Carbonyl Compounds Research Articles

Characterization of modified low‐density polyethylene by cold atmospheric pressure plasma jet treatment in the melt state

AbstractCold plasma treatment in the melt state is a novel area of research focused on producing modified polymers, hence more research on the underlying plasma‐polymer interactions in this context is needed. In this study, low‐density polyethylene (LDPE) was treated with a cold atmospheric pressure plasma jet (CAPPJ) during melt processing in a polymer batch mixer. Electron spin resonance (ESR) results proved that plasma treatment effectively generates free radicals in the material, increasing the room temperature spin concentration by an order of magnitude to 2 × 1015 spins g−1. The generated radicals react mainly by cross‐linking, forming a gel phase of up to 31%, and consequently increasing the polymer's melt viscosity. Furthermore, oxidation was established as solely a thermal effect limited by radical availability at the interface exposed to the atmosphere, whereas plasma exposure did not lead to further oxidation. Interestingly, plasma appears to interact with the thermally created ketone groups, possibly forming unsaturated carbonyl compounds.

Dual Photoredox and Titanium Catalyzed Regioselective Allenylation of Aldehydes via Reductive Radical‐Polar Crossover

Comprehensive SummaryThe direct reductive coupling of carbonyl compounds with propargyl halides is a powerful and reliable tool in the synthesis of α‐allenols. However, stoichiometric metal reductants, harsh reaction conditions and a variety of additional additives are required in the traditional strategies. Additionally, the reactivity and regioselectivity control remains an elusive challenge. Herein, we developed the Ti‐catalyzed regioselective reductive coupling of readily available aldehydes and racemic propargyl bromides to rapidly access a wide range of α‐allenols. This method proceed efficiently in a reductive radical‐polar crossover manner featuring mild conditions, excellent regioselectivity control, broad substrate scope, and eco‐friendliness. Preliminary mechanistic studies support the radical‐involved catalytic cycle. And the DFT calculations demonstrate that the regioselectivity is determined by the Zimmerman‐Traxler‐type transition states.

Designing plausible catalysts for synthesis of zingerone from vanillin and acetone via aldol condensation reaction on O-terminated M3C2-MXenes

Herein, high-performance O-terminated M3C2 MXene catalysts were screened for the synthesis of zingerone using vanillin and acetone. The electrochemical and electronic properties of O-terminated ordered MXenes in the form of M3C2O2(H) [M = Ti, V, and Cr (3d); Zr, Nb, and Mo (4d); and Hf, Ta, and W (5d)] were investigated using first principle density functional theory (DFT) calculations. These calculations revealed 37 stable candidates based on their negative binding energy values of ΔG*H and three O-terminated M3C2 MXene candidates with superior zingerone synthesis activity than pure precious metal (platinum), a UL > −0.4 V can guarantee high activity and low energy consumption during zingerone synthesis. Ti3C2O (FCC)), Hf3C2O2 (HCPFCC), and Nb3C2O2 (HCPHCP) exhibited higher catalytic activity than other candidates, and their performances were competitive for zingerone synthesis, with low limiting potentials of −0.37, −0.27, and −0.35 V, respectively. Zingerone synthesis via the protolysis reaction between vanillin and acetone includes two paths, i.e., induced protolysis and direct protolysis via the aldol condensation reaction. Multiple descriptors were used to evaluate and screen promising candidates for the synthesis of zingerone. For example, ΔG(*vanillin*acetone), and Bader charge, and d-band center analyses revealed the origin of zingerone synthesis activity based on binding energy and electronic structure. Importantly, binding energy and electronic structure have a strong intrinsic linear scaling relationship that can be used to screen for the optimal catalyst by controlling the scaling relationship between the intermediate binding energy and electronic properties. Indicating a scaling relationship and volcano plot were established based on ΔG(*vanillin+*acetone) and ΔG[*zingiberone] depending on Limiting potential (UL). Finally, we proposed a method for directly inducing protolysis during the aldol condensation reaction, which may be widely applicable to different biomass-derived carbonyl compounds, yielding chemicals and medicinal compounds through biomass valorization.

