Organic Reactions Research Articles

An inexpensive, metal-free and one-pot approach towards N-sulfonyl amidines: Identification of a chorismate mutase inhibitor with activities against S. aureus

The simple yet innovative synthetic approaches for the direct access to the diversity based unique class of compounds of potential biological interest are of considerable interest as that can greatly facilitate the efforts in bioorganic / medicinal chemistry and drug discovery. In our efforts, we have developed a metal-free, inexpensive and one-pot method for the facile and direct synthesis of N-sulfonyl amidines that were designed as inhibitors of chorismate mutase. The methodology involved POCl3-SOCl2 promoted reaction of amide with sulphonamide to afford an array of new and unique class of compounds in good to acceptable yields. The methodology is free from the use of additional organic reaction media and amenable for scale-up. Based on in vitro and in silico studies, 3g has been identified as a first example of chorismate mutase inhibitor with selective and promising activities on a range of S. aureus strains. Indeed, the docking of 3g into AlphaFold predicted structure S. aureus CM I (UniProt ID: A0A380DU97) revealed good interactions with stabilization mostly via π-anion interactions in addition to a halogen (fluorine) bond. Compound 3g is of further pharmacological interest.

Influence of physical and water quality parameters on residual chlorine decay in water distribution network

Chlorine is the most common disinfectant in drinking water distribution practice. World Health Organization recommends 0.2–5.0 mg/l of residual chlorine in drinking water. This paper analyzed influence of physical and water quality parameters on chlorine decay in drinking water distribution. Principal component analysis, directed tree and regression were used to investigate influence of these parameters on chlorine from water treatment plant to water consumption points. Results show that initial chlorine, electrical conductivity and distance explain 62 % of chlorine decay with estimated error of 0.045 mg/l. The decision-tree feature importance scores of initial chlorine and electrical conductivity were 0.47 and 0.23 respectively. The combined feature importance scores of physical parameters of distance (0.09), pipe diameter (0.06), flow velocity (0.03), pressure (0.02) and travel time (0.046) were less than that for initial chlorine concentration (0.47) alone. These results show that conventional chlorination at water treatment plants removes largely fast inorganic reactants leaving traces of slow organic reactants as the dominant secondary contaminants in water distribution system. The key policy recommendation is to use water quality parameters more than physical parameters in order to enable water utility managers maintain residual chlorine within safe public health standards.

Synthesis and density functional theory study of functionalized Oxazolidine-2-ones using a novel MnFe2O4@SiO2-SiO3H magnetic nanocatalyst

This study introduces MnFe2O4@SiO2-SiO3H as a novel magnetic catalyst and thoroughly investigates its structure, catalytic activity, and reusability. The synthesis of the magnetic catalyst was meticulously characterized using an array of analytical techniques. Utilizing MnFe2O4@SiO2-SiO3H, the synthesis of functionalized oxazolidine-2-ones were performed, versatile compounds widely employed in chiral auxiliaries, protecting groups, and medicinal chemistry. Remarkably, the two-step process from chalcones demonstrated one of the shortest reported pathways, highlighting the efficiency of our novel nanocatalyst. To elucidate the stability and reactivity of the synthesized products, we employed Density Functional Theory (DFT) calculations, including molecular electrostatic potential (MEP) mapping and reactivity indices such as electronegativity, electrophilic index, softness, and hardness, as well as frontier molecular orbitals (HOMO-LUMO). Furthermore, our investigations extended to the recycling capabilities of the nanocatalyst. Through a comprehensive evaluation of at least five reaction cycles, MnFe2O4@SiO2-SiO3H showcased a remarkable retention of activity (97–92 %), reaffirming its reusability and long-term potential. Our research presents MnFe2O4@SiO2-SiO3H as a highly effective and recoverable nanomagnetic catalyst for organic reactions, with demonstrated applications in synthesizing functionalized oxazolidine-2-ones. As such, our findings offer a promising alternative to traditional methods, presenting new opportunities in catalysis and materials science.

