Carbonyl Compounds Research Articles

Modular Synthesis of Tetrasubstituted Vinyl Sulfides via One-Pot Sequential Carbene Transfer Reaction from Thiols with α-Diazo Carbonyl Compounds.

We present a one-pot reaction that offers an efficient approach to synthesizing tetrasubstituted vinyl sulfides with high stereoselectivity. This method involves the sequential Wolff rearrangement, ylide formation, and [1,4]-aryl transfer by utilizing aryl and alkyl thiols and α-diazo carbonyl compounds as substrates. Notably, this reaction features commercially available materials, straightforward operation, atom economy, and broad substrate scope. Moreover, the primary photophysical properties (aggregation-induced emission effect) of the products were also investigated, which might be useful in functional materials via structural modification.

MicroRNA-Dependent Mechanisms Underlying the Function of a β-Amino Carbonyl Compound in Glioblastoma Cells

MicroRNA-Dependent Mechanisms Underlying the Function of a β-Amino Carbonyl Compound in Glioblastoma Cells

Carbonylation Reactions of a Metallapentalyne: Synthesis of Its Ester and Amide Derivatives

Comprehensive SummaryCarbonylation reactions are a valuable synthetic method to construct carbonyl compounds and carbonylation reactions of aryl halides stand out as a highly significant tool for generating carbonyl substituted arenes. However, the important reactions have never been realized in aromatic metallacycles. Herein, we present the first carbonylation reactions of metallaaromatics, specifically alkoxycarbonylation and aminocarbonylation reactions of an osmapentalyne. During the carbonylation process, the electronic and steric properties of nucleophiles are regarded as critical factors. The alcohols with bulky substituents (isopropanol) require more reaction time and tert‐butyl alcohol is inert in the reaction. Comparatively, amines, being stronger nucleophiles, exhibit divergent behaviors. Bulky amines undergo aminocarbonylation, whereas small amines prefer direct nucleophilic additions. Control experiments revealed that the intermediate derived from coupling of metal carbyne with CO plays a significant role in the carbonylation reaction. According to these observations, a divergent pathway for the reaction is proposed. Furthermore, the photophysical properties of these carbonyl‐functionalized osmapentalene complexes are studied, and the maximum absorption peak of compound with a carboxylic group exhibits a significant red‐shift due to the smaller HOMO‐LUMO gap. These findings contribute to expanding the reactivity of metallaaromatics and offer new opportunities for the synthesis of carbonyl‐functionalized metallacycles.

Orange Juice: A Remarkable Green Catalyst for the Michael Addition Reaction of Indoles

Michael addition reaction is widely accepted as the most important reaction for making carbon-carbon bonds in the synthesis of organic compounds. In this reaction, an enone is attacked by a nucleophile in a conjugated manner across a carbon-carbon double bond. The present work reported the Michael reaction of indole with α,β-unsaturated ketones via alkylation to yield 3-(3-oxoalkyl) indole or β-indolyl ketones. Naturally available orange juice has been demonstrated to be an efficient green catalyst for the Michael addition reaction of indoles with various cyclic and acyclic unsaturated ketones. The products were characterised by 1H NMR spectroscopy and compared with literature. This one-step, simple process has afforded the 3-indolyl carbonyl compounds in short reaction times and excellent yields at room temperature. The present method developed an inexpensive synthetic process to prepare substituted indoles in a simple and eco-friendly way.

Antimony Redox Catalysis: Hydroboration of Disulfides through Unique Sb(I)/Sb(III) Redox Cycling.

The stibinidene ArSbI (Ar = [2,6-(tBuN═CH)2-C6H3], 1) reacts with S2Tol2 (Tol = p-tolyl) to form ArSbIII(STol)2 (2), which upon treatment with pinacolborane, regenerates 1. These processes unveil an unprecedented antimony redox catalysis involving Sb(I)/Sb(III) cycling for the hydroboration of organic disulfides. Elementary reaction studies and density functional theory calculations support that the catalysis mimics transition metal processes, proceeding through oxidative addition, ligand metathesis, and reductive elimination. The thiophenols and sulfidoborates generated from the hydroboration of disulfides react in situ with α,β-unsaturated carbonyl compounds with the assistance of 1 as a base catalyst. These tandem reactions establish a one-pot synthetic method for β-sulfido carbonyl compounds, in which a stibinidene functions as a redox catalyst and a base catalyst successively, illustrating the versatility and efficiency of antimony catalysis in organic synthesis.