Facile synthesis of azines by carboxylic acid esters as catalyst and facilitation of intersystem crossing (ISC) in azines by azine chromophore

Development of new organic synthetic methods fascinating the researchers which facilitating the increasing demands of the modern society, environmental friendly with high efficiency and low cost. The introduction of chromophores in an organic molecules facilitating intersystem crossing (ISC) to harvest both singlet and triplet excitons is also currently demanding field. We report a facile synthesis of symmetrical azines from carbonyl compounds and hydrazine hydrate with carboxylic acid esters as catalyst in methanol. This reaction presents a condensation of primary amino groups in hydrazine hydrate and carbonyl compounds took place simultaneously in a very short refluxing time. The prepared azines 1–10 were structurally analysed by various analytical techniques such as LC-MS1, H NMR13, C NMR, UV-Vis, FTIR and single crystal X-ray diffraction. Photoluminescence properties of prepared azines were recorded in CCl4 at 1 × 10−3 M and excitation range from 329 to 362 nm. The photoluminescence analysis results revealed that compounds 1–10 (except 8) were showed delayed fluorescence and 8 was showed fluorescence property. The photophysical properties of compounds 1–10 such as electron density and band gap energies was calculated by density function theory. This results revealed that the intra-molecular charge transfer occurs within the azines. The azine function in the azines enabling intersystem crossing hence, it is showing phosphorescence.

Preservation with Different Smoking Techniques to Extend the Shelf Life of “Urutan” Chicken

“Urutan” chicken is one of the processed meat products processed through the manufacture of meat dough, fat and complete Balinese spices ("Basa Genep"). Extending the shelf life of “urutan” chicken can be done by smoking process either by cold smoking method or hot smoking. Smoke can preserve food ingredients due to the presence of acid, phenolic and carbonyl compounds. The method used in this study is Randomized Block Design (RBD) with a factorial pattern consisting of 2 factors, namely Factor I is Hot Smoking Technique consisting of 3 levels and Factor II is Smoking Time consisting of 4 levels so that 12 treatment combinations are obtained and 2 repetitions are carried out so that 24 experimental units are obtained. The parameters observed include phenol content, water content, ash content, fat content, protein content, Esherichia coli and Salmonella sp. Statistical analysis shows that smoking time has a significant effect (sig <0.05) on the phenol content of “urutan” chicken, but does not have a significant effect (sig> 0.05) on the fat and protein content of “urutan” chicken. The fat content of “urutan” chickens in the smoking duration treatment at a temperature of 100 ° C ranged from 9.798 - 11.870%. The lowest fat content was obtained in 2 hours of smoking, which was 9.798% which was not significantly different from other treatments. The protein content of “urutan” chickens in the smoking treatments of 0.5, 1, 1.5 and 2 hours ranged from 11.788 -12.197%. The smoking duration did not have a significant effect on the protein content of “urutan” chickens, which was probably because the smoking duration of 0.5 -2 hours had not denatured the protein sequence. The phenol content of “urutan” chickens in the smoking treatments of 0.5, 1, 1.5 and 2 hours ranged from 0.206 - 0.312%. The highest phenol content was obtained in 2 hours of smoking at a smoking temperature of 100 ° C, which was 0.312%. The results showed that the longer the smoking, the higher the phenol content of “urutan” chickens. The lowest pH value was obtained in the 100 °C 2-hour smoking treatment of 5.16, which was significantly different from other treatments. The highest water content was obtained in the 100 °C 2-hour temperature treatment of 63.19%, which was significantly different from other treatments

Dearomative Carbonylations of Arenes via Bifunctional Coordination to Cr(CO)3

Carbonylation reactions serve as powerful tools to construct useful carbonyl compounds with high efficiency and atom economy. Compared with the well-developed carbonylation chemistry for alkenes, the dearomative carbonylation of arenes is largely underexplored, possibly owing to the severe challenge in overcoming resonance stabilization of arene π-systems. Bifunctional coordination to tricarbonylchromium not only offers a reliable strategy to activate inert benzene π-bonds towards dearomatizations but also provides the CO source for the carbonylation process. Herein, we highlight the recent progress in dearomative carbonylations of chromium-bound arenes through either conventional nucleophile-electrophile addition mode or newly-developed umpolung-enabled nucleophile-nucleophile addition mode under mild CO-gas-free conditions. Given the great abundance and diversity of arene substrates, we hope this review will attract more attention to this new direction of carbonylation chemistry.

