Search

Organic frameworks face a trade‐off between the framework stability and the bond dynamics, which necessitates the development of innovative linkages that can generate stable frameworks without hindering efficient synthesis. Although iodine(I)‐based halogen‐bonded organic frameworks (XOFs) have been developed, constructing XOFs based on bromine(I) is desirable yet challenging due to the high sensitivity of bromine(I) species. In this work, we present the inaugural construction of stable bromine(I)‐bridged two‐dimensional (2D) halogen‐bonded organic frameworks, XOF(Br)−TPy−BF4/OTf, based on sensitive [N⋅⋅⋅Br⋅⋅⋅N]+ halogen bonds. The formation of XOF(Br)−TPy−BF4/OTf was monitored by 1H NMR, XPS, IR, SEM, TEM, HR‐TEM, SEAD. Their framework structures were established by the results from PXRD, theoretical simulations and SAXS. More importantly, XOF(Br) displayed excellent chemical and thermal stabilities. They exhibited stable two‐dimensional framework structures in various organic solvents and aqueous media, even over a wide pH range (pH 3–12), while the corresponding model compounds BrPy2BF4/OTf decomposed quickly even in the presence of minimal water. Furthermore, the influence of the counterions were investigated by replacing BF4 with OTf, which improved the stability of XOF(Br). This characteristic enabled XOF(Br) to serve as an efficient oxidizing reagent in aqueous environments, in contrast with the sensitivity of BrPy2BF4/OTf, which performed well only in organic media. This study not only deepens our fundamental understanding of organic frameworks but also opens new avenues for the development and application of multifunctional XOFs. [ABSTRACT FROM AUTHOR]

Enone reduction by ene‐reductase (ERED) has not been reported yet in bulk organic media probably due to expected challenges with the cofactor recycling using a second enzyme and the exchange of the NAD(P)‐cofactor between the two enzymes. Herein, the combination of an ERED from Zymomonas mobilis (NCR‐ERED) and Thermoanaerobacter ethanolicus alcohol dehydrogenase (TeSADH) has been found as an efficient biocatalytic redox system for the reduction of cyclohex‐2‐enone into cyclohexanol in bulk organic solvents. Both enzymes were successfully immobilised on three EziG supports, finding Coral as the most promising carrier for both of them. The highest enzymatic activities were found in hydrophobic solvents such as toluene and isooctane. It was observed that the control of water content and post‐immobilisation treatments enabled retention of enzyme activity. Both enzymes were co‐immobilised on the same bead together with NADP+, leading to the production of a self‐sufficient catalytic system, although the external supplementation of the nicotinamide cofactor was necessary for an efficient enzyme reuse. In this case, no ERED activity loss was detected after two additional cycles, while the ADH experienced less than 20 % activity loss upon reuse. [ABSTRACT FROM AUTHOR]

The synthesis of sulfoxides has long attracted considerable interest due to their pivotal role in organic synthesis, pharmaceutics and environmental protection. Oxidation of the corresponding sulfides is recognized as the most effective strategy. Traditional oxidation methods, however, fall short of the growing demands of green chemistry. Photocatalytic aerobic oxidation has thus garnered attention, employing the greenest and most sustainable oxidants—oxygen or air—and sunlight as the energy source. Nevertheless, these reactions are typically conducted in potentially pollutive organic solvents rather than in the greenest solvent, water. To facilitate this organic transformation in aqueous phase, molecular reactors that can encapsulate reactants within their confined pores and facilitate photocatalytic reactions have been developed recently. This Concept article summarizes the development of molecular reactors for the photocatalytic oxidation of sulfides and provides perspectives for the design and construction of effective photocatalytic molecular reactors. [ABSTRACT FROM AUTHOR]