Antimony Redox Catalysis: Hydroboration of Disulfides through Unique Sb(I)/Sb(III) Redox Cycling.

The stibinidene ArSbI (Ar = [2,6-(tBuN═CH)2-C6H3], 1) reacts with S2Tol2 (Tol = p-tolyl) to form ArSbIII(STol)2 (2), which upon treatment with pinacolborane, regenerates 1. These processes unveil an unprecedented antimony redox catalysis involving Sb(I)/Sb(III) cycling for the hydroboration of organic disulfides. Elementary reaction studies and density functional theory calculations support that the catalysis mimics transition metal processes, proceeding through oxidative addition, ligand metathesis, and reductive elimination. The thiophenols and sulfidoborates generated from the hydroboration of disulfides react in situ with α,β-unsaturated carbonyl compounds with the assistance of 1 as a base catalyst. These tandem reactions establish a one-pot synthetic method for β-sulfido carbonyl compounds, in which a stibinidene functions as a redox catalyst and a base catalyst successively, illustrating the versatility and efficiency of antimony catalysis in organic synthesis.

Intermolecular α-Functionalization of Benzylamides with N-Nucleophiles via Oxidative Umpolung: Synthesis of Tetrasubstituted 3,3'-Oxindoles.

A hypervalent iodine-mediated intermolecular α-umpolung reaction between α-aryl- or alkyl-substituted amides and benzotriazoles or purine derivatives as N-centered nucleophiles has been established. The reaction involves sequential intra/intermolecular oxidative C-N couplings in a controlled manner, affording tetrasubstituted 3,3'-oxindoles in moderate to good yields. This approach efficiently addresses the challenges in constructing tetrasubstituted carbon centers via α-umpolung functionalizations of carbonyl compounds and serves as a new strategy for synthesizing biologically important 3,3'-disubstituted oxindoles.

Intermolecular α-Functionalization of Benzylamides with N-Nucleophiles via Oxidative Umpolung: Synthesis of Tetrasubstituted 3,3'-Oxindoles.

A hypervalent iodine-mediated intermolecular α-umpolung reaction between α-aryl- or alkyl-substituted amides and benzotriazoles or purine derivatives as N-centered nucleophiles has been established. The reaction involves sequential intra/intermolecular oxidative C-N couplings in a controlled manner, affording tetrasubstituted 3,3'-oxindoles in moderate to good yields. This approach efficiently addresses the challenges in constructing tetrasubstituted carbon centers via α-umpolung functionalizations of carbonyl compounds and serves as a new strategy for synthesizing biologically important 3,3'-disubstituted oxindoles.

Energetics of the OH radical H-abstraction reactions from simple aldehydes and their geminal diol forms.

Carbonyl compounds, especially aldehydes, emitted to the atmosphere, may suffer hydration in aerosols or water droplets in clouds. At the same time, they can react with hydroxyl radicals which may add or abstract hydrogen atoms from these species. The interplay between hydration and hydrogen abstraction is studied using density functional and quantum composite theoretical methods, both in the gas phase and in simulated bulk water. The H-abstraction from the aldehydic and geminal diol forms of formaldehyde, acetaldehyde, glycolaldehyde, glyoxal, methylglyoxal, and acrolein is studied to determine whether the substituent has any noticeable effect in the preference for the abstraction of one form or another. It is found that abstraction of the H-atom adjacent to the carbonyl group gives a more stable radical than same abstraction from the geminal diol in the case of formaldehyde, acetaldehyde, and glycolaldehyde. The presence of a delocalizing group in the Cα (a carbonyl group in glyoxal and methylglyoxal, and a vinyl group in acrolein), reverts this trend, and now the abstraction of the H-atom from the geminal diol gives more stable radicals. A further study was conducted abstracting hydrogen atoms from the other different positions in the species considered, both in the aldehydic and geminal diol forms. Only in the case of glycolaldehyde, the radical formed by H-abstraction from the -CH2OH group is more stable than any of the other radical species. Abstraction of the hydrogen atom in one of the hydroxyl groups in the geminal diol is equivalent to the addition of the •OH radical to the aldehyde. It leads, in some cases, to decomposition into a smaller radical and a neutral molecule. In these cases, some interesting theoretical differences are observed between the results in gas phase and (simulated) bulk solvent, as well as with respect to the method of calculation chosen. DFT (M06-2X, B2PLYP, PW6B95), CCSD(T), and composite (CBS-QB3, jun-ChS, SCVECV-f12) methods using Dunning basis sets and extrapolation to the CBS limit were used to study the energetics of closed shell aldehydes in their keto and geminal-diol forms, as well as the radical derived from them by hydrogen abstraction. Both gas phase and simulated bulk solvent calculations were performed, in the last case using the Polarizable Continuum Model.

