cyclohexanedione promoted by niobium pentachloride. This new method is simple, cost-effective, high-yielding with a good variety of substrates generality, and can be conducted within reasonable reaction times.

A unique opportunity for the utilization of glass wastes as a resource for catalytic applications: toward a cleaner environment

n-glass-waste-SO₃H at the service of catalytic application.

Water mediated reactions: TiO2and ZnO nanoparticle catalyzed multi component domino reaction in the synthesis of tetrahydroacridinediones, acridindiones, xanthenones and xanthenes

Tetrahydroacridine-1,8-(2H,5H,9H,10H)-diones4from 1,3-cyclohexanedione and/or dimedone 1,2-chloro-3-formylquinoline2and anilines3in water at 90 °C were obtained by domino reaction approach.

Secondary amine based ionic liquid: an efficient catalyst for solvent free one pot synthesis of xanthenes and benzoxanthenes

Amine based ionic liquid was reported as an efficient and easily recyclable catalyst for the solvent free environmental benign synthesis of xanthene and benzoxanthene derivatives within 10–30 minutes.

Recent advances in the application of deep eutectic solvents as sustainable media as well as catalysts in organic reactions

This review highlights the recent advances using deep eutectic solvents (DESs), deep eutectic ionic liquids (DEILs), low-melting mixtures (LMMs) or low transition temperature mixtures (LTTMs) as green media as well as catalysts in organic reactions.

Fe3O4@SiO2–imid–PMAnmagnetic porous nanospheres as recyclable catalysts for the one-pot synthesis of 14-aryl- or alkyl-14H-dibenzo[a,j]xanthenes and 1,8-dioxooctahydroxanthene derivatives under various conditions

Synthesis of 14-aryl- or alkyl-14H-dibenzo[a,j]xanthenes and 1,8-dioxooctahydroxanthene derivatives by Fe₃O₄@SiO₂–imid–PMA nanocatalysts.

A highly efficient green synthesis of 1, 8-dioxo-octahydroxanthenes

SmCl₃ (20 mol%) has been used as an efficient catalyst for reaction between aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione at 120°C to give 1,8-dioxo-octahydroxanthene derivatives in high yield. The same reaction in water, at room temperature gave only the open chain analogue of 1,8-dioxo-octahydroxanthene. Use of eco-friendly green Lewis acid, readily available catalyst and easy isolation of the product makes this a convenient method for the synthesis of either of the products.