Conducting electrochemical organic synthesis in/on whole water media is undoubtedly a highly green approach, which avoids the usage of organic solvents, and sometimes organic supporting electrolytes. In this review, the electrochemical organic syntheses in/on whole water environment are reviewed, especially including the reactions conducted both in organic solvent and water for comparisons. This review discussed anodic and cathodic reaction, respectively, including the C−H oxidation, hydroxylation, dehydrogenative cross coupling, functionalization of alkenes, cathodic oxidation, hydrogenation, reductive cross coupling, and so on. As the reduction of CO2, conversion biomass, and waste water disposal are frequently performed in water, and have already been reviewed recently. These topics are not included in this review. [ABSTRACT FROM AUTHOR]

This study uses a rapid tandem mass‐spectrometry method to determine water content in complex organic solutions. Emphasis is placed on trace‐water analysis by a fast and accurate alternative to the Karl–Fischer method. In this new method, water is captured by a charge‐labeled molecular probe. Water binds strongly with high specificity to the strongly electrophilic aldehyde site in a charge‐labelled molecule (N‐methylpyridinium); competitive binding by other analytes is effectively discriminated against in the mass‐measurement step. Quantitative determinations are made over a wide concentration range, 0.001 % (10 ppm) to 99 %, with better than 10 % relative standard deviation, along with short (1 min) analysis times using small sample volumes (several μL). Applications include water measurement in simple organic solvents, for example, deuterated solvents, as well as in complex mixtures, for example, organic reaction mixtures. Additionally, this method allows for water monitoring in levitated droplets. Mechanistic investigations into the impact of water on important chemical processes in organic synthesis and environmental science are reported. [ABSTRACT FROM AUTHOR]

Biocatalysis has been an emerging field in organic synthetic chemistry in recent years and has significantly expanded the application of enzymes. Further, the concept of enzymatic promiscuity, where an enzyme catalyzes reactions beyond its natural function, has been recognized as a valuable phenomenon that can enhance the versatility of an enzyme as a biocatalyst. Recent advancements in organic synthesis, driven by the demand for more efficient and environmentally friendly processes, have led to the development of enzyme‐catalyzed multicomponent reactions such as Biginelli reaction, Hantzsch synthesis, Mannich, Ugi, etc. for the synthesis of N‐Heterocyclic compounds. While a number of enzymes have played an important role in this context, lipase enzyme is still indispensable due to its low cost, easy availability, and higher organic solvent tolerance. In particular, the immobilization of lipase enzyme on various supports enhances its stability, reusability, and efficiency in catalyzing organic transformation, which expands its role beyond traditional biocatalytic methods. In this review, we have mainly compiled the findings that highlight the synthetic applications of lipases in manufacturing several types of N‐containing heterocyclic compounds. [ABSTRACT FROM AUTHOR]

The use of volatile solvents for organic synthesis is nowadays questioned due to their negative impact on the environnement. To develop sustainable and environmentally friendly methodologies, we propose to combine two green chemistry concepts: the use of bioinspired solvents: natural deep eutectic solvents (NaDES), and mechanochemistry. Using the Suzuki‐Miyaura coupling as a model reaction, we described an efficient mechanochemical method with NaDES as a LAG (liquid‐assisted grinding) additive with short reaction times and without any ligand or additional heating. A mechanochemical extraction was also used to reduce the amounts of extraction solvents and the total time of the synthesis process. [ABSTRACT FROM AUTHOR]

Multicomponent reactions are crucial for operating organic synthesis. In today's world, chemists concentrate on greener methodologies that cater to rising environmental concerns. Most conventional organic solvents are harsh on the environment, which can be addressed by environmentally and pocket‐friendly Deep eutectic solvents (DES). Organic synthesis via MCR in the presence of DES has resulted in the blend of green methodology and green solvent for organic transformations. Forasmuch as addressing the environmental concerns and developing higher heterocycles, our review focuses on the literature published on the DES‐mediated Multicomponent synthesis of N‐Heterocyclic compounds. [ABSTRACT FROM AUTHOR]

