Organic Reactions Research Articles

Emerging Aspects of Triazole in Organic Synthesis: Exploring its Potential as a Gelator.

Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) - commonly known as the "click reaction" - serves as the most effective and highly reliable tool for facile construction of simple to complex designs at the molecular level. It relates to the formation of carbon heteroatomic systems by joining or clicking small molecular pieces together with the help of various organic reactions such as cycloaddition, conjugate addition, ring-opening, etc. Such dynamic strategy results in the generation of triazole and its derivatives from azides and alkynes with three nitrogen atoms in the five-membered aromatic azole ring that often forms gel-assembled structures having gelating properties. These scaffolds have led to prominent applications in designing advanced soft materials, 3D printing, ion sensing, drug delivery, photonics, separation, and purification. In this review, we mainly emphasize the different mechanistic aspects of triazole formation, which includes the synthesis of sugar-based and non-sugar-based triazoles, and their gel applications reported in the literature for the past ten years, as well as the upcoming scope in different branches of applied sciences.

Mechanochemical and Microwave Multistep Organic Reactions

Abstract: The development of more sustainable chemical reactions and processes has been the focus of recent research activities. Advances in the field of organic synthesis have led to the emergence of new methodologies and techniques involving non-conventional energy sources. These include the applications of mechanical energy (mechanochemistry) and microwave radiation (MW) methods. This article reviews the advances in multistep organic synthesis of biologically relevant organic molecules using mechanochemistry and microwave techniques. Among them, various heterocyclic molecules (with nitrogen, oxygen, and sulphur atoms), amides, and peptides have been synthesized by multistep mechanochemical or MW reactions. Performing multiple synthetic steps using more sustainable methods shows cumulative advantages over multistep processes under conventional conditions in terms of reduced solvent use, shorter reaction times, better turnovers, and reaction yields. Simplification of protocols by carrying out two or more reaction steps in the same reaction vessel is another advantage of multistep syntheses.

Surfactants produced from carbohydrate derivatives: Part 2. A review on the value chain, synthesis, and the potential role of artificial intelligence within the biorefinery concept

AbstractThis comprehensive and critical review explores the synthesis and applications of carbohydrate‐based surfactants within the biorefinery concept, focusing on biobased sugar‐head molecules suitable for use across several manufacturing sectors, including cosmetics, pharmaceuticals, household products, detergents, and foods. The main focus relies on sustainable alternatives to conventional surfactants, which could reduce the final manufacturing carbon footprint of several industrial feedstocks and products. A thorough analysis of raw materials, highlighting the significance of feedstock sources, and the current biobased surfactants and rhamnolipid biosurfactants production trends, is presented. Key organic reactions for the production of sorbitan esters, sucrose esters, alkyl polyglycosides, and fatty acid glucamines, such as glycosidation, acylation, and etherification, as well as the production of rhamnolipids through fermentation are described. Given the scarce literature on the characterization of these surfactant types within the hydrophilic–lipophilic deviation (HLD) framework, the surfactant contribution parameter (SCP) in the HLD equation for sugar‐head surfactants is critically assessed. The economic landscape is also discussed, noting the significant growth in the biobased surfactants and biosurfactant market, driven by environmental awareness and regulatory changes, with projections indicating a substantial market increase in the forthcoming years. Finally, the promising potential of generative artificial intelligence (AI) in developing customized surfactant molecules, with optimized properties for targeted applications, is emphasized as a promising avenue for future research.

Construction of Cs2AgBiCl6/COF Heterojunction for Boosted Photocatalytic Thioester Oxidation.

Lead-free halide perovskites as a new kind of potential candidate for photocatalytic organic synthesis have attracted much attention recently. The rational heterojunction construction is regarded as an efficient strategy to delicately regulate their catalytic performances. Herein, a semi-conductive covalent organic framework (COF) nanosheet, C4N, is employed as the functional component to construct Cs2AgBiCl6/C4N (CABC/C4N) heterojunction. It is found that the C4N nanosheets with rich surface functional groups can serve as heterogeneous nucleation sites to manipulate the growth of CABC nanocrystals and afford close contact between each other, therefore facilitate the transfer and spatial separation of photogenerated charge carriers, as verified by in situ X-ray photoelectronic spectroscopy and Kelvin probe force microscopy. Moreover, the oxygen affinity of C4N endows the heterojunctions with outstanding aerobic reactivity, thus improving the photocatalytic performance largely. The optimal CABC/C4N heterojunction delivers a thioanisole conversion efficiency of 100% after 6h, which is 2.2 and 7.7-fold of that of CABC and C4N. This work provides a new ideal for the design and application of lead-free perovskite heterojunction photocatalysts for organic reactions.

