Search Results (15)

The multicomponent synthesis of a novel and highly symmetric polyheterocycle based on the pyrrolo[3,4-b]pyridin-5-one core incorporating the privileged tetrahydroisoquinoline moiety is described. The target compound was synthesized as an inseparable mixture of stereoisomers through a pseudo-repetitive Ugi–Zhu five-component reaction (PR-UZ-5CR) coupled to a double post-transformation sequence involving an intermolecular aza Diels–Alder cycloaddition, an intramolecular N-acylation, and a final tandem aromatization step. The product was prepared in 63% overall yield, and with an excellent atom economy of 85%, within a total reaction time of 85 min, and a temperature range from 25 to 65 °C. Structural elucidation and molecular mass confirmation were successfully achieved through NMR and FT-IR spectroscopy, and high-resolution mass spectrometry (HRMS), respectively. Full article

The semi-synthesis of the (5R,7R,11bR)-9-(di(1H-indol-3-yl)methyl)-4,4,7,11b-tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodecahydrophenanthro[3,2-b]furan-5-yl acetate was performed via a pseudo-multicomponent reaction involving a double Friedel–Crafts alkylation between the natural product-derived aldehyde 6β-acetoxyvouacapane and the corresponding indole. The transformation was carried out under solvent-free mechanochemical conditions using mortar and pestle grinding, with ZnCl₂ as the catalyst. Structural elucidation of the target compound was accomplished using 1D and 2D NMR spectroscopy (¹H, ¹³C, COSY, HSQC, and HMBC), FT-IR, and high-resolution mass spectrometry (HRMS). Full article

A pseudo-multicomponent one-pot protocol for the synthesis of 1,3-disubstituted imidazolidin-2-one is described, employing trans-(R,R)-diaminocyclohexane for the in situ formation of the Schiff base, followed by reduction to produce the respective diamine and cyclization with carbonyldiimidazole (CDI). This approach utilizes statistical analysis to optimize the reaction conditions, allowing a pseudo-multicomponent protocol to be proposed. The developed method demonstrates sustainability, efficiency, and potential applications in green chemistry, achieving yields ranging from 55% to 81%. This represents a significant advance in synthesizing heterocyclic compounds with biological and pharmacological applications. Full article

Dialdehyde cellulose fabric (DACF) membranes with varying degrees of oxidation were fabricated using periodate oxidation and were employed for the chemical adsorption of amino-groups containing dyes from wastewater. The aldehyde group contents of DACF membranes were adjusted by altering oxidation time, which was confirmed by titration experiments. The chemical structure and morphology of DACF membranes were characterized using ATR-FTIR, TGA, SCA, SEM, XPS, and XRD measurements. The optimized DACF membrane, which was treated for an oxidation time of 24 h and has an aldehyde content of 2.97 mmol/g, was used for the chemical adsorption of amino-containing dye molecules. This process relies on the Schiff base reaction between the amino groups of the target dye molecule and the aldehyde groups of the membrane. Two typical cationic dyes, fuchsin basic and chrysoidine, containing aromatic amino groups, were chosen to determine the adsorption capacity of the DACF membrane. The adsorption kinetics, isotherms, and thermal dynamics of the DACF membrane were investigated comprehensively, while both pseudo-first- and pseudo-second-order kinetics models fit well, indicating the complicated chemical/diffusion adsorption process, where the hydrophobic properties of the DACF membrane retarded the adsorption rate. The maximum adsorption capacities of the DACF membrane against fuchsin basic and chrysoidine were 108.69 and 46.29 mg/g, respectively, as determined by Langmuir isotherm simulations. Various competing ions such as Na⁺, Ca²⁺, Cl⁻, and SO₄²⁻ at high concentrations of 10,000 ppm were used to challenge the adsorption capability of the DACF membrane, with negligible effects observed. A new adsorption mechanism based on chemical/diffusion interaction was proposed. Bovine serum albumin (BSA), fuchsin basic, and chrysoidine were mixed to simulate the multicomponent wastewater containing dissolved organic nitrogen (DON) and demonstrated the adsorption process; the direct adsorption capacity of the DACF membrane was up to 63.0%. This work offers a new method for the highly efficient removal of organic pollutants by a chemical reaction approach. Full article