Catalytic Stability of S-1-(4-Hydroxyphenyl)-Ethanol Dehydrogenase from Aromatoleum aromaticum.

Derived from the denitrifying bacterium Aromatoleum aromaticum EbN1 (Azoarcus sp.), the enzyme S-1-(4-hydroxyphenyl)-ethanol dehydrogenase (S-HPED) belongs to the short-chain dehydrogenase/reductase family. Using research techniques like UV-Vis spectroscopy, dynamic light scattering, thermal-shift assay and HPLC, we investigated the catalytic and structural stability of S-HPED over a wide temperature range and within the pH range of 5.5 to 9.0 under storage and reaction conditions. The relationship between aggregation and inactivation of the enzyme in various pH environments was also examined and interpreted. At pH 9.0, where the enzyme exhibited no aggregation, we characterized thermally induced enzyme inactivation. Through isothermal and multitemperature analysis of inactivation data, we identified and confirmed the first-order inactivation mechanism under these pH conditions and determined the kinetic parameters of the inactivation process. Additionally, we report the positive impact of glucose as an enzyme stabilizer, which slows down the dynamics of S-HPED inactivation over a wide range of pH and temperature and limits enzyme aggregation. Besides characterizing the stability of S-HPED, the enzyme's catalytic activity and high stereospecificity for 10 prochiral carbonyl compounds were positively verified, thus expanding the spectrum of substrates reduced by S-HPED. Our research contributes to advancing knowledge about the biocatalytic potential of this catalyst.

Catalytic Stability of S-1-(4-Hydroxyphenyl)-Ethanol Dehydrogenase from Aromatoleum aromaticum

Derived from the denitrifying bacterium Aromatoleum aromaticum EbN1 (Azoarcus sp.), the enzyme S-1-(4-hydroxyphenyl)-ethanol dehydrogenase (S-HPED) belongs to the short-chain dehydrogenase/reductase family. Using research techniques like UV-Vis spectroscopy, dynamic light scattering, thermal-shift assay and HPLC, we investigated the catalytic and structural stability of S-HPED over a wide temperature range and within the pH range of 5.5 to 9.0 under storage and reaction conditions. The relationship between aggregation and inactivation of the enzyme in various pH environments was also examined and interpreted. At pH 9.0, where the enzyme exhibited no aggregation, we characterized thermally induced enzyme inactivation. Through isothermal and multitemperature analysis of inactivation data, we identified and confirmed the first-order inactivation mechanism under these pH conditions and determined the kinetic parameters of the inactivation process. Additionally, we report the positive impact of glucose as an enzyme stabilizer, which slows down the dynamics of S-HPED inactivation over a wide range of pH and temperature and limits enzyme aggregation. Besides characterizing the stability of S-HPED, the enzyme’s catalytic activity and high stereospecificity for 10 prochiral carbonyl compounds were positively verified, thus expanding the spectrum of substrates reduced by S-HPED. Our research contributes to advancing knowledge about the biocatalytic potential of this catalyst.

Conjugated Carbonyl Compound‐Enhanced Hydrogels for Tactile Recognition

AbstractHydrogels that possess both self‐healing capabilities in tissue engineering and mechanical properties play a pivotal role in advancing flexible sensing and wearable bioelectronic devices technologies. The primary challenge in practical applications revolves around the delicate equilibrium between mechanical properties and self‐regeneration capabilities. Herein, the utilization of conjugated carbonyl compound PI‐COF (Polyimide‐Covalent organic framework) is proposed as reinforcing phases to interact with iron ions, thereby preparing PAA‐based double network hydrogel with high cross‐linking density. Through comprehensive component analysis, it has been determined that the existence of metal coordination bonds, hydrogen bonds along with π–π conjugate system imparts (PAA‐2DC)‐Fe3+/PEDOT: PSS hydrogel excellent self‐healing performance (3rd, 196.2%), elongation (1312%) and tensile strength (71 kPa). Additionally, the hydrogel exhibits remarkable conductivity (σ = 0.5 S m−1), strain sensing sensitivity (GF = 9.3), self‐adhesive properties and demonstrating its ability to differentiate between materials of various sizes and possesses antibacterial properties. These exceptional attributes highlight the potential of the hydrogel in tissue engineering and flexible sensing, simultaneously providing novel research ideas and theoretical basis.