Recent Advances in Denitrogenative Organic Transformations of 1,2,3‐Benzotriazin‐4(3H)‐ones

AbstractDenitrogenative organic transformations and related reactions are a class of significant approaches for carrying out unusual C−C/C‐heteroatom (C−O, C−N, C−S) bond‐forming reactions that are usually promoted by Ru, Ir, Pd, Ni, and Cu metal catalysts. In this trait, numerous methods were adopted to synthesize several pharmaceutically valuable N‐ and O‐containing heteroaromatics using 1,2,3‐benzotriazin‐4(3H)‐one as an electrophilic coupling partner. This review involves the recent achievements related to the metal/organo‐catalyzed thermal and visible‐light mediated denitrogenative approaches with 1,2,3‐benzotriazin‐4(3H)‐ones towards the synthesis of imperative N‐heteroaromatic compounds. In addition, metal and oxidant‐free ortho‐functionalization of benzotriazinones by using suitable nucleophilic partners have been discussed. In particular, the most novel methods employing Ni and Pd metal catalysts that have emerged are exhibited. Specific attention has been paid to offering the detailed mechanistic pathway to explain the role of metal catalysts and the mechanism in the absence of metal catalysts in the denitrogenative reactions under a thermal/visible light medium.

Combination of online hollow fiber liquid phase microextraction with smartphone-based sensing for in situ formaldehyde assay in fabric and wastewater samples.

A miniaturized analytical methodology was introduced based on the combination of a direct and online hollow fiber microextraction method with smartphone color detection. The method was used for the determination of formaldehyde (target analyte) in fabric and wastewater samples. In this regard, two reagents including ammonium acetate buffer and acetylacetone were added to the formaldehyde samples to create a colored compound. The colored compound was extracted from the sample by using the hollow fiber liquid-phase microextraction method, the extracted phase was not taken out of the extraction box and was directly transferred into a specially designed detection cell, and a smartphone was applied forin-situ color sensing and data readout. This combination gathered the advantages of both state-of-the-art microextraction techniques and smartphone sensing. Formaldehyde, as a carcinogenic compound widely used in paint and clothing industries, was selected as a model test. Factors affecting extraction efficiency were investigated and optimized, including the type of organic solvents, reagent concentration, salt, pH, stirring speed, reaction temperature, and extraction time. The linear region of the method under optimal conditions was 40-1500µg L-1 for wastewater samples and 0.3-11.2mg kg-1 for fabrics. The limit of detection and limit of qualification were 13 and 40µg L-1, respectively. The relative standard deviations for concentrations of 100 and 1000µg L-1 were 6% and 4%, respectively. To evaluate the application of the method for real samples, types of fabric and two samples of oil refinery wastewater were selected. The relative recovery in real samples was 84-98%. The results of the analytical parameters of the method show that the developed method can be used as an efficient method to determine formaldehyde in real samples.

Recent Developments of Nanostructured Photocatalysts Based on Semiconducting Chalcogenides for Organic Reactions

Abstract:: The earth-abundant metal chalcogenide is a highly versatile semiconductor with unique electronic and optical properties that seem to outperform the photocatalytic properties of metal oxides and metal nanoparticles. For ages, researchers are reaping the benefits of its photocatalytic properties in numerous reactions. However, the high charge recombination rates, poor compositional stability, and a smaller number of catalytically active sites restrict its application. The development of different kinds of heterojunctions by the combination of metal-chalcogenides with other conducting and semiconducting materials like metal oxides, metal nanoparticles, g-C3N4, single-atom catalysts, and MOF results in superior photocatalytic activity. This review provides insight into the various classes of metal-chalcogenide-based heterostructures and their application in various organic transformations. A brief overview of the synergistic properties arising from the development of such heterostructures helps to understand the surface interactions so that highly stable, efficient, and selective metal-chalcogenide-based heterostructures can be developed for industrially important photocatalytic organic transformations. This review also describes the role of mediators in boosting the stability and catalytic efficiency of the metal chalcogenides. Moreover, a thorough emphasis on the morphological impact of photocatalysts in various reactions will help with the development of metal chalcogenide heterostructures with tunable morphology and bandgap.

Synthesis of 8-Methoxy-1-Tetralone

Several methods have been developed for the synthesis of 8-methoxy-1- tetralone 4. The applications of some named organic reactions can be observed during the synthesis of tetralone 4. Attempts have been made to achieve the direct conversion of 5-methoxy-1-tetralone into the tetralone 4. The method for the ring expansion of tertiary cyclobutanol 30 catalyzed by silver salts has proved useful to obtain the title tetralone 4.

Analysis of undergraduate chemistry students’ responses to substitution reaction mechanisms: a road to mastery

Abstract This study analyzed third-year undergraduate Chemistry major students’ drawings and written explanations of substitution reactions. Seventy (70) students were purposively selected for this study. The main data collection instrument was a diagnostic test and students’ responses were analyzed using deductive coding. The study aimed to unearth students’ conceptual understanding and difficulties on substitution reactions to provide significant insights into improving teaching strategies and learning outcomes. The findings revealed that: 1. Students were more familiar with SN2 reaction mechanisms and could answer questions on SN2 reaction mechanisms better than SN1 reaction mechanisms; 2. Students’ use of ‘chemical vocabulary’ did not translate into an understanding of electron movement and causal mechanistic explanation; 3. About 97 % of the students who gave a correct/partially correct description provided a description of what was happening in the reaction without any further explanation of why the reaction occurred; 4. Students had a slightly better understanding of drawing the correct mechanisms than providing accurate explanations. This study recommends that, in teaching organic reaction mechanisms, instructors should emphasize on electron-pushing formalisms and explain how and why reactions occur to encourage mechanistic thinking in students. Also, students should be given ample practice in organic reaction mechanisms to improve mastery.