The removal of contaminants from aqueous solutions by adsorption onto carbonaceous materials has attracted increasing interest in recent years. In this study, pristine and oxidized activated carbon (AC) fabrics with different surface textures and porosity characteristics were used for the removal of crystal violet (CV) dye from aqueous solutions. Batch adsorption experiments were performed to investigate the CV adsorption performance of the AC fabrics in terms of contact time, temperature, adsorbate concentration and adsorbent amount. Evaluation of the thermodynamic parameters and the adsorption performance of the AC fabrics in ground water and sea water solutions were also carried out. Langmuir isotherm model, pseudo first and pseudo second order kinetics models were utilized to analyze and fit the adsorption data. The introduction of oxygen-based functional groups on the surface of AC fabrics was carried out through a nitric acid treatment. This oxidation process resulted in a significant reduction in the surface area and pore volume, along with a small increase in the average pore size and a significant enhancement in the CV adsorption capacity, indicating that the dye molecules are mainly adsorbed on the external surface of the carbon fabrics. The herein evaluated 428 mg/g adsorption capacity at 55 °C for the oxidized non-woven AC fabric is one of the highest adsorption capacity values reported in the literature for CV removal using AC materials. Thermodynamic studies showed that the adsorption occurs spontaneously and is an endothermic and entropy-driven reaction. Furthermore, pristine and oxidized non-woven AC fabrics displayed more than 90% CV uptake from sea water samples, underlining the great potential these fabrics possess for the removal of dyes from natural/multicomponent waters. Full article

A one-pot multi-component reaction was employed for the stereoselective synthesis of a novel set of dispiro-oxindolopyrrolizidines analogs incorporating a thiazolo[3,2-a]benzimidazole scaffold based on the [3 + 2] cycloaddition (32CA) reaction approach. The desired novel dispiro-oxindolopyrrolizidines 9a–d were achieved using the 32CA reaction of new ethylene derivatives based on thiazolo[3,2-a]benzimidazole moiety seven with thiazolidine derivatives eight and different substituted isatin compounds 5a–d (R = H, Cl, NO₂, and Br). The final dispiro-oxindolopyrrolizidines cycloadducts were separated, purified, and fully characterized by means of a set of spectroscopic tools including IR, HNMR, CNMR, and MS. The Molecular Electron Density Theory (MEDT) was applied to explain the mechanism and stereoselectivity in the of the key 32CA reaction step. The reactive pseudo(mono)radical electronic structure of the in situ generated azomethine ylides and the high polar character of the corresponding 32CA reactions account for the low computed activation Gibbs free energies and total endo stereoselectivity of this kinetically controlled exergonic reaction. The computed relative Gibbs free activation energies of competitive reaction paths and regioisomers ratio distribution of 80:20 justify the major formation of 9a via the most favorable ortho/endo reaction path. Full article

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. Full article

To efficiently eliminate highly polar organic pollutants from water has always been a difficult issue, especially in the case of ultralow concentrations. Herein, we present the facile synthesis of quinolinecarboxylic acid-linked COF (QCA–COF) via the Doebner multicomponent reaction, possessing multifunction, high specific surface area, robust physicochemical stability, and excellent crystallinity. The marked feature lies in the quinolinyl and carboxyl functions incorporated simultaneously to QCA–COF in one step. The major cis–orientation of carboxyl arms in QCA–COF was speculated by powder X–ray diffraction and total energy analysis. QCA–COF demonstrates excellent adsorption capacity for water–soluble organic pollutants such as rhodamine B (255.7 mg/g), methylene blue (306.1 mg/g), gentamycin (338.1 mg/g), and 2,4–dichlorophenoxyacetic acid (294.1 mg/g) in water. The kinetic adsorptions fit the pseudo–second order model and their adsorption isotherms are Langmuir model. Remarkably, QCA–COF can capture the above four water–soluble organic pollutants from real water samples at ppb level with higher than 95% removal efficiencies and excellent recycling performance. Full article

The Ugi four-component reaction (Ugi-4CR) undoubtedly is the most prominent multicomponent reaction (MCRs) that has sparked organic chemists’ interest in the field. It has been widely used in the synthesis of diverse heterocycle molecules such as potential drugs, natural product analogs, pseudo peptides, macrocycles, and functional materials. The Ugi-4CRs involve the use of an amine, an aldehyde or ketone, an isocyanide, and a carboxylic acid to produce an α-acetamido carboxamide derivative, which has significantly advanced the field of isocyanide-based MCRs. The so-called intermediate nitrilium ion could be trapped by a nucleophile such as azide, N-hydroxyphthalimide, thiol, saccharin, phenol, water, and hydrogen sulfide instead of the original carboxylic acid to allow for a wide variety of Ugi-type reactions to occur.β In addition to isocyanide, there are alternative reagents for the other three components: amine, isocyanide, and aldehyde or ketone. All these alternative components render the Ugi reaction an aptly diversity-oriented synthesis of a myriad of biologically active molecules and complex scaffolds. Consequently, this review will delve deeper into alternative components used in the Ugi MCRs, particularly over the past ten years. Full article