Application of Cations, Acids, and Antioxidants on Mitigating Acrylamide Formation in Food with a Special Focus on Potato and Cereal Based Foods - A Review

Acrylamide is a toxic substance that formsin food during high-temperature processing methods such as deep-frying, baking, and roasting, through the Maillard reaction or the acrolein pathway. Since acrylamide has been identified for its carcinogenicity, genotoxicity, and neurotoxicity, global food authorities have established benchmark levels for different food categories. Consequently, researchers have proposed various mitigation strategies, focusing on agronomical, chemical, physical, and microbial approaches. However, most of these approaches are associated with high cost, technology, extended time, and poor sensory and nutritional quality. In this context, application of various additives such as metal cations, organic and inorganic acids, and antioxidants in optimum amounts have been effective in reducing acrylamide formation. Additives contribute to reducing acrylamide either by interacting with its precursors and/or intermediate products or by breaking down acrylamide into other non-toxic substances. Since cations can form thermostable asparagine/matrix intermediates through chelation reaction between asparagine and metal cations, asparagine will be unavailable to react with carbonyl compounds to form the Schiff base. Lower pH conditions inhibit the acrylamide formation by blocking the protonation of the α-amino group of asparagine and reducing any possibility for nucleophilic addition reactions with carbonyl groups. Toxicity associated with Maillard products can be reduced by using antioxidants in the frying oil or the food. Polyphenols are capable of reducing the acrylamide formation by directly trapping acrylamide at elevated temperature. It is essential to identify the most appropriate additive, its concentration and the optimum process conditions when applying additives to get an optimal acrylamide inhibition. This review article highlights the effect of various additive applications, their effectiveness and possible future advances in food to control acrylamide formation within the accepted level.Keywords: Acrylamide, Antioxidant, Carcinogenicity, Deep-frying, Maillard reaction

A tutorial on solid-phase analytical derivatization in sample preparation applications

Solid-phase analytical derivatization is a versatile sample preparation technique that enhances analysis accuracy, efficiency, reproducibility, and sensitivity. The technique combines the advantages of analytical derivatization and solid-phase extraction, providing a versatile approach for analysing analytes with various functional groups in complex matrices. Analytical derivatization is a technique used for functional group analysis that involves modifying the structure of an analyte to enhance sensitivity and specificity. Solid-phase analytical derivatization is a one-pot procedure that combines analytical derivatization and extraction. In the presence of acids, it can derivatize phenols, carboxylic acids, and other analytes. Furthermore, solid-phase analytical derivatization increases the reaction rate of carbonyl compounds, making it easier to extract aldehydes and ketones rapidly. This technique utilises electrophoresis, chromophores, fluorophores, and functional groups for detection and extraction. It initially began as a batch procedure but has now developed into an automated, microextraction, and derivatization method. Solid-phase analytical derivatization is highly efficient due to the significant excess of the derivatizing reagent relative to the analyte, along with the pre-impregnation of derivatizing reagents, which can speed up the process compared to traditional solution-based derivatization. This tutorial aims to provide detailed insights into the practical aspects of implementing solid-phase analytical derivatization in analytical method development and discuss the prospects and future trends.

Functionalized olive wood shell stone as a new revalorized agri-food waste active in organocatalysis

Olive wood shell stone has been used as an effective matrix for silanization and further anchoring of an organic probe such as 3-(5-chloro-anthraquinonylamino)propanoic acid (1). Covalent fixation of the anthraquinoid molecule was achieved by a “grafting to” silanization process with 3-aminopropyltrimethoxysilane (APTMS) followed by an amidation procedure. Ligand 1 was routinely characterized by multinuclear magnetic resonance (1H, 13C and 15N) and X-ray diffraction crystallography, while the new agri-food revalorized organocatalyst material was characterized by a number of analytical techniques such as granulometry, elemental analysis, thermogravimetry, differential scanning calorimetry, X-ray photoelectron spectroscopy, FTIR (ATR and DRIFT), moisture content, Karl-Fisher, ζ-potential and optical and fluorescence microscopy. The new revalorized material was assayed in the heterogeneous organocatalytic cyanosilylation of carbonyls compounds under very mild conditions with excellent yields and high recyclability under both presence and absence of solvent. Kinetic studies were also performed in order to understand the water uptake implications of this new organocatalyst.

