Preparation of benzo[4,5]thiazolo[3,2-a]chromeno[4,3-d]pyrimidin-6-one derivatives using MgO-MgAl2O4 composite nano-powder

Revisiting Biginelli-like reactions: solvent effects, mechanisms, biological applications and correction of several literature reports

This study critically reevaluates reported Biginelli-like reactions using a Kamlet-Abboud-Taft-based solvent effect model. Surprisingly, structural misassignments were discovered in certain multicomponent reactions, leading to the identification of pseudo three-component derivatives instead of the expected MCR adducts. Attempts to replicate literature conditions failed, prompting reconsideration of the described MCRs and proposed mechanisms. Electrospray ionization (tandem) mass spectrometry, NMR, melting points, elemental analyses and single-crystal X-ray analysis exposed inaccuracies in reported MCRs and allowed for the proposition of a complete catalytic cycle. Biological investigations using both pure and "contaminated" derivatives revealed distinctive features in assessed bioassays. A new cellular action mechanism was unveiled for a one obtained pseudo three-component adduct, suggesting similarity with the known dihydropyrimidinone Monastrol as Eg5 inhibitors, disrupting mitosis by forming monoastral mitotic spindles. Docking studies and RMSD analyses supported this hypothesis. The findings described herein underscore the necessity for a critical reexamination and potential corrections of structural assignments in several reports. This work emphasizes the significance of rigorous characterization and critical evaluation in synthetic chemistry, urging a careful reassessment of reported synthesis and biological activities associated with these compounds.

Alkyl ammonium hydrogen sulfate immobilized on Fe3O4@SiO2 nanoparticles: a highly efficient catalyst for the multi-component preparation of novel tetrazolo[1,5-a]pyrimidine-6-carboxamide derivatives

In this, a three-component reaction for the preparation of novel tetrazolo[1,5-a]pyrimidine-6-carboxamide derivatives from N,N'-(sulfonylbis(1,4-phenylene))bis(3-oxobutanamide), aldehydes and 1H-tetrazol-5-amine is reported. The application of Fe3O4@SiO2-(PP)(HSO4)2 (A) as a catalyst afforded the desired products (a1-a18) in high yields in DMF as solvent as well as under solvent-free conditions.

Synthetic Methods for Various Chromeno-fused Heterocycles and their Potential as Antimicrobial Agents

Chromenes are a significant family of heterocyclic chemicals that have a wide range of biological applications, a simple chemical structure, and only mildly undesirable side effects. The synthesis of a wide range of chromene analogs that displayed unexpected behaviors via numerous mechanisms was investigated by a number of different research teams, which led to the discovery of multiple pathways for their synthesis. In addition, different chromene-fused heterocycles exhibit a wide variety of fascinating biological actions, including those that are anticancer, anticonvulsant, antibacterial, anticholinesterase, antituberculosis, and anti-diabetic. In light of this, the purpose of this study is to highlight the many synthesis techniques and antibacterial activity associated with chromene-fused heterocyclic compounds. Moreover, such research can open avenues for exploring other therapeutic applications of these compounds in various disease areas, as their biological activities extend beyond antibacterial effects.

A Sulfonic Acid Polyvinyl Pyridinium Ionic Liquid Catalyzes the Multi-Component Synthesis of Spiro-indoline-3,5'-pyrano[2,3-d]-pyrimidines and -Pyrazines

A sulfonated poly-4-vinyl pyridinium (PVPy-IL-B-SO₃H) containing an acidic pyridinium/HSO₃^- ionic liquid moiety was prepared and used as a catalyst for the three-component reaction of malononitrile with 1-alkylindoline-2,3-diones and 1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione or methyl 5-hydroxy-1H-pyrazole-3-carboxylate, leading to methyl 6'-amino-5'-cyano-2-oxo-2'H-spiro[indoline-3,4'-pyrano[2,3-c]pyrazole]-3'-carboxylates or -3,4'-pyrano[2,3-d]pyrimidine]-6'-carbonitrile derivatives under ultrasonic irradiation conditions. The solid catalyst allows easy separation, is cheap, produces high yields under mild conditions, and does not require column chromatography for product isolation and purification.

Preparation of some chromeno[4,3-d]pyrido[1,2-a]pyrimidine derivatives by ultrasonic irradiation using NiFe2O4@SiO2 grafted di(3-propylsulfonic acid) nanoparticles

NiFe₂O₄@SiO₂ grafted di(3-propylsulfonic acid) was prepared by a facile method and characterized by XRD, FT-IR, SEM-EDX, TGA, and BET techniques.