Sulfonic resins are highly efficient cation exchangers widely used for metal removal from aqueous solutions. Herein, a new sulfonation process is designed for the sulfonation of algal/PEI composite (A*PEI, by reaction with 2-propylene-1-sulfonic acid and hydroxylamine-O-sulfonic acid). The new sulfonated functionalized sorbent (SA*PEI) is successfully tested in batch systems for strontium recovery first in synthetic solutions before investigating with multi-component solutions and final validation with seawater samples. The chemical modification of A*PEI triples the sorption capacity for Sr(II) at pH 4 with a removal rate of up to 7% and 58% for A*PEI and SA*PEI, respectively (with SD: 0.67 g L⁻¹). FTIR shows the strong contribution of sulfonate groups for the functionalized sorbent (in addition to amine and carboxylic groups from the support). The sorption is endothermic (increase in sorption with temperature). The sulfonation improves thermal stability and slightly enhances textural properties. This may explain the fast kinetics (which are controlled by the pseudo-first-order rate equation). The sulfonated sorbent shows a remarkable preference for Sr(II) over competitor mono-, di-, and tri-valent metal cations. Sorption properties are weakly influenced by the excess of NaCl; this can explain the outstanding sorption properties in the treatment of seawater samples. In addition, the sulfonated sorbent shows excellent stability at recycling (for at least 5 cycles), with a loss in capacity of around 2.2%. These preliminary results show the remarkable efficiency of the sorbent for Sr(II) removal from complex solutions (this could open perspectives for the treatment of contaminated seawater samples). Full article

The new bis-heterocyclic compound ferrocenyl-bis-(1-(4-benzyl-5-morpholinooxazol-2-yl)-N-(4-(trifluoromethyl)benzyl)methanamine) (1) was synthesized in 73% overall yield in 1.5 hours via a pseudo-repetitive Ugi-Zhu five-component reaction, starting from 1,1′-ferrocenedicarboxaldehyde, 4-(trifluoromethyl)benzylamine, and 2-isocyano-1-morpholino-3-phenylpropan-1-one, in 1:2.1:2.2 proportions, respectively, using scandium(III) triflate as a Lewis-acid catalyst, microwaves as a heat source, and toluene as a solvent. The synthesized compound was characterized by 1D (¹H, ¹³C, and ¹⁹F) and 2D (COSY, HSQC, and HMBC) NMR, HRMS, and FT-IR. Full article

Multicomponent reactions (MCRs) have inherent advantages in pot, atom, and step economy (PASE). This important green synthetic approach has gained increasing attention due to high efficiency, minimal waste, saving resources, and straightforward procedures. Presented in this review article are the recent development on 5-compoment reactions (5CRs) of the following six types: (I) five different molecules A + B + C + D + E; pseudo-5CRs including (II) 2A + B + C + D, (III) 2A + 2B + C, (IV) 3A + B + C, (V) 3A + 2B, and (VI) 4A + B. 5CRs with more than five-reaction centers are also included. Full article

In continuation of our recent research on the development of novel multicomponent reactions with isocyanides, we have used, for the first time, enols as the acid components in Ugi- and Passerini-type reactions. Thus, electron-poor pyrrolidinodiones react with aldehydes, amines, and isocyanides to give the enaminic four-component adducts. Conversely, in the absence of the amine component, careful control of the reaction conditions allows the involvement of one or two molecules of isocyanide to afford, selectively, either Passerini-type or pseudo-enol-Ugi-type products. These unprecedented condensations of isocyanides, aldehydes, amines, and 4-substituted pyrrolidine-2,3-diones constitute an excellent strategy for the preparation of new biologically relevant pyrrolidinones having peptidic or pseudo-peptidic groups on carbon 3. Full article

This study investigates the sorption of heavy metallic ions (HMIs), specifically lead (Pb²⁺), copper (Cu²⁺), iron (Fe³⁺), nickel (Ni²⁺) and zinc (Zn²⁺), by natural zeolite (clinoptilolite). These HMIs are combined in single-, dual-, triple-, and multi-component systems. The batch mode experiments consist of a total initial concentration of 10 meq/L normality for all systems, acidified to a pH of 2 by concentrated nitric (HNO₃) acid. A zeolite dosage of 4 g per 100 mL of synthetic nitrate salt aqueous solution is applied, for a contact period of 5 to 180 min. Existing kinetic models on HMIs sorption are limited for multi-component system combinations. Therefore, this study conducts kinetic analysis by both reaction and diffusion models, to quantify the sorption process. The study concludes that the process correlates best with the pseudo-second-order (PSO) kinetic model. In the multi-component system combining all five HMIs, the initial sorption rate and theoretical equilibrium capacity are determined as 0.0033 meq/g·min and 0.1159 meq/g, respectively. This provides significant insight into the mechanisms associated with the sorption process, as well as contributing to the assessment of natural zeolite as a sorbent material in its application in industrial wastewater treatment. Full article

The pseudo-four component click synthesis of dibenzylated 1,2,3-triazoles derived from aniline is reported. The cycloaddition of sodium azide to N-(prop-2-ynyl)-benzenamine (I) in the presence of equimolar amounts of p-substituted benzyl derivatives, yields a mixture of mono- and dibenzylated 1,2,3-triazoles. When two equivalents of the benzyl derivative are added to the multicomponent reaction, the selective preparation of the dibenzylated compounds is achieved. The reactivity of the aniline N-H bond in monobenzylated 1,2,3-triazoles was tested by treatment with one equivalent of a p-substituted benzyl chloride at 40 °C, rendering the dibenzylated derivatives quantitatively. Full article