Green chemistry is the basis for fast‐growing, eco‐friendly, alternative sustainable technologies for the development of chemical products without the use or generation of hazardous catalysts. The role of naturally occurring fruit juice as a catalyst or solvent in organic synthesis has gained focused interest across the globe. Lemon juice‐mediated synthesis has been widely explored recently as a highly significant, selective solvent and biocatalyst in organic synthesis. This review presents recent developments on lemon‐juice mediated transformations and their application to synthesize molecules or building blocks of pharmaceutical interest. We believe this review article will be of interest to researchers both in academic and industrial settings focused on developing novel pharmacophores from a green chemistry principles perspective. [ABSTRACT FROM AUTHOR]

Imines are important intermediates in drug synthesis. Photocatalytic aerobic oxidative coupling of amines has been considered as a clean and promising way to produce imines and has attracted great attention. Herein, we designed and synthesized a novel two‐dimensional porphyrin‐based covalent organic framework (Por‐BC‐COF) which adopts an AA stacking mode with excellent crystallinity, high Brunauer–Emmett–Teller surface areas (1200 m2 g−1), wide light absorption range (200–1300 nm) and good stability in a variety of organic solvents. Por‐BC‐COF can be used as a metal‐free heterogeneous photocatalyst for the photocatalytic oxidation of amines to imines under visible light and red light with a high yield (97 %). This work presents a novel and efficient COF photocatalyst in the application of light‐driven organic synthesis. [ABSTRACT FROM AUTHOR]

In the last twenty years, N‐heterocyclic carbenes (NHCs) have been extensively studied for their application as organocatalysts in stereoselective synthesis as well as ligands for transition metals‐promoted synthetic methodologies. Derived mainly from azolium salts, NHCs have demonstrated exceptional versatility in their generation usually performed by deprotonation or reduction (chemical or electrochemical). In particular, the generation of NHC under electrochemical conditions, starting from azolium‐based ionic liquids, has proven to be a successful green approach and demonstrated wide applicability in organic synthesis. In this Personal Account, the application of electrogenerated NHCs in organic synthesis will be discussed, with a particular attention to the different reactivity in ionic liquids compared to classical organic solvents. [ABSTRACT FROM AUTHOR]

Separation and purification on molecular level from organic solvent mixtures are of paramount importance in industries. Organic solvent nanofiltration (OSN) is a pressure‐driven membrane separation process providing an attractive alternative to conventional energy‐intensive technologies. However, devising a solvent stable, scalable membrane with high permeability and excellent selectivity is still a challenge. Interfacially polymerized thin‐film composite (TFC) OSN membranes integrating an ultrathin selective layer and a porous substrate layer are expected to revolutionize advanced membrane separations. New materials and new strategies to achieve a solvent resistant, highly permeable, and highly selective membrane have been developed in recent years. This review analyses the development of the state‐of‐the‐art interfacially polymerized TFC OSN membranes from the view of structures, materials, and methodologies. First, the emerging structures of current TFC OSN membranes are discussed. The exploitation of new materials (polymers, (nano)fibers, inorganic materials) for the preparation of substrate layer is updated. The advances of new aqueous/organic monomers for synthesis of the selective layer are summarized. Furthermore, the proposed strategies for designing permselective TFC membranes are highlighted. Finally, the challenges together with the future prospects of interfacially polymerized TFC membranes for OSN are proposed. [ABSTRACT FROM AUTHOR]

Microemulsions are clear, stable, isotropic mixtures of oil, water, and surfactant, frequently in combination with a cosurfactant. These systems are currently of interest to the pharmaceutical scientist because of their considerable potential to act as drug delivery vehicles by incorporating a wide range of drug molecules. The purpose of this work is to solubilize in AOT [sodium bis(2‐ethylhexyl)sulphosuccinate] water‐in‐oil microemulsions at two different R‐values the Chromobacterium viscosum (CV) lipase and lipoprotein lipase ex Pseudomonas and to use them to catalyze the lactonization of 16‐hydroxyhexadecanoic acid at 40°C. CV lipase is also immobilized in gelatin‐containing microemulsion‐based gels (MBGs) with retention of catalytic activity. These lipase‐containing MBGs proved to be novel solid‐phase catalysts for use in apolar organic solvents. CV lipase‐containing MBGs are used to synthesize, on a preparative scale, a variety of different esters under mild conditions. [ABSTRACT FROM AUTHOR]