Vinyltriarylbismuthonium Salts: Powerful Vehicles for α-Vinylation of Carbonyl Compounds.

α-Vinyl-carbonyl compounds are a class of orthogonally functionalized molecules, wherein the intrinsic C═O and C═C bonds can be used to unlock distinctly different reactivities. In this report, we present a simple method for the direct α-vinylation of carbonyl compounds utilizing vinyltriarylbismuthonium ("Vinyl-Bis") salts, which are stable and readily preparable on a decagram scale. This transformation is accomplished efficiently through the reaction of an in situ generated Li-enolate intermediate with a Vinyl-Bis reagent, leading to the formation of α-vinylated carbonyl compounds in good to excellent yields and with a remarkably broad substrate scope. Critically, this vinylation method is effective for enolates generated via numerous methods, enabling the sequencing of reactions that generate enolates with the vinylation step and the ready synthesis of diversely functionalized compounds, thereby underscoring the versatility and practicality of this method. Analogous reactions of discrete Li-enolates with other vinyl units and with aryl groups are also demonstrated.

Recent Progress in the Conversion of Methylfuran into Value-Added Chemicals and Fuels.

2-methylfuran is a significant organic chemical raw material which can be produced by hydrolysis, dehydration, and selective hydrogenation of biomass hemicellulose. 2-methylfuran can be converted into value-added chemicals and liquid fuels. This article reviews the latest progress in the synthesis of liquid fuel precursors through hydroxyalkylation/alkylation reactions of 2-methylfuran and biomass-derived carbonyl compounds in recent years. 2-methylfuran reacts with olefins through Diels-Alder reactions to produce chemicals, and 2-methylfuran reacts with anhydrides (or carboxylic acids) to produce acylated products. In the future application of 2-methylfuran, developing high value-added chemicals and high-density liquid fuels are two good research directions.

Synthesis of Multisubstituted 2,3-Allenamides via Palladium-Catalyzed Carbonylation of Propargylic Esters.

2,3-Allenamides are an important class of unsaturated group-substituted carbonyl compounds. A palladium-catalyzed aminocarbonylation of propargyl acetates with amines for the synthesized tri-/tetrasubstituted 2,3-allenamides has been developed. A broad range of tri-/tetrasubstituted 2,3-allenamides have been prepared from propargyl acetates in good to excellent yields. The reaction featured mild reaction conditions and good functional group tolerance. The applicability of this methodology was further highlighted by the late-stage modification of several natural products and pharmaceuticals.

Multielectron Reduction of Esters by a Diazabenzacenaphthenium Photoredox Catalyst.

A novel diazabenzacenaphthenium photocatalyst, N-BAP, with high photoredox abilities and visible-light absorption was designed and prepared in one step. Under visible-light irradiation, N-BAP promoted the four-electron reduction of esters in the presence of ammonium oxalate as a "traceless reductant" to generate carbinol anion intermediates that underwent protonation with water to give the corresponding alcohols. The resulting carbinol anions also exhibited nucleophilic reactivity under the photocatalytic conditions to undergo a 1,2-addition to a second carbonyl compound, affording unsymmetric 1,2-diols.

A refined picture of the native amine dehydrogenase family revealed by extensive biodiversity screening

Native amine dehydrogenases offer sustainable access to chiral amines, so the search for scaffolds capable of converting more diverse carbonyl compounds is required to reach the full potential of this alternative to conventional synthetic reductive aminations. Here we report a multidisciplinary strategy combining bioinformatics, chemoinformatics and biocatalysis to extensively screen billions of sequences in silico and to efficiently find native amine dehydrogenases features using computational approaches. In this way, we achieve a comprehensive overview of the initial native amine dehydrogenase family, extending it from 2,011 to 17,959 sequences, and identify native amine dehydrogenases with non-reported substrate spectra, including hindered carbonyls and ethyl ketones, and accepting methylamine and cyclopropylamine as amine donor. We also present preliminary model-based structural information to inform the design of potential (R)-selective amine dehydrogenases, as native amine dehydrogenases are mostly (S)-selective. This integrated strategy paves the way for expanding the resource of other enzyme families and in highlighting enzymes with original features.