Enantioselective Electrocatalysis for the Cross-Dehydrogenative Heteroarylation of Indoles, Pyrroles, and Furans.

Oxidative cross-dehydrogenative C-H/C-H functionalizations represent an exemplary approach for synthesizing carbonyl compounds via α-heteroarylation. Here we present the development of a direct anodic oxidative coupling process between 2-acylimidazoles and divergent heterocyclic systems including indole, pyrrole, and furan, facilitated by ferrocene-assisted asymmetric nickel electrocatalysis with high levels of enantioselectivity. Mechanistic investigations indicate that the reaction initially involves the formation of a chiral Ni-bound α-carbonyl radical, which is then captured by the heteroarene radical cation via intermolecular stereoselective radical/radical cation coupling. The mild, scalable, and robust reaction conditions allow for a broad substrate scope and excellent functional group tolerance, enabling access to a wide range of chiral hetero-compounds. The consequential α-heteroaromatic carbonyl products can potentially be transformed into a plethora of synthetically valuable frameworks, as exemplified by their application in the asymmetric total synthesis of (-)-COX-2 inhibitor, (+)-acremoauxin A, and (+)-pemedolac.

Silane‐Mediated Alkylation of Arenes via Reductive Friedel‐Crafts Reaction Using Carbonyl Compounds

AbstractA metal‐free one‐pot synthesis route has been documented for the production of 1,1‐unsymmetrical di‐aryl alkanes via reductive Friedel−Crafts alkylation of arenes with carbonyl compounds in 1,1,1,3,3,3,–hexafluoroisopropanol (HFIP) solvent. This approach exhibits a wide substrate scope accommodating diverse functionalities. The transformation of carbonyl compounds into alkylated products is facilitated by dimethylchlorosilane (Me2SiClH) reduction, succeeded via nucleophilic attack of arenes. The established protocol demonstrates a promising strategy for converting indoline‐2,3‐dione into α‐aryl oxindoles with high yields. The reaction involves reduction with Me2SiClH, followed by the attack of arenes in the presence of a TfOH catalyst. The devised protocol offers scalability and remarkable tolerance towards various functional groups. Control experiments provide insights into the reaction mechanism, highlighting the crucial roles of HFIP and Me2SiClH. Furthermore, the method is adaptable for late‐stage functionalization of numerous natural products and pharmaceuticals such as Sesamol, Thymol, Paracetamol, Menthol, and Nerol. Significantly, the technique has proven effective in efficiently synthesising the anticoagulant drug Phenprocoumon and the rodent control agent Coumatetralyl.

Carbonyl Compounds Observed at a Suburban Site during an Unusual Wintertime Ozone Pollution Event in Guangzhou

Carbonyl compounds are important oxygenated volatile organic compounds (VOCs) that play significant roles in the formation of ozone (O3) and atmospheric chemistry. This study presents comprehensive field observations of carbonyl compounds during an unusual wintertime ozone pollution event at a suburban site in Guangzhou, South China, from 19 to 28 December 2020. The aim was to investigate the characteristics and sources of carbonyls, as well as their contributions to O3 formation. Formaldehyde, acetone, and acetaldehyde were the most abundant carbonyls detected, with average concentrations of 7.11 ± 1.80, 5.21 ± 1.13, and 3.00 ± 0.94 ppbv, respectively, on pollution days, significantly higher than those of 2.57 ± 1.12, 2.73 ± 0.88, and 1.10 ± 0.48 ppbv, respectively, on nonpollution days. The Frame for 0-D Atmospheric Modeling (F0AM) box model simulations revealed that local production accounted for 62–88% of observed O3 concentrations during the pollution days. The calculated ozone formation potentials (OFPs) for various precursors (carbonyls and VOCs) indicated that carbonyl compounds contributed 32.87% of the total OFPs on nonpollution days and 36.71% on pollution days, respectively. Formaldehyde, acetaldehyde, and methylglyoxal were identified as the most reactive carbonyls, and formaldehyde ranked top in OFPs, and it alone contributed 15.92% of total OFPs on nonpollution days and 18.10% of total OFPs on pollution days, respectively. The calculation of relative incremental reactivity (RIR) indicates that ozone sensitivity was a VOC-limited regime, and carbonyls showed greater RIRs than other groups of VOCs. The model simulation showed that secondary formation has a significant impact on formaldehyde production, which is primarily controlled by alkenes and biogenic VOCs. The characteristic ratios and backward trajectory analysis also indicated the indispensable impacts of local primary sources (like industrial emissions and vehicle emissions) and regional sources (like biomass burning) through transportation. This study highlights the important roles of carbonyls, particularly formaldehyde, in forming ozone pollution in megacities like the Pearl River Delta region.