Adaptation of all‐in‐one ionic systems with ionic liquids (ILs) serving as solvent, reactant, and catalyst is an innovative approach in the organic synthesis. Mild and bio clean choline based ILs as all‐in‐one systems (solvent, reagent, and catalyst) were developed via a simple metathesis approach and were applied on the ring‐opening reaction of epoxides. Sustained transformation of various epoxides using choline cyanide, azide, and hydroxide ILs delivered a neat, efficient and convenient protocol for the synthesis of β‐substituted alcohols in moderate to high yields (64‐97 %) with excellent activity and selectivity as confirmed by nuclear magnetic resonance (NMR) spectroscopic data. [ABSTRACT FROM AUTHOR]

In these environmentally conscious days there is need to use eco‐friendly greener technologies, such as solvent free, microwave, ultrasound and use of room temperature. Here report an efficient and green protocol for the synthesis of 5‐aminopyrazole‐4‐carbonitrile from three component condensation of phenyl hydrazine, aldehyde, and malononitrile using NaPTS as catalyst in aqueous medium. Use of water has emerged as a versatile solvent for organic reaction; it is readily available, inexpensive, environmentally benign, neutral and natural solvent. Multicomponent reactions in water are of outstanding value in organic synthesis and green chemistry. The significant features of this article are short reaction time, provide excellent yield, removal of toxic solvent and use of water as green solvent. [ABSTRACT FROM AUTHOR]

Designing reactions in aqueous media has been one of the major challenges in modern organic synthesis, especially to avoid the use of large amounts of organic solvents whose disposal is a matter of grave concern from an environmental perspective. The oxidation of alcohols and amines is an essential and important step in the synthesis of many valuable products including polymers and pharmaceuticals. In recent times, there has been a surge in the use of water as a solvent in many organic reactions. This review focuses specifically on the oxidation reactions of alcohols and amines carried out in water media using transition metal catalysts, metal‐free catalysts and photocatalysts. [ABSTRACT FROM AUTHOR]

The main objective of this study was to replace the traditionally applicable volatile organic solvents and imidazolium‐based ionic liquid solvents with thermally stable surfactant, cetylpyridinium bromide as surfactant ionic liquid (SIL) and examine the potential of the same as viable reaction medium in the synthesis of stilbenes, quinoxaline and pyridone decorated substrates via Heck cross‐coupling reaction. This work thoroughly investigates the thermal, spectral and morphological properties of cetylpyridinium bromide as surfactant ionic liquid. Cetylpyridinium bromide is a well‐known germicide with well‐established degradation mechanism and displays remarkable solvent properties for the homogeneously catalysed Heck cross‐coupling reactions, which is of great significance to enlarge the applications window of cetylpyridinium bromide from biologically significant surfactant material to the choice of solvent in synthetic organic chemistry. [ABSTRACT FROM AUTHOR]

