An Eco‐friendly Catalytic System for One‐pot Multicomponent Synthesis of Diverse and Densely Functionalized Pyranopyrazole and Benzochromene Derivatives

An external base‐free, efficient, cost‐effective, and environmentally benign protocol has been developed for the one‐pot multicomponent synthesis of highly functionalized pyranopyrazoles and benzochromenes using water extract of Agave americana (century plant) leaf ash, a waste‐derived catalyst, at room temperature. Mild reaction conditions, high yield, easy isolation of products, eco‐friendly standards, and no chromatographic separation are the salient features of this protocol.     

Deciphering the Potential of Pre and Pro-Vitamin D of Mushrooms against Mpro and PLpro Proteases of COVID-19: An In Silico Approach

Vitamin D’s role in combating the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the virus causing COVID-19, has been established in unveiling viable inhibitors of COVID-19. The current study investigated the role of pre and pro-vitamin D bioactives from edible mushrooms against Mpro and PLpro proteases of SARS-CoV-2 by computational experiments. The bioactives of mushrooms, specifically ergosterol (provitamin D₂), 7-dehydrocholesterol (provitamin-D₃), 22,23-dihydroergocalciferol (provitamin-D₄), cholecalciferol (vitamin-D₃), and ergocalciferol (vitamin D₂) were screened against Mpro and PLpro. Molecular docking analyses of the generated bioactive protease complexes unravelled the differential docking energies, which ranged from −7.5 kcal/mol to −4.5 kcal/mol. Ergosterol exhibited the lowest binding energy (−7.5 kcal/mol) against Mpro and PLpro (−5.9 kcal/mol). The Molecular Mechanics Poisson–Boltzmann Surface Area (MMPBSA) and MD simulation analyses indicated that the generated complexes were stable, thus affirming the putative binding of the bioactives to viral proteases. Considering the pivotal role of vitamin D bioactives, their direct interactions against SARS-CoV-2 proteases highlight the promising role of bioactives present in mushrooms as potent nutraceuticals against COVID-19.     

Nucleophilic Ring-Opening of Benzoxazinones by DBU: Some Observations

This communication demonstrates the formation of an unusual nucleophilic ring opening of benzoxazinones by 1,8-diazabicycloundec-7-ene (DBU). This observation contradicts the intrinsic feature of a hindered nonnucleophilic base like DBU. Confirmation of the product was achieved via single-crystal X-ray diffraction studies.     

Expedient Synthesis of 2‐Carboethoxy‐4‐methylnaphthalenes

A three‐step synthesis of 2‐carboethoxy‐4‐methylnaphthalenes 7a–d from aryl aldehydes is described.     

Catalyst-Free,Rapid Synthesis of Fused Bicyclic Thiazolo-Pyrimidine and Pyrimido-Thiazine Derivatives by a Microwave-Assisted Method

The present investigation deals with the rapid microwave-assisted synthesis of compounds containing fused bicyclic systems. Dihydropyrimidines obtained via a microwave-assisted Biginelli reaction were treated with dibromo alkanes under microwave conditions to yield thiazolo-pyrimidine and pyrimido-thiazine systems. The usefulness of this method lies in carrying out the reaction without a catalyst and solvent in a shorter time. The reaction was successfully extended to develop fused systems from benzimidazole-2-thiol.     

Cascade Wittig reaction-double Claisen and Cope rearrangements: one-pot synthesis of diprenylated coumarins gravelliferone, balsamiferone, and 6,8-diprenylumbelliferone

A cascade Wittig reaction-double Claisen and Cope rearrangements has been employed for a one-pot synthesis of diprenylated coumarins gravelliferone, balsamiferone, and 6,8-diprenylumbelliferone from a common precursor 2,4-diprenyloxybenzaldehyde.     

1‐Benzoyl‐3‐[(2‐benzylsulfanyl)phenyl]thiourea

In the title compound, C₂₁H₁₈N₂OS₂, a strong intramolecular N—H...O hydrogen bond [N...O = 2.642 (3) Å] between the amide N atom and the benzoyl O atom forms an almost planar six‐membered ring in the central part of the molecule. In the crystal, molecules are packed through weak N—H...S interactions. Intra‐ and intermolecular hydrogen bonds and van der Waals interactions are the stabilizing forces for the crystal structure.     

Ash of pomegranate peels (APP): A bio-waste heterogeneous catalyst for sustainable synthesis of α,α′-bis(substituted benzylidine)cycloalkanones and 2-arylidene-1-tetralones

Research on Chemical Intermediates - α,α′-bis(substituted benzylidene)cycloalkanones were efficiently prepared from variously substituted aldehydes and cycloalkanones in water by...     

Enhancement of green-light photoluminescence of Ta2O5 nanoblock stacks

In this study we have explored the structural, electronic, and photoluminescence (PL) properties of Ta(2)O(5) nanoblock stacks. The Ta(2)O(5) nanoblocks were synthesized by the hot filament metal-oxide vapor deposition (HFMOVD) technique and randomly arranged in large-area stacks. Field-emission scanning electron microscopy (FESEM) showed most of the stacking Ta(2)O(5) nanoblocks to be 21 nm wide. Energy dispersive spectroscopy (EDS) analysis verified the presence of only the elements Ta and O. X-Ray photoemission spectroscopy (XPS) not only revealed the electronic structures and chemical properties of the stacking Ta(2)O(5) nanoblocks but also their stoichiometric Ta/O ratio of ～0.416 (i.e. Ta:O = 2.08?:?5). Photoluminescence (PL) spectroscopy showed very strong green-light emissions, which emerged from the trap-levels of the oxygen vacancies within the Ta(2)O(5) bandgap. The PL intensities were linearly enhanced by increasing the laser power and the excitation time. The PL results suggest that the nanoblocks are excellent visible-light emitters.