Synthesis of p-phenylene-based chiral dicarboxamides via aminocarbonylation of 1’,4-diiodostyrene

Chiral p-phenylene-based dicarboxamides featuring carboxamide and 2-arylacrylamide motifs were synthesised through a synthetic sequence involving conventional organic reactions followed by palladium-catalysed aminocarbonylation. 4-Iodoacetophenone was used as starting material to prepare to 1’,4-diiodostyrene, which underwent several aminocarbonylation reactions, using in situ formed palladium-phosphine catalysts and various biologically relevant amines as N-nucleophiles such as, amino acid esters, nortropine, and aminoandrostane derivatives. By exploring the remarkable difference in reactivity between the iodoalkene and iodoarene functionalities, the aminocarbonylation of the iodoalkene moiety was carried first with high chemoselectivity, followed by sequential transformation of the iodoarene functionality into the corresponding carboxamide using a different nucleophile. This approach allowed us to obtain a range of otherwise challenging chiral dicarboxamides, in moderate to high isolated yields through highly chemoselective reactions.

Direct de/carboxylation of cannabidiolic acid (CBDA) and cannabidiol (CBD) from hemp plant material under supercritical CO2

Many organic reactions rely on CO2 sources to generate important structural units and valuable chemicals. In this study, we compared the effects of cannabidiol (CBD) and cannabidiolic acid (CBDA) on the supercritical CO2 (scCO2)-induced de/carboxylation reaction. The results showed that CBD was directly carboxylated in the ortho-position to form CBDA with up to 62% conversion. Meanwhile, CBDA decarboxylation occurred on hemp plant material via varying composition. Mechanistic studies revealed that CBD carboxylation was influenced not only by the physical properties of scCO2, but also by the vegetable matrix.

Electrochemical oxidation of concentrated benzyl alcohol to high-purity benzaldehyde via superwetting organic-solid-water interfaces.

Organic electrosynthesis in aqueous media is presently hampered by the poor solubility of many organic reactants and thus low purity of liquid products in electrolytes. Using the electrooxidation of benzyl alcohol (BA) as a model reaction, we present a "sandwich-type" organic-solid-water (OSW) system, consisting of BA organic phase, KOH aqueous electrolyte, and porous anodes with Janus-like superwettability. The system allows independent diffusion of BA molecules from the organic phase to electrocatalytic active sites, enabling efficient electrooxidation of high-concentration BA to benzaldehyde (97% Faradaic efficiency at ~180 mA cm-2) with substantially reduced ohmic loss compared to conventional solid-liquid systems. The confined organic-water boundary within the electrode channels suppresses the interdiffusion of molecules and ions into the counterphase, thus preventing the hydration and overoxidation of benzaldehyde during long-term electrocatalysis. As a result, the direct production of high-purity benzaldehyde (91.7%) is achieved in a flow cell, showcasing the effectiveness of electrocatalysis over OSW interfaces for the one-step synthesis of high-purity organic compounds.

Efficient Radical-Mediated Intermolecular α-Alkylation Reactions of Carbonyl Compounds with Nonactivated Alkenes.

Alkylation reactions are fundamental carbon-carbon bond-forming reactions in synthetic organic chemistry. Among them, intermolecular α-alkylation reactions of carbonyl compounds with alkenes are important because they are more atom-economical than the equivalent processes using alkyl halides. However, intermolecular reactions with nonactivated alkenes such as 1-hexene, which can allow the use of a wide range of valuable substrates, have been considered to be very challenging for a long time. In this review, radical-mediated intermolecular α-alkylation reactions of carbonyl compounds with nonactivated alkenes are discussed. The examples are grouped into three types of reactions: peroxide-mediated reactions, metal-oxidant-mediated reactions, and photoactivated reactions. Photoredox-catalyzed alkylation reactions under visible-light irradiation are discussed as a particularly promising recent hot topic. This review provides brief history and new prospects on the α-alkylation process with nonactivated alkenes using α-carbonyl radical species.