A series of 8‐azacoumarin, naphthyridine, and dioxazphenalene derivatives bearing conjugated moieties were intended and prepared by a concise and smooth approach using grinding and ultrasonic irradiation. A sustainable one pot reactions have emerged and progressed smoothly as an efficient and eco‐safe methods in solvent less organic synthesis. The desired products were obtained in high yields, and the structures of all products were established on the basis of spectroscopic data and elemental analysis. Using the density functional theory (DFT) realized the electronic and structure characterization of synthesized azacoumarin. These heterocyclic compounds are chemically stable and are tested as antioxidants. Antioxidant potential was assessed using ABTS, and anti‐hemolytic activity was evaluated by induced peroxide hemolysis. They gave good antioxidant results that showed potency ranging from good azacoumarin analogues 8, 9, 13, 17, and 20, among compounds, showed much potency than that of commercial ascorbic acid. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increasing tendency to use biocatalysts in industrial chemistry, especially in the pharma and fine chemical sector. Preferably, enzymes or whole cells, applied as catalysts for a specific biotransformation, are utilized in aqueous reaction media since water is the natural medium for enzymes. In numerous examples of biocatalytic systems, however, a major problem is the insolubility of hydrophobic substrates in such aqueous reaction media. Apart from lipases, many enzymes are highly sensitive to organic solvents and are inactivated by an organic medium. Therefore, a change of solvent for biotransformations from water to organic solvents is usually challenging. In this study, we investigated the synthesis of nitriles by an organic solvent‐labile aldoxime dehydratase in pure organic solvents, exemplified for the dehydration of n‐octanaloxime to n‐octanenitrile. We present a method for applications in batch as well as flow mode based on an "immobilized aqueous phase" bearing the whole cells in a superabsorber as solid phase, thus enabling the use of a purely organic solvent as "mobile phase" and reaction medium. [ABSTRACT FROM AUTHOR]

A series of issues have been caused by the extensive use of volatile and toxic organic solvents in organics and polymers synthesis, i. e. increased production costs and irreversible damage to the environment. Hence, it is necessary to pioneer a synthesis method that is green, safe, and efficient to the sustainable development of society. Herein, a facile and controllable, but rational and effective, in situ solid‐phase synthesis method was developed to prepare a silica‐templated Fe‐phthalocyanine‐based porous organic polymer (POP), which can be further converted into an iron and nitrogen codoped porous carbon (HS‐Phth‐Fe‐900) upon carbonization and template removal. This innovative approach simultaneously provides a means to control the surface features, thereby tuning the catalytic property of obtained materials. The final HS‐Phth‐Fe‐900 with hierarchical pore structure exhibits hollow hemispheric morphology, large pore volume and surface area, significantly improving the mass transfer efficiency and promoting the accessibility of the active sites, achieving a high oxygen reduction reaction (ORR) activity in alkaline media (0.1 M KOH). HS‐Phth‐Fe‐900 presents a competitive half‐wave potential of 0.823 V and limiting current of 4.887 mA/cm2 (vs. 0.833 V and 5.621 mA cm−2 for Pt/C) far beyond the catalysts prepared free of template (Phth‐Fe‐900). Furthermore, it also exhibits long‐time stability and methanol immunity surpassing the benchmark Pt/C in 0.1 M KOH. These results may open up new possibilities for the rational design and large‐scale preparation of POPs‐derived materials for electrochemical applications. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) of CdSe have been produced with high yield using common reagents in water at 150 °C. The QDs thus produced are water compatible, show intense fluorescence emission and have high quantum yields (QYs). Their size can be controlled similarly to the high temperature organometallic method of synthesizing QDs, and these QDs produced in organic solvents at high temperature and the QDs produced in water both show comparable QYs. The great advantage is that a green solvent, water, is used and their separation from the water is very simple. They can be stored dry very easily. Similar to the organic method their size can be controlled by time, producing QDs with distinct fluorescence. The size obtained by TEM for 30, 60 and 90 minutes of reaction is 4.18 nm, 6.7 nm and 8.6 nm, respectively. This parallels the change in the emission wavelength of the QDs produced; green, yellow and orange, respectively. TEM dimensions are very similar to these of DLS (dynamic light scattering). These QDs display the hexagonal wurtzite phase, common for the higher temperature synthesis of QDs in organic solvents, and not the zinc blende phase of CdSe QDs common for the lower temperature water synthesis of QDs. The prepared QDs have shown the same intense emission for over a year after being synthesized. [ABSTRACT FROM AUTHOR]