Conventional to “Go Green” Approach in Organic Reaction

In the recent times, the green method of chemical reactions becomes very popular. The scientists are now using the non–hazardous reagents and solvents to design a chemical reaction. The conventional method of most common organic rearrangements e.g Claisen, Fries etc and condensation reactions e.g Aldol, Benzoin, Knoevenegal etc. are designed successfully in greener approach. This article describes green approach of some of these reactions.

Computational and Spectroscopic Studies on the Formation of Halogen-Bonded Complexes Between Tertiary Amines and CBr4 and Application in the Light-mediated Amino Acid Coupling.

In recent years, halogen-bonded complexes (XBCs), in solution, have played a pivotal role in inducing photochemical organic reactions. In this work, we explore the ability of various tertiary amines to act as XB acceptors in the presence of the XB donor CBr4 by computational and spectroscopic studies. DFT studies clearly showcase the formation of XBCs between the studied tertiary amines and CBr4. Simultaneously, computational and experimental UV-Vis studies display intense red shifts that are consistent with charge transfer observed from tertiary amines to CBr4. A detailed NMR study revealed a clear chemical shift of the carbon carrying the bromine atoms upon mixing the XB acceptor with the donor, suggesting that this spectroscopic technique is indeed an experimental tool to identify the generation of XBCs. An application of the ability of such XBCs to activate a carboxylic acid under UVA irradiation or sunlight is presented for amino acid coupling. Among the various tertiary amines studied, the pair DABCO-CBr4 was found to work well for the photochemical amide bond formation. Direct infusion-HRMS studies allowed us to propose a general mechanism for the photochemical amino acid coupling in the presence of a tertiary amine and CBr4, initiated by the photoactivation of an XBC.

Self-Thermal Management in Filtered Selenium-Terminated MXene Films for Flexible Safe Batteries.

Li-ion batteries with superior interior thermal management are crucial to prevent thermal runaway and ensure safe, long-lasting operation at high temperatures or during rapid discharging and charging. Typically, such thermal management is achieved by focusing on the separator and electrolyte. Here, the study introduces a Se-terminated MXene free-standing electrode with exceptional electrical conductivity and low infrared emissivity, synergistically combining high-rate capacity with reduced heat radiation for safe, large, and fast Li+ storage. This is achieved through a one-step organic Lewis acid-assisted gas-phase reaction and vacuum filtration. The Se-terminated Nb2Se2C outperformed conventional disordered O/OH/F-terminated materials, enhancing Li+-storage capacity by ≈1.5 times in the fifth cycle (221 mAh·g-1 at 1 A·g-1) and improving mid-infrared adsorption with low thermal radiation. These benefits result from its superior electrical conductivity, excellent structural stability, and high permittivity in the infrared region. Calculations further reveal that increased permittivity and conductivity along the z-direction can reduce heat radiation from electrodes. This work highlights the potential of surface groups-terminated layered material-based free-standing flexible electrodes with self-thermal management ability for safe, fast energy storage.

Integrated Approach of Life Cycle Assessment and Experimental Design in the Study of a Model Organic Reaction: New Perspectives in Renewable Vanillin-Derived Chemicals.

This work is focused on performing a quantitative assessment of the environmental impacts associated with an organic synthesis reaction, optimized using an experimental design approach. A nucleophilic substitution reaction was selected, employing vanillin as the substrate, a phenolic compound widely used in the food industry and of pharmaceutical interest, considering its antioxidant and antitumoral potential. To carry out the reaction, three different solvents have been chosen, namely acetonitrile (ACN), acetone (Ace), and dimethylformamide (DMF). The syntheses were planned with the aid of a multivariate experimental design to estimate the best reaction conditions, which simultaneously allow a high product yield and a reduced environmental impact as computed by Life Cycle Assessment (LCA) methodology. The experimental results highlighted that the reactions carried out in DMF resulted in higher yields with respect to ACN and Ace; these reactions were also the ones with lower environmental impacts. The multilinear regression models allowed us to identify the optimal experimental conditions able to guarantee the highest reaction yields and lowest environmental impacts for the studied reaction. The identified optimal experimental conditions were also validated by experimentally conducting the reaction in those conditions, which indeed led to the highest yield (i.e., 93%) and the lowest environmental impacts among the performed experiments. This work proposes, for the first time, an integrated approach of DoE and LCA applied to an organic reaction with the aim of considering both conventional metrics, such as reaction yield, and unconventional ones, such as environmental impacts, during its lab-scale optimization.

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.