Preparation of Magnetic Nano-Catalyst Containing Schiff Base Unit and Its Application in the Chemical Fixation of CO2 into Cyclic Carbonates

The development of a catalyst for the conversion of CO2 and epoxides to the corresponding cyclic carbonates is still a very attractive topic. Magnetic nano-catalysts are widely used in various organic reactions due to their magnetic separation and recycling properties. Here, a magnetic nano-catalyst containing a Schiff base unit was designed, synthesized and used as a heterogeneous catalyst to catalyze CO2 and epoxides to form cyclic carbonates without solvents and co-catalysts. The catalyst was characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric (TG), VSM, SEM, TEM and BET. The results show that the magnetic nano-catalyst containing the Schiff base unit has a high activity in the solvent-free cycloaddition reaction of CO2 with epoxide under mild conditions, and is easily separated from the reaction mixture driven by external magnetic force. The recovered catalyst maintains a high performance after five cycles.

ChatGPT Convincingly Explains Organic Chemistry Reaction Mechanisms Slightly Inaccurately with High Levels of Explanation Sophistication

ChatGPT Convincingly Explains Organic Chemistry Reaction Mechanisms Slightly Inaccurately with High Levels of Explanation Sophistication

Leveraging tannic acid-ferric iron (TA/Fe3+) complexation in polyamide selective layer for synthesizing robust thin film composite reverse osmosis (TFC-RO) hollow fiber membranes for saline water treatment

The high efficiency and adaptability of reverse osmosis (RO) are two main reasons this separation technology is accepted worldwide, depending on its various uses, such as water purification, desalination, and concentration. The potential of RO can be enhanced by utilizing the hollow fiber (HF) mode, benefiting from higher packing density, ease of cleaning, and cost competitiveness. However, its suitability for RO applications becomes questionable due to its weaker and fragile mechanical resilience. To solve the abovementioned issue and improve the mechanical strength and burst/crush pressure, we propose optimizing the selective layer of the TFC-RO membrane using tannic acid complexation with FeCl3. The polyethersulfone (PES) support layer was initially fabricated to host the polyamide (PA) layer. Subsequently, the introduction of tannic acid-ferric chloride complexation was implemented as a sandwich layer between the aqueous and organic phase reactions to host a coherent and selective PA layer to further enhance its performance by controlling the kinetics of interfacial polymerization (IP). The surface morphology, physicochemical properties, and underlying reactions were analyzed using scanning electron microscopy (SEM), atomic force microscope (AFM), Fourier infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS), and water contact angle measurements. The TFC-RO membrane M_TA0.2/Fe7.5 (7.5 mM FeCl3 & 0.2 wt% tannic acid) showed significant improvement in pure water permeance and salt rejection along with 7.23 MPa of burst pressure and 68.41 % strain, which proves superior elasticity and mechanical robustness because of PA TA/Fe3+ complexes formed during the IP. Moreover, the proposed facile tannic acid modification is effective and scalable. It significantly improves the mechanical efficacy of the HF TFC-RO membrane, solving a great problem for its commercial adaptability for RO applications and paving the way for smoother industrial translation for direct human factor applications.

Silica Nanoparticles Functionalized with an Ionic Liquid: A Green and Efficient Heterogeneous Catalyst for a Cascade Reaction

AbstractA new strategy for a catalytic C−C bond forming cascade reaction comprising acetal hydrolysis and Knoevenagel condensation is presented here. The heterogeneous nanocatalyst is prepared by immobilizing an ionic liquid on the surface of highly monodisperse silica nanoparticles. This work is the first example of showing that there is no need to use bifunctional acid‐base catalysts for a cascade reaction including the hydrolysis of benzaldehyde dimethyl acetal to benzaldehyde and the subsequent Knoevenagel condensation of the resulting benzaldehyde with malononitrile. It is shown here that these reactions can proceed smoothly with a mono‐functional heterogeneous catalyst that contains a neutral ionic liquid. It has been proposed that such a neutral ionic liquid can “switch on” to an acidic catalyst in conjunction with water. The selected ionic liquid has potentially biodegradability characteristics, which is an important issue to achieve a sustainable catalyst. The simple procedure for preparing both the ionic liquid and the monodisperse silica nanoparticles provides opportunities for a large‐scale synthesis of the catalyst. This work introduces a breakthrough in the design and synthesis of heterogeneous catalysts for acid/base catalyzed cascade organic reactions.