Access to Diverse Carbonyl Compounds by Catalyst-Free and Photoinduced Aerobic Cleavage of C=N Bonds.

Functional group interconversion is of great significance in organic synthesis. However, aerobic cleavage of C=N bonds to access carbonyl compounds still suffered from some limitations such as harsh reaction conditions, stoichiometric oxidants, poor substrate scope and use of toxic reagents. Herein, we report a catalyst-free and photo-induced aerobic cleavage of C=N bonds to afford diverse carbonyl compounds using oxygen from air as green oxidant. This mild methodology permits N-tosylhydrazones converted into the corresponding carbonyl compounds including ketones, aldehydes and carboxylic acids, showing broad functional group tolerance and compatibility. Moreover, the gram-scale reaction and post-modification of complicated molecules proved the applicability and efficiency of this strategy. Finally, a plausible mechanism was proposed based on spectroscopic investigations and detailed mechanistic studies.

Cyclization Strategies in Carbonyl–Olefin Metathesis: An Up-to-Date Review

The metathesis reaction between carbonyl compounds and olefins has emerged as a potent strategy for facilitating swift functional group interconversion and the construction of intricate organic structures through the creation of novel carbon–carbon double bonds. To date, significant progress has been made in carbonyl–olefin metathesis reactions, where oxetane, pyrazolidine, 1,3-diol, and metal alkylidene have been proved to be key intermediates. Recently, several reviews have been disclosed, focusing on distinct catalytic approaches for achieving carbonyl–olefin metathesis. However, the summarization of cyclization strategies for constructing aromatic heterocyclic frameworks through carbonyl–olefin metathesis reactions has rarely been reported. Consequently, we present an up-to-date review of the cyclization strategies in carbonyl–olefin metathesis, categorizing them into three main groups: the formation of monocyclic compounds, bicyclic compounds, and polycyclic compounds. This review delves into the underlying mechanism, scope, and applications, offering a comprehensive perspective on the current strength and the limitation of this field.

Diastereoselective Synthesis of Highly Functionalized γ-Lactams via Ugi Reaction/Michael Addition.

The γ-lactam ring is a prominent feature in medicinal chemistry, and its synthesis has garnered significant interest due to its valuable properties. Among the γ-lactams, 2-oxopyrrolidine-3-carbonitrile derivatives stand out as versatile synthons that can be readily transformed into a variety of other functional groups. In this work, we successfully synthesized highly functionalized 3-cyano-2-pyrrolidinones with moderate to good overall yields using the Ugi reaction followed by intramolecular Michael addition. The process demonstrated excellent diastereoselectivity and showed good tolerance to a range of isonitriles and carbonyl compounds.

Elucidating the Antiglycation Effect of Creatine on Methylglyoxal-Induced Carbonyl Stress In Vitro.

Advanced glycation end products (AGEs) with multiple structures are formed at the sites where carbonyl groups of reducing sugars bind to free amino groups of proteins through the Maillard reaction. In recent years, it has been highlighted that the accumulation of AGEs, which are generated when carbonyl compounds produced in the process of sugar metabolism react with proteins, is involved in various diseases. Creatine is a biocomponent that is homeostatically present throughout the body and is known to react nonenzymatically with α-dicarbonyl compounds. This study evaluated the antiglycation potential of creatine against methylglyoxal (MGO), a glucose metabolite that induces carbonyl stress with formation of AGEs in vitro. Further, to elucidate the mechanism of the cytoprotective action of creatine, its effect on the accumulation of carbonyl proteins in the cells and the MGO-induced cellular damage were investigated using neuroblastoma cells. The results revealed that creatine significantly inhibits protein carbonylation by directly reacting with MGO, and creatine added to the culture medium suppressed MGO-derived carbonylation of intracellular proteins and exerted a protective effect on MGO-induced cytotoxicity. These findings suggest that endogenous and supplemented creatine may contribute to the attenuation of carbonyl stress in vivo.