Front Cover: FeIII-Based Eutectic Mixtures as Multi-task and Reusable Reaction Media for Efficient and Selective Conversion of Alkynes into Carbonyl Compounds (Chem. Eur. J. 57/2023) Keywords: alkynes; atom economy; deep eutectic solvents; FeCl3-mediated organic synthesis; hydration EN alkynes atom economy deep eutectic solvents FeCl3-mediated organic synthesis hydration 1 1 1 10/18/23 20231013 NES 231013 B Thanks to the use b of a sustainable Fe SP III sp -based deep eutectic solvent ( I DES i ) as promoter/reaction medium, alkynes were hydrated under bench-type reaction conditions (45 °C, air, absence of co-catalysts or co-solvents). Alkynes, atom economy, deep eutectic solvents, FeCl3-mediated organic synthesis, hydration. [Extracted from the article]

Organic synthesis without an organic solvent is still the exception. In this microreview, we discuss and compare different synthetic methods that proceed in the absence of conventional organic solvents. This includes solvent‐free methods in solids (mechanochemistry and solid‐state photochemistry), and in neat liquids (thermal and photocatalytic), as well as the application of unconventional solvents, such as ionic liquids and deep‐eutectic solvents. The different approaches are briefly introduced and examples illustrate their specific advantages, followed by a critical discussion of their limitations. Some methods have the intrinsic benefits of solvent‐free operation, such as avoiding solubility problems and side‐reactions with the solvent. However, every method has specific advantages and the demand of the synthetic application is crucial for selecting the best technique. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) acting as new functional solvents have significant impact in both synthetic and materials chemistry. However, the usage of volatile organic solvents in both synthesis and recycling of ILs usually imposes environmental issues. In this study, according to intrinsic wetting threshold theory, a membrane-based approach assisted by superwettability is developed for efficient, convenient, and economical purification of water-immiscible ILs. By precisely tailoring surface energy, the porous membrane is capable of hydrophobicity and superILphilicity (defined as IL contact angle close to zero), selectively allowing ILs to pass through. This kind of functional membrane can not only separate IL/water mixtures, but also IL/water systems containing inorganic salts, organic compounds, amino acids, and proteins. [ABSTRACT FROM AUTHOR]

This microreview summarizes the use of deep eutectic solvents (DESs) and related melts in organic synthesis. Solvents of this type combine the great advantages of other proposed environmentally benign alternative solvents, such as low toxicity, high availability, low inflammability, high recyclability, low volatility, and low price, avoiding many disadvantages of the more modern media. The fact that many of the components of these mixtures come directly from nature assures their biodegradability and renewability. The classification and distribution of the reactions into different sections in this microreview, as well as the emphasis paid to their scope, easily allow a general reader to understand the actual state of the art and the great opportunities opened, not only for academic purposes but also for industry. [ABSTRACT FROM AUTHOR]

Monovalent RAl (R = HC[C(Me)N(2,6-iPr2C6H3)]2) reacts with E2Et4 (E = Sb, Bi) with insertion into the weak E--E bond and subsequent formation of RAl(EEt2)2 (E = Sb 1; Bi 2). The analogous reactions of RGa with E2Et4 yield a temperature-dependent equilibrium between RGa-(EEt2)2 (E = Sb 3; Bi 4) and the starting reagents. RIn does not interact with Sb2Et4 under various reaction conditions, but formation of RIn(BiEt2)2 (5) was observed in the reaction with Bi2Et4 at low temperature. [ABSTRACT FROM AUTHOR]

Review: 106 refs. [ABSTRACT FROM AUTHOR]

Antibacterial activity is observed for new styrenesulfonamides (III) against Gram-positive Staphylococcus aureus, with compounds (IIIc,d) being the most effective ones. [ABSTRACT FROM AUTHOR]

Review: 110 refs. [ABSTRACT FROM AUTHOR]