CuCl2/FeCl3 Bimetallic Photocatalyst for Sustainable Ethylene Production from Ethanol via Recoverable Redox Cycles.

Photocatalytic conversions of ethanol to valuable chemicals are significant organic synthesis reactions. Herein, we developed a CuCl2/FeCl3 bimetallic photocatalyst for sustainable dehydration of ethanol to ethylene by recoverable redox cycles. The selectivity of ethylene was 98.3% for CuCl2/FeCl3, which is much higher than that of CuCl2 (34.5%) and FeCl3 (86.5%). Due to the ligand-to-metal charge transfer (LMCT) process involved in generating the liquid products, the CuCl2/FeCl3 catalyst will be reduced to CuCl/FeCl2. Oxygen (O2) is required for the recovery of CuCl2/FeCl3 to avoid exhaustion. The soluble Fe3+/Fe2+ redox species deliver catalyst regeneration properties more efficiently than single metal couples, making a series of redox reactions (Cu2+/Cu+, Fe3+/Fe2+, and O2/ethanol couples) recyclable with synergistic effects. A flow reactor was designed to facilitate the continuous production of ethylene. The understanding of bimetallic synergism and consecutive reactions promotes the industrial application process of photocatalytic organic reactions.

Practical Three-Component Regioselective Synthesis of Drug-Like 3-Aryl(or heteroaryl)-5,6-dihydrobenzo[h]cinnolines as Potential Non-Covalent Multi-Targeting Inhibitors To Combat Neurodegenerative Diseases.

Neurodegenerative diseases (NDs) are one of the prominent health challenges facing contemporary society, and many efforts have been made to overcome and (or) control it. In this research paper, we described a practical one-pot two-step three-component reaction between 3,4-dihydronaphthalen-1(2H)-one (1), aryl(or heteroaryl)glyoxal monohydrates (2a-h), and hydrazine monohydrate (NH2NH2•H2O) for the regioselective preparation of some 3-aryl(or heteroaryl)-5,6-dihydrobenzo[h]cinnoline derivatives (3a-h). After synthesis and characterization of the mentioned cinnolines (3a-h), the in silico multi-targeting inhibitory properties of these heterocyclic scaffolds have been investigated upon various Homo sapiens-type enzymes, including hMAO-A, hMAO-B, hAChE, hBChE, hBACE-1, hBACE-2, hNQO-1, hNQO-2, hnNOS, hiNOS, hPARP-1, hPARP-2, hLRRK-2(G2019S), hGSK-3β, hp38α MAPK, hJNK-3, hOGA, hNMDA receptor, hnSMase-2, hIDO-1, hCOMT, hLIMK-1, hLIMK-2, hRIPK-1, hUCH-L1, hPARK-7, and hDHODH, which have confirmed their functions and roles in the neurodegenerative diseases (NDs), based on molecular docking studies, and the obtained results were compared with a wide range of approved drugs and well-known (with IC50, EC50, etc.) compounds. In addition, in silico ADMET prediction analysis was performed to examine the prospective drug properties of the synthesized heterocyclic compounds (3a-h). The obtained results from the molecular docking studies and ADMET-related data demonstrated that these series of 3-aryl(or heteroaryl)-5,6-dihydrobenzo[h]cinnolines (3a-h), especially hit ones, can really be turned into the potent core of new drugs for the treatment of neurodegenerative diseases (NDs), and/or due to the having some reactionable locations, they are able to have further organic reactions (such as cross-coupling reactions), and expansion of these compounds (for example, with using other types of aryl(or heteroaryl)glyoxal monohydrates) makes a new avenue for designing novel and efficient drugs for this purpose.

Single-Atom Iron Catalyst as an Advanced Redox Mediator for Anodic Oxidation of Organic Electrosynthesis.