Revealing OH species in situ generated on low-valence Cu sites for selective carbonyl oxidation

Catalytic oxidation through the transfer of lattice oxygen from metal oxides to reactants, namely the Mars-van Krevelen mechanism, has been widely reported. In this study, we evidence the overlooked oxidation route that features the in situ formation of surface OH species on Cu catalysts and its selective addition to the reactant carbonyl group. We observed that glucose oxidation to gluconic acid in air (21% O2) was favored on low-valence Cu sites according to X-ray spectroscopic analyses. Molecular O2 was activated in situ on Cu0/Cu+ forming localized, adsorbed hydroxyl radicals (*OH) which played the primary reactive oxygen species as confirmed by the kinetic isotope effect (KIE) study in D2O and in situ Raman experiments. Combined with DFT calculations, we proposed a mechanism of O2-to-*OH activation through the *OOH intermediate. The localized *OH exhibited higher selectivity toward glucose oxidation at C1HO to form gluconic acid (up to 91% selectivity), in comparison with free radicals in bulk environment that emerged from thermal, noncatalytic hydrogen peroxide decomposition (40% selectivity). The KIE measurements revealed a lower glucose oxidation rate in D2O than in H2O, highlighting the role of water (H2O/D2O) or its derivatives (e.g., *OH/*OD) in the rate-determining step. After proving the C1-H activation step kinetically irrelevant, we proposed the oxidation mechanism that was characterized by the rate-limiting addition of *OH to C1=O in glucose. Our findings advocate that by maneuvering the coverage and activity of surface *OH, high-performance oxidation of carbonyl compounds beyond biomass molecules can be achieved in water and air using nonprecious metal catalysts.

Controllable Synthesis of Thioacetals/Thioketals and β-Sulfanyl Ketones Mediated by Methanesulfonic Anhydride and Sulfuric Acid Sulfuric Acid from Aldehyde/Acetone and Thiols.

A novel and controllable synthesis of thioacetals/thioketals and β-sulfanyl ketones mediated by the reaction of aldehyde/acetone with thiols has been developed. In this protocol, β-sulfanyl ketones can be generated without the prior preparation of α, β-unsaturated carbonyl compounds. A variety of thiols reacted with aldehyde/acetone and provided the corresponding thioacetals/thioketals and β-sulfanyl ketones in good to excellent yields, respectively. This protocol is operationally simple, mild, and atom-economical, providing controllable access to thioacetals/thioketals and thia-Michael addition products under mild conditions.

Using multi-modal spectroscopy technology and microscopic analysis to explore the regulation of ultra-high pressure heat-assisted treatment on the texture of ready-to-eat shrimp during storage

This study employed multi-modal spectroscopy technology and microscopic analysis to investigate the effects of various treatments on the texture of ready-to-eat (RTE) shrimps during storage. The results indicated that ultra-high pressure heat-assisted treatment (UHP-HAT) significantly improved the texture properties of RTE shrimps while simultaneously reducing the carbonyl and trichloroacetic acid-soluble properties associated with protein oxidative degradation. Furthermore, UHP-HAT resulted in a denser and more ordered protein structure, which contributed to an increased content of bound and immobile water. A partial least squares regression model for texture prediction was developed using data obtained from hyperspectral imaging, demonstrating a strong correlation between spectral information and texture parameters. Additionally, infrared imaging was utilized to elucidate the distribution of functional groups (OH, CO, CH) and carbonyl compounds within the proteins. Overall, the findings suggested that UHP-HAT could effectively delay the deterioration of texture by mitigating protein degradation.

Mechanochemical Synthesis ofβ-Sulfenylated Ketones and Esters.

For the first time, ