Carbonyl Research Articles

Ka-Band Rotational Spectroscopy of Succinimide and N-Chlorosuccinimide.

Succinimide and its derivatives are cyclic five-membered rings that appear in a variety of natural products and are widely used in organic synthesis. From a structural standpoint, succinimide contains an NH group in the ring which interacts with two adjacent carbonyl groups, pushing the ring structure toward planarity at the expense of increasing ring strain and eclipsing interactions among the out-of-plane hydrogen atoms in the two CH2 groups. Previous quantum chemical calculations at different levels of theory have predicted both a nonplanar C2 structure and a planar C2v structure, the latter of which is the most consistent with gas-phase electron diffraction measurements. Here, we report the pure rotational spectra of succinimide and N-chlorosuccinimide in the 26.5-40.0 GHz range using chirped-pulse Fourier transform microwave spectroscopy, supported by coupled cluster and density functional theory quantum chemical calculations. The spectra were fit to Watson's A-reduced effective Hamiltonian, including both 35Cl and 37Cl isotopologues of N-chlorosuccinimide as well as the N and Cl quadrupole hyperfine interactions. On the basis of the agreement with quantum chemical calculations and the measured inertial defects, we find that the rotational spectra are consistent with a planar ring structure, with a maximum out-of-plane angle of ≤5°.

3,4-Dihalo-5-hydroxy-2(5H)-furanones: Highly Reactive Small Molecules.

3,4-Dichloro-5-hydroxy-2(5H)-furanone and its dibromo analog are highly reactive molecules. Both are members of the 2(5H)-furanone family, which are important as pharmacophores present in drugs and natural products. Compounds possessing the 2(5H)-furanone skeleton isolated from plants and marine organisms exhibit bioactivity against various microorganisms and viruses and can also be used in other medical treatments. The structures of these 3,4-dihalo-2(5H)-furanones cause their high reactivity due to the presence of a carbonyl group on the C2 carbon conjugated with a double bond and a hydroxyl group on the C5 carbon. Two labile halogen atoms on carbons 3 and 4 offer additional possibilities for the introduction of other substituents. These structural features make 3,4-dihalo-5-hydroxy-2(5H)-furanones versatile reactants in chemical synthesis. In this review, we present methods of 3,4-dihalo-5-hydroxy-2(5H)-furanone synthesis, their applications as substrates in various chemical transformations, and examples of their biologically active derivatives.

Direct C3−H Alkylation and Alkenylation of Quinolines with Enones

AbstractConversion of quinoline C−H bonds into C−C bonds is essential for obtaining the enormous array of derivatives required for pharmaceutical and agrochemical development. Despite over a century of synthetic efforts, direct alkylation and alkenylation at C3−H positions in a wide array of quinoline precursors remain predominantly challenging and elusive. This report outlines the first successful quinoline C3−H alkylation and alkenylation reactions, exhibiting exceptional regio‐ and stereoselectivity, all achieved under redox‐neutral and transition‐metal‐free conditions. The method involves a three‐step, one‐pot or two‐pot sequence, including 1,4‐dearomative addition, functionalization at C3, and elimination or transalkylation to produce 3‐alkylated/alkenylated quinolines. The presence of a carbonyl group in these products allows for further synthetic manipulations, enabling the production of cyanides, amides, amines, and simple alkyl derivatives.

Antidiabetic potential of Lavandula stoechas aqueous extract: insights into pancreatic lipase inhibition, antioxidant activity, antiglycation at multiple stages and anti-inflammatory effects.