Homogeneous electrocatalysts can indirect oxidate the high overpotential substrates through single-electron transfer on the electrode surface, enabling efficient operation of organic electrosynthesis catalytic cycles. However, the problems of this chemistry still exist such as high dosage, difficult recovery, and low catalytic efficiency. Single-atom catalysts (SACs) exhibit high atom utilization and excellent catalytic activity, hold great promise in addressing the limitations of homogeneous catalysts. In view of this, we have employed Fe-SA@NC as an advanced redox mediator to try to change this situation. Fe-SA@NC was synthesized using an encapsulation-pyrolysis method, and it demonstrated remarkable performance as a redox mediator in a range of reported organic electrosynthesis reactions, and enabling the construction of various C-C/C-X bonds. What's more, Fe-SA@NC demonstrated a great potential in exploring new synthetic method for organic electrosynthesis. We em-ployed it to develop a new electro-oxidative ring-opening transformation of cyclopropyl amides. In this new reaction system, Fe-SA@NC showed good tolerance to drug molecules with complex structures, as well as enabling flow electrochemical syntheses and gram-scale transformations. This work highlights the great potential of SACs in organic electrosynthesis, thereby opening a new avenue in synthetic chemistry.

Single‐Atom Iron Catalyst as an Advanced Redox Mediator for Anodic Oxidation of Organic Electrosynthesis

Homogeneous electrocatalysts can indirect oxidate the high overpotential substrates through single‐electron transfer on the electrode surface, enabling efficient operation of organic electrosynthesis catalytic cycles. However, the problems of this chemistry still exist such as high dosage, difficult recovery, and low catalytic efficiency. Single‐atom catalysts (SACs) exhibit high atom utilization and excellent catalytic activity, hold great promise in addressing the limitations of homogeneous catalysts. In view of this, we have employed Fe‐SA@NC as an advanced redox mediator to try to change this situation. Fe‐SA@NC was synthesized using an encapsulation‐pyrolysis method, and it demonstrated remarkable performance as a redox mediator in a range of reported organic electrosynthesis reactions, and enabling the construction of various C‐C/C‐X bonds. What's more, Fe‐SA@NC demonstrated a great potential in exploring new synthetic method for organic electrosynthesis. We em‐ployed it to develop a new electro‐oxidative ring‐opening transformation of cyclopropyl amides. In this new reaction system, Fe‐SA@NC showed good tolerance to drug molecules with complex structures, as well as enabling flow electrochemical syntheses and gram‐scale transformations. This work highlights the great potential of SACs in organic electrosynthesis, thereby opening a new avenue in synthetic chemistry.

The use of drama in A Level chemistry: a study into the effects of simulation-role-play on the quality of learning of organic reaction mechanisms

ABSTRACT Background Much of the research into the use of drama in science education has been qualitative, with its primary focus being on its affective value amongst students aged 6–14 years, with a smaller fraction on effectiveness in terms of academic achievement and understanding of chemistry amongst older school students (16–18 years). Purpose This article reports on a study that compared the effectiveness of drama, as a pedagogy, with a didactic practice-examinations-questions-based approach on students’ understanding of chemistry organic reaction mechanisms as measured by examination question scores. Sample Data were collected in seven 11–18 schools and a Further Education (FE) college in England, with a total of 236 students, aged 16–18 years, studying Advanced (A) Level chemistry. Each institution had two different classes studying chemistry concurrently. Design and methods The research was a quasi-experimental intervention with one class of A Level chemistry students in each institution being taught an aspect of organic reaction mechanisms using drama and the second, non-drama, class being taught the same material using practice examination questions. Post-intervention, all students completed previously unseen A Level examination questions and, in one phase of the study, a diagnostic question designed to probe deeper understanding. The responses were subject to statistical analysis. Results In all cases there were no statistically significant differences between the test scores of the two groups for the answers to the examination questions. However, answers to a diagnostic question, probing deep level understanding, showed a statistically significant difference between the two groups in favour of the drama group. Conclusions Whilst drama is at least as effective as the use of practice examination questions in the teaching and learning of organic reaction mechanisms it was statistically significantly more effective in terms of the development of deeper level conceptual understanding.

