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Pseudo-multicomponent reactions (Pseudo-MCRs) have led to a variety of compounds with interesting biological properties, especially desirable in the pharmaceutical industry. The isatin nucleus could be considered a privileged scaffold for the design of biologically active substances. Dimedone is an interesting and versatile molecule for most organic transformations, especially one-pot and multicomponent reactions. Xanthene derivatives are still an attractive research field for both academia investigations and industry. In this investigation, a simple and efficient tandem Knoevenagel–Michael protocol with subsequent cyclization for the synthesis of the previously unknown 4a′-hydroxy-3′,3′,5,6′,6′,7-hexamethyl-3′,4′,4a′,6′,7′,9a′-hexahydrospiro[indole-3,9′-xanthene]-1′,2,8′(1H,2′H,5′H)-trione was elaborated. The suggested method is based on the pseudo-MCR of 5,7-dimethylisatin and dimedone. The structure of the earlier unknown compound was proven using 1H, 13C-NMR, and IR spectroscopy, mass spectrometry, and elemental analysis. To compare the developed protocol with the existing ones, unsubstituted spiro[indole-3,9′-xanthene] was synthesized. Its structure has been proven using two-dimensional (2D) NMR spectroscopy techniques. [ABSTRACT FROM AUTHOR]

In recent years, the application of privileged structures has become a powerful approach in the discovery of new biologically active molecules. Ion pairing is a strategy used to enhance the permeation of ionized topical drugs. A convenient and efficient method for the synthesis of triethylammonium 2-(3-hydroxy-2-oxoindolin-3-yl)-5,5-dimethyl-3-oxocyclohex-1-en-1-olate has been developed. The presented protocol includes an aldol reaction and the formation of an ammonium salt. Triethylamine is both a reactant and a catalyst in the process. The structure of the synthesized title compound has been established by 1H, 13C-NMR and IR spectroscopy, mass spectrometry, and elemental analysis. [ABSTRACT FROM AUTHOR]

Novel cyano-benzylidene xanthene derivatives were synthesized using one-pot and condensation reactions. A diprotic Brønsted acid (i.e., oxalic acid) was used as an effective catalyst for the promotion of the synthesis process of the new starting xanthene–aldehyde compound. Different xanthene concentrations (ca. 0.1–2.0 mM) were applied as corrosion inhibitors to control the alkaline uniform corrosion of aluminum. Measurements were conducted in 1.0 M NaOH solution using Tafel extrapolation and linear polarization resistance (LPR) methods. The investigated xanthenes acted as mixed-type inhibitors that primarily affect the anodic process. Their inhibition efficiency values were enhanced with inhibitor concentration, and varied according to their chemical structures. At a concentration of 2.0 mM, the best-performing studied xanthene derivative recorded maximum inhibition efficiency values of 98.9% (calculated via the Tafel extrapolation method) and 98.4% (estimated via the LPR method). Scanning electron microscopy (SEM) was used to examine the morphology of the corroded and inhibited aluminum surfaces, revealing strong inhibitory action of each studied compound. High-resolution X-ray photoelectron spectroscopy (XPS) profiles validated the inhibitor compounds' adsorption on the Al surface. Density functional theory (DFT) and Monte Carlo simulations were applied to investigate the distinction of the anticorrosive behavior among the studied xanthenes toward the Al (111) surface. The non-planarity of xanthenes and the presence of the nitrile group were the key players in the adsorption process. A match between the experimental and theoretical findings was evidenced. [ABSTRACT FROM AUTHOR]

A new magnetic supported manganese-based coordination complex (Fe3O4@SiO2@CPTMS@MBOL@ Mn) was prepared in consecutive stages and characterized via various techniques (VSM, SEM, TEM, XRD, FT-IR, EDX, TG-DTA, and ICP). To evaluate its application, it was used for synthesis of divers Indazolophthalazinetriones in a simple procedure via the one-pot three-component condensation reaction of aldehydes, dimedone, and phthalhydrazide in ethanol under reflux conditions. The Mn catalyst can be recycled without any noticeable loss in catalytic activity. Additionally, the antibacterial properties of the nano-catalyst were studied against some bacterial strains. [ABSTRACT FROM AUTHOR]