With the increasing global prevalence of type 2 diabetes (T2D) and obesity, there is a pressing need for novel therapeutic interventions. Lavandula stoechas, a medicinal plant traditionally used for various ailments, holds promise as a potential agent for T2D management, particularly in Morocco, where it is commonly used to treat diabetes. This study aims to evaluate the pharmacological potential of L. stoechas aqueous extract (AqLs) by assessing its lipase inhibition antioxidant and anti-inflammatory activities, identifying phenolic compounds, and examining its efficacy in reducing diabetic complications. The pharmacological potential of L. stoechas aqueous extract was investigated using in vitro assays. The inhibitory effect on pancreatic lipase, antioxidant power (FRAP), and anti-inflammatory activity (albumin denaturation method) was assessed. High-performance liquid chromatography (HPLC) analysis identified phenolic compounds. Additionally, albumin glycation was evaluated by estimating fructosamine, carbonyl groups, and amyloid β-structures to assess efficacy in mitigating diabetic complications. The extract demonstrated concentration-dependent inhibition of pancreatic lipase (IC50 = 0.132 ± 0.006mg/mL), potent antioxidant activity (IC50 = 604.99 ± 1.01μg/mL), and dose-dependent anti-inflammatory effects (IC50 = 207.01 ± 34.94mg/mL). HPLC analysis revealed phenolic compounds: naringin (38.28%), syringic acid (25.72%), and cinnamic acid (15.88%) were the most abundant, with 4-hydroxybenzoic acid, hydrated catechin, and catechin ranging from 9.60% to 5.24%, and p-coumaric acid (1.73%). Furthermore, the extract inhibited albumin glycation and fructosamine production, suggesting efficacy in mitigating diabetic complications. These findings highlight the multifaceted pharmacological potential of L. stoechas aqueous extract in T2D management, suggesting that this plant can be highly beneficial for diabetic individuals.

Local Oxygen Reconstruction Enables Dual‐Ion Active Sites in Carbon Cathode for High Energy Density Sodium‐Ion Capacitors

AbstractCarbon materials are the promising cathode material for sodium‐ion capacitors (SICs) with high energy/power density, however, clarifying the evolution processes of functional groups in carbon materials and revealing their energy storage mechanisms are full of challenges. Inspired by the ancient practice of alchemy, which sought to purify Dan medicine and remove impurities through precise control of the refining temperature, the local oxygen reconstruction strategy, to alter the functional groups species in SP3‐C, is pioneeringly utilized, achieving targeted regulation of carbonyl groups with increase from 27.9 to 43.3 at%, which efficiently change the electronic structure of the carbon framework and realize the dual‐ion adsorption of Na+ and ClO4−, according well with the theoretical calculations. As expected, the obtained carbon cathode delivers a specific capacity of 145 mAh g−1, higher than that of the parent carbon material (95 mAh g−1). Impressively, the ex situ X‐ray Photoelectron Spectroscopy and in situ Raman reveals that carbonyl can act as dual‐ion active sites for Na+ and ClO4− through pseudocapacitive behavior under different voltage states. Notably, the assembled SIC using the carbonyl‐rich carbon cathode exhibits an ultrahigh energy density of 162 Wh kg−1. This work opens a novel avenue for regulating the carbonyl content of carbon materials.

Research on the spoilage potential and metabolic patterns of specific spoilage bacteria in grouper (Epinephelus lanceolatus) during cold storage

Pseudomonas fragi and Serratia liquefaciens are key spoilage microorganisms in aerobically packed groupers during cold storage. Spoilage bacteria were inoculated into fillets to investigate their spoilage potential. The results showed that P. fragi had stronger degradation activity, and the P. fragi inoculated group had higher total volatile basic nitrogen (TVB-N) and K values, lower water holding capacity (WHC), and textural qualities. The P. fragi inoculated group had higher levels of carbonyl groups and lower levels of sulfhydryl groups, indicating higher levels of protein oxidation. The secondary and tertiary structure of myofibrillar protein (MP), scanning electron microscopy, and low-field nuclear magnetic resonance (LF-NMR) analyses showed that P. fragi degraded myofibrils more and induced water loss from the muscle. Metabolomics analyses indicated that purine metabolism and glycine, serine, and threonine metabolism were important pathways associated with P. fragi spoilage; linoleic acid metabolism and β-alanine metabolism were important pathways for S. liquefaciens spoilage.