Artificial Photosynthases: Single-Chain Nanoparticles with Manifold Visible-Light Photocatalytic Activity for Challenging "in Water" Organic Reactions.

Photocatalyzed reactions of organic substances in aqueous media are challenging transformations, often because of scarce solubility of substrates and catalyst deactivation. Herein, we report single-chain nanoparticles, SCNPs, capable of efficiently catalyzing four different "in water" organic reactions by employing visible light as the only external energy source. Specifically, we decorated a high-molecular-weight copolymer, poly(OEGMA300-r-AEMA), with iridium(III) cyclometalated complex pendants at varying content amounts. The isolated functionalized copolymers demonstrated self-assembly into noncovalent, amphiphilic SCNPs in water, which enabled efficient visible-light photocatalysis of two reactions unprecedentedly reported in water, namely, [2 + 2] photocycloaddition of vinyl arenes and α-arylation of N-arylamines. Additionally, aerobic oxidation of 9-substituted anthracenes and β-sulfonylation of α-methylstyrene were successfully carried out in aqueous media. Hence, by merging metal-mediated photocatalysis and SCNPs for the fabrication of artificial photoenzyme-like nano-objects─i.e., artificial photosynthases (APS)─our work broadens the possibilities for performing challenging "in water" organic transformations via visible-light photocatalysis.

Revealing the Critical Role of Global Electron Density Transfer in the Reaction Rate of Polar Organic Reactions within Molecular Electron Density Theory.

The critical role of global electron density transfer (GEDT) in increasing the reaction rate of polar organic reactions has been studied within the framework of Molecular Electron Density Theory (MEDT). To this end, the series of the polar Diels-Alder (P-DA) reactions of cyclopentadiene with cyanoethylene derivatives, for which experimental kinetic data are available, have been chosen. A complete linear correlation between the computed activation Gibbs free energies and the GEDT taking place at the polar transition state structures (TSs) is found; the higher the GEDT at the TS, the lower the activation Gibbs free energy. An interacting quantum atoms energy partitioning analysis allows for establishing a complete linear correlation between the electronic stabilization of the electrophilic ethylene frameworks and the GEDT taking place at the polar TSs. This finding supports Parr's proposal for the definition of the electrophilicity ω index. The present MEDT study establishes the critical role of the GEDT in the acceleration of polar reactions, since the electronic stabilization of the electrophilic framework with the electron density gain is greater than the destabilization of the nucleophilic one, making a net favorable electronic contribution to the decrease in the activation energy.

A Stoichiometric Haloform Coupling for Ester Synthesis with Secondary Alcohols.

The haloform reaction from methyl ketones to carboxylic acids is one of the oldest known synthetic organic reactions, which has been used in myriad applications over the decades. The corresponding reaction to produce esters is, however, less developed, as the reaction is generally limited to simple, primary alcohols that are used in solvent-level quantities, thereby restricting the complexity of esters that can be directly formed. Herein, we detail the development of a general ester-forming haloform coupling reaction using one equivalent of alcohol. Mechanistic and kinetic modelling studies demonstrated that the key intermediates are formed under equilibrium, which facilitated the development of conditions that are amenable to secondary alcohols.

A Stoichiometric Haloform Coupling for Ester Synthesis with Secondary Alcohols

AbstractThe haloform reaction from methyl ketones to carboxylic acids is one of the oldest known synthetic organic reactions, which has been used in myriad applications over the decades. The corresponding reaction to produce esters is, however, less developed, as the reaction is generally limited to simple, primary alcohols that are used in solvent‐level quantities, thereby restricting the complexity of esters that can be directly formed. Herein, we detail the development of a general ester‐forming haloform coupling reaction using one equivalent of alcohol. Mechanistic and kinetic modelling studies demonstrated that the key intermediates are formed under equilibrium, which facilitated the development of conditions that are amenable to secondary alcohols.