The title compound 9-(4-hydroxybutyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro- 1H-xanthene-1,8(2H)-dione was synthesized in 72% yield through a simple, convenient and environmentally friendly one-pot reaction between dimedone and 3,4-dihydro-2H-pyran in aqueous citric acid. Additionally, a plausible reaction mechanism for the formation of the target xanthene is proposed. [ABSTRACT FROM AUTHOR]

Symmetrical and non-symmetrical diimines derived from dimedone were synthesized by the reaction of their corresponding enaminothiones with primary amines. The synthesized compounds were characterized using micro analytical data and NMR spectroscopy. Theoretical calculations by B3LYP/6-31G(d,p) level of theory show that the enolic form is the most stable within the possible tautomeric forms of the compounds. [ABSTRACT FROM AUTHOR]

A facile and convenient protocol was developed for the fast (2.5-3.5 h) and high yielding (70-90 %) synthesis of fused 1,4-dihydropyridines from dimedone in the presence of HY-zeolite as an efficient recyclable heterogeneous catalyst. [ABSTRACT FROM AUTHOR]

A simple and highly efficient protocol for the synthesis of derivatives 7, 7-dimethyl-4-phenyl-2-thioxo-2, 3, 4, 6, 7, 8-hexahydro-1H-quinazoline-5-one from 5, 5-dimethyl cyclohexane-1, 3-dione (4a–4h) (dimedone) has been described. The aryl aldehydes were substituted with thiourea in the presence of synthesized zinc ferrite nanocatalyst, which increased the yield under reflux through condensation, followed by cyclization to give desired products. The other advantages are that it is eco-friendly and economically affordable for large-scale production. Structural validation and characterization of all the newly synthesized compounds were evaluated by spectral analysis (mass spectrometry, proton nuclear magnetic resonance (1HNMR), and Carbon-13 nuclear magnetic resonance(13CNMR)spectroscopies. The structure of antibacterial and antifungal assays was performed with the newly synthesized compounds. The antimicrobial activity of title compounds possessing electron-withdrawing groups such as (4e–4h) (Cl, Br, and cyano group) exhibited more active potential than the electron-donating groups, C6H5,4-C6H4, 3-OC2H5-4OH-C6H3, etc., (4a–4d) containing moiety. [ABSTRACT FROM AUTHOR]

Glutathione-based products, GSnX, of the reaction of hydrogen sulfide, H2S, S-nitroso glutathione, and GSNO, at varied stoichiometries have been analyzed by liquid chromatography high-resolution mass spectrometry (LC-HRMS) and chemical trapping experiments. A wide variety of glutathione-based species with catenated sulfur chains have been identified including sulfanes (GSSnG), sulfides (GSSnH), and sulfenic acids (GSnOH); sulfinic (GSnO2H) and sulfonic (GSnO3H) acids are also seen in reactions exposed to air. The presence of each species of GSnX within the original reaction mixtures was confirmed using Single Ion Chromatograms (SICs), to demonstrate the separation on the LC column, and given approximate quantification by the peak area of the SIC. Further, confirmation for different GSnX families was obtained by trapping with species-specific reagents. Several unique GSnX families have been characterized, including bridging mixed di- and tetra-valent polysulfanes and internal trithionitrates (GSNHSnH) with polysulfane branches. Competitive trapping experiments suggest that the polysulfane chains are formed via the intermediacy of sulfenic acid species, GSSnOH. In the presence of radical trap vinylcyclopropane (VCP) the relative distributions of polysulfane speciation are relatively unaffected, suggesting that radical coupling is not a dominant pathway. Therefore, we suggest polysulfane catenation occurs via reaction of sulfides with sulfenic acids. [ABSTRACT FROM AUTHOR]