The Use of the Carbonyl Group (C-3) of Isatin for the Construction of Pyrazoline Moiety and the Study of its Antioxidant Activity

A series of novel pyrazoline derivatives 5-13 were synthesized in three steps from isatin, with yields ranging from 40 to 72% over the multistep procedure. The first step included the condensation of isatin with p-aminoacetophenone to afford the corresponding Schiff base 1 in a 75% yield. In the second step, the enolate form of Schiff base 1 was reacted with different aromatic aldehydes (benzaldehyde, p-nitrobenzaldehyde, and p-chlorobenzaldehyde) to give the title chalcone derivatives 2-4 in 60-72 yields. In the third step, pyrazoline derivatives 5-13 were synthesized via cycloaddition reactions between compounds 2-4 and hydrazine hydrate, phenyl hydrazine, or p-nitrophenyl hydrazine. The cycloaddition produced the target pyrazoline compounds in 40-72% isolated yields. All prepared compounds were characterized by FT-IR and 1H NMR spectroscopy. Some of the prepared compounds were tested for antioxidant properties.

Ab Initio Molecular Dynamics Studies of Stacked Adenine–Thymine and Guanine–Cytosine Nucleic Acid Base Pairs in Aqueous Solution

Ab initio MD studies have been performed on stacked adenine–thymine (A–T) and guanine–cytosine (G–C) nucleobase pairs solvated in water using Born–Oppenheimer molecular dynamics. These two systems have been analyzed using RDF, SDF, angle–distance CDF (combined distribution functions), plane projection analysis, hydrogen bond analysis, and non–covalent interaction (NCI) plots. The stacking property studies have shown that the molecular orientation of the A–T pair is completely opposite to that of the G–C pair though the center of mass distance between the two molecules is similar. The G–C pair shows significantly more stability in water than the A–T system does. RDF analyses show that the –NH– group and carbonyl groups show predominant interaction with water molecules. Water molecules are found to be most in numbers around the cytosine molecule and least around the adenine molecule. Hydrogen bonding studies show that the guanine molecule forms the highest number of hydrogen bonds with water molecules. On the other hand, the hydrogen atom attached to the –NH– group of adenine molecule shows the longest mean H–bond lifetime with water oxygen atoms. NCI interactions calculated through the ab initio method help us to visualize the [Formula: see text]-electron stacking and H–bonding between aromatic nucleobases and water molecules. A great shift in bond polarity and interaction intensity in different functional groups is observed for the nucleobases going from individually solvated molecules to paired states.

Acid catalyzed condensation of primary/secondary amines with 2-oxo-2-aryl-N-arylethanethioamides: a highly regioselective synthesis of α-oxoamidines

In this letter, we present the synthesis of α-oxoamidines by the condensation of primary/secondary amines with N-aryl-α-oxothioamides catalyzed by benzoic acid in toluene at 80 °C. The required substrates N-aryl-α-oxothioamides were synthesized by the sodium hydride induced condensation of aromatic amines with α-oxodithioesters. The amines highly regioselectively reacted with thiocarbonyl group over carbonyl group to afford α-oxoamidines. The present method overcomes the limitations of the earlier reported methods.

Electrophilic aromatic substitution of electron-rich arenes with N-fluorobenzenesulfonimide (NFSI) as an electrophile.

An efficient amidation of electron-rich arenes using NFSI as a nitrogen source has been successfully disclosed. This amidation process can be easily conducted at elevated temperatures, without the need for catalysts or additives. A wide range of arenes substituted with hydroxy, alkoxy, or carbonyl groups were found to be compatible, yielding the desired amination products. Computational study shows that the amidation proceeds via an electrophilic aromatic substitution pathway, comprising a three-step process that includes substitution, addition, and elimination, which differs slightly from the classical mechanism.

Multifunctionalization of Alkenyl Alcohols via a Sequential Relay Process.

Aryl-substituted aliphatic amines are widely recognized as immensely valuable molecules. Consequently, the development of practical strategies for the construction of these molecules becomes increasingly urgent and critical. Here, we have successfully achieved multifunctionalization reactions of alkenyl alcohols in a sequential relay process, which enables transformation patterns of arylamination, deuterated arylamination, and methylenated arylamination to the easy access of multifarious arylalkylamines. Notably, a novel functionalization mode for carbonyl groups has been developed to facilitate the processes of deuterium incorporation and methylene introduction, thereby providing new means for the diverse transformations of carbonyl groups. This methodology displays a wide tolerance toward functional groups, while also exhibiting good applicability across various skeletal structures of alkenols and amines.

Selective Hydroboration of C−C Single Bonds without Transition‐Metal Catalysis

AbstractSelective hydroboration of C−C single bonds presents a fundamental challenge in the chemical industry. Previously, only catalytic systems utilizing precious metals Ir and Rh, in conjunction with N‐ and P‐ ligands, could achieve this, ensuring bond cleavage and selectivity. In sharp contrast, we discovered an unprecedented and general transition‐metal‐free system for the hydroboration of C−C single bonds. This methodology is transition‐metal and ligand‐free and surpasses the transition‐metal systems regarding chemo‐ and regioselectivities, substrate versatility, or yields. In addition, our system tolerates various functional groups such as Ar−X (X=halides), heterocyclic rings, ketones, esters, amides, nitro, nitriles, and C=C double bonds, which are typically susceptible to hydroboration in the presence of transition metals. As a result, a diverse range of γ‐boronated amines with varied structures and functions has been readily obtained. Experimental mechanistic studies, density functional theory (DFT), and intrinsic bond orbital (IBO) calculations unveiled a hydroborane‐promoted C−C bond cleavage and hydride‐shift reaction pathway. The carbonyl group of the amide suppresses dehydrogenation between the free N−H and hydroborane. The lone pair on the nitrogen of the amide facilitates the cleavage of C−C bonds in cyclopropanes.

Selective C6‐Nitration of Benzothiazolones with Iron Nitrate

AbstractWe report here a selective C6‐nitration of benzothiazolones in the presence of iron nitrate as nitro source. A series of novel 6‐nitrobenzothiazolin‐2‐one derivatives were prepared with moderate to excellent yields at room temperature. The method shows good regioselectivity, broad substrate scope and excellent compatibility with functional groups. Further transformations were performed for the reduction of nitro groups, amination of carbonyl groups and alkylation of amine at the 3‐position in the product.

Hepatic GPx1 and GIT1 expression altered by ethanol exposure during third trimester-equivalent development

Background Ethanol (EtOH) exposure throughout gestation and breastfeeding leads to multiple adverse outcomes in the hepatic system. Under oxidative stress, alterations in the liver are related to the inhibition of induced nitric oxide synthase activity in sinusoidal cells as a consequence of low expression of G-protein-coupled receptor (GPCR)-kinase interacting (GIT1). Here, we hypothesized that both glutathione peroxidase 1 (GPx1) and GIT1 could be altered by EtOH exposure during the third trimester of human equivalent development. Methods We exposed rats during the third trimester equivalent [postnatal days (PD) 2-8] to moderate levels of maternal EtOH (20%). GPx1 and GIT1 expression was detected by western blotting, and the antioxidant activity of glutathione peroxidase GPx and the concentration of hepatic carbonyl groups (CG were determined by spectrophotometry. Serum biochemistry parameters such as alanine aminotransferase (ALT), glucose (gluc), cholesterol (chol), and triglycerides (TG) were also measured. Results We found that ethanol decreased both GIT1 and GPx1 selenoprotein expression, affecting GPx antioxidant activity and increasing protein oxidation. Conclusions These results demonstrate for the first time that the GPx antioxidant system altered by EtOH exposure during the third trimester of development is related to a parallel decrease in GIT1 expression [1].

Zinc oxide nanoparticles at low dose mitigate lead toxicity in pea (Pisum sativum L.) seeds during germination by modulating metabolic and cellular defense systems

Addressing lead (Pb) pollution and contamination in soil and agriculture is urgent due to its widespread and long-lasting impacts on human health, food safety, and the environment. In the current study, we assessed the potential use of Zinc oxide nanoparticles (ZnONPs) in alleviating Pb toxicity in germinating seedlings. Pea (Pisum sativum L.) seedlings were exposed to Pb (83 mg/L) over a 7-day period, without and with ZnONPs amendment. Our results showed that the application of ZnONPs at 10 mg/L restored the morphological parameters affected by Pb, 34 %, 26 % and 23 %, for the length, fresh, and dry biomass of embryonic axis, respectively. ZnONPs decreased the activities of antioxidative enzymes of catalase (87.5 %), guaiacol peroxidase (60 %), and glutathione peroxidase (25 %), but increased the activities of ascorbate peroxidase (60 %) and glutathione reductase (25 %). These changes were associated with the increase (7 %) in the thiol groups, and reductions in the malondialdehyde (23 %), hydrogen peroxide (33 %), and carbonyl group levels (78 %), in addition to the stimulation of the activities of ROS-associated enzymes, including glycolate oxidase (40 %) and NADPH oxidase (by 89 %). Consequently, cell viability was increased by 66 %, while cellular death was reduced by 10 %, with ZnONPs, relative to the Pb-stressed seedlings. These findings highlight the mechanisms surrounding the ability of nanosized ZnO to mitigate the harmful effects of Pb on the growth and physiology of plants. Further investigation is needed to understand the mitigating effects of ZnONPs on Pb on the molecular and genomic levels in seedlings and plants, and ensure the sustainability of agricultural practices and food safety. Besides, site and source-specific integrated approaches must be practiced to formulate suitable remediation strategies.

Late-stage Functionalization using a Popular Titrating Agent: Aryl-Chlorides and -Fluorides Activation by the Diphenylacetic Acid Dianion.

Aryl-chlorides and -fluorides are common building blocks, but their use in synthesis is limited by the high stability of their Ar-X bonds. The generation of aryl radicals via activation of strong Ar-X bonds is possible through the irradiation of tailor-made organic anions, which become reductants stronger than lithium metal. We report that the combination of visible light with the cheap diphenylacetic acid dianion is an even better tool, showing excellent activity across a variety of complex substrates and providing opportunities for late-stage drug modification. Ar-X bonds are chemoselectively activated in the presence of more easily reducible functions, such as Alk-Cl ones and carbonyl groups. These results pave the way to original synthetic strategies that would be otherwise considered impossible.

Preparation of low‐temperature self‐crosslinking acrylic resin and its performance research

AbstractAcrylic resin, as a common coating and adhesive, possesses excellent heat resistance, weather resistance, and is inexpensive, making it widely used in industries related to automotive, construction, electronics, fabrics, and other sectors essential to our daily life. Traditional acrylic resin not only pollutes the environment but also poses certain health risks. Therefore, we studied the synthesis of a low‐temperature self‐crosslinking acrylic emulsions were synthesized by free radical solution polymerization using methyl methacrylate (MMA), butyl acrylate (BA), acrylic acid (AA), diacetone acrylamide (DAAM), hydroxypropyl acrylate (HPA), epoxy resin (E‐51) as the monomers, vinyltriethoxysilane (A‐51) as the coupling agent, and adipic dihydrazide (ADH) as the cross‐linking agent. This water‐based acrylic resin undergoes a crosslinking reaction between the carbonyl group of DAAM and the hydrazide group of ADH, substantially improved the drying speed and adhesion compared to unmodified versions, and also improved the thermal stability. The contact angle of the film increased from 72.8° to 86.9° with the increase of the degree of cross‐linking, and the mechanical properties were improved by 60%. This study provides a suitable formulation for preparing water‐based acrylic resins with superior performance.

Binding of Glutamic Acid to Silver and Gold Nanoparticles Investigated by Surface-Enhanced Raman Spectroscopy

Glutamate is the most important excitatory neurotransmitter, which is relevant for the study of several diseases such as amyotrophic lateral sclerosis and Alzheimer. It is the form L-glutamic acid (Glu) takes at physiologically relevant pHs. The surface-enhanced Raman spectra of Glu obtained at pH values ranging from 3.3 to 12 are collected in the presence of silver and gold colloids and on solid substrates. The observed bands are compared with the positions of calculated normal modes for free neutral glutamic acid, glutamic acid monohydrate, glutamic acid bound to gold and silver atoms, and sodium glutamate. Although gold atoms prefer to bind to the NH2 group as compared to carbonyl groups, silver atoms prefer binding to hydroxyl groups more than binding to the amino group. SERS spectra of glutamic acid solutions with a pH value of 12, in which both carboxylic groups are deprotonated, indicate a complexation of the glutamic acid dianion with the sodium cation, which was introduced into the solution to adjust the pH value. Further research towards an optimal substrate is needed.

Olive pomace upcycling: Eco-friendly production of cellulose nanofibers by enzymatic hydrolysis and application in starch films.

Olive pomace (OP) waste, produced in large quantities, contains significant amounts of cellulose and fibers, making it a valuable resource for developing reinforcing ingredients in biodegradable packaging materials. This study aimed to produce nanofibers from OP using enzymatic hydrolysis with hemicellulases and cellulases, and to incorporate these nanofibers into starch films as a reinforcing agent. Cellulose nanofibers (CNFs) were prepared by alkaline pretreatment followed by enzymatic hydrolysis (with hemicellulases and cellulases) from olive pomace and applied as reinforcement in starch films in concentrations of 0.5%-5% (w/v). The nanofibers were analyzed according to composition, structural, and thermal properties. The nanofibers' suspension presented a cloudy and white color in aqueous suspension, the X-ray diffraction (XRD) analysis showed the increase of crystallinity, and the fibers' range was no wider than 100nm (according to Scherer equation). The composition analysis showed the decrease of carbonyl groups of hemicellulose and lignin. The starch films presented a homogenous surface. The solubility from these biodegradable films significantly reduced after the incorporation of CNF, and the nanomaterial's presence improved the degradation temperature (from 310°C to 322°C) and the mechanical resistance because the tension of rupture increased from 3.79 to 6.21MPa. PRACTICAL APPLICATION: The utilization of waste from the olive pomace for cellulose nanofiber production holds promise, given the nanofibers' ability to readily integrate into various materials, including starches used in biodegradable film production. Within these matrices, nanofibers act as structure reinforcers and significantly reduce the solubility of films. Although biodegradable films ensure the shelf life, safety, and quality of food, their properties currently do not match those of traditional petroleum-based materials at an industrial scale, indicating a need for further enhancement.

Insights into the influence of anions on the syngas production behavior of bio-wastes during molten salt thermal treatment

Thermal treatment of bio-wastes in molten nitrate at low temperatures has emerged as an efficient approach for producing syngas. Molten salt facilitates the thermal conversion of bio-wastes due to its superior heat transfer and catalytic properties. To enhance the depolymerisation of macromolecules in bio-wastes for the production of high-quality syngas, molten NaNO3-NaNO2 with varying anion ratios was employed in this study, and the effects of these anions on bio-wastes with diverse properties were thoroughly investigated. The results indicated that NO3− tended to be significantly involved in the cleavage of carbonyl groups and C–C/CC bonds, which dominated the high CO2 production. NO2− tended to be significantly involved in the cleavage of ether and C–C/CC bonds, which dominated the high CO production. The elevated NO2− ratio in molten salt significantly facilitated the depolymerisation of bio-wastes, increasing the yield of combustible gases (CO, CH4, H2) while decreasing CO2 yield in the syngas. This resulted in a notable enhancement of the lower heating value (LHV) of syngas, reaching up to 11.55 MJ/Nm3. This behavior also led to the formation of substantial quantities of nitro-phenols and amines containing nitro/nitroso groups in the tar. The nitrosation reaction of NO2− with bio-wastes was the primary factor in this process and took precedence over the nitrification of NO3−. This study elucidated the reaction pathways of NO3−/NO2− with bio-wastes and their contributions to the production of high-quality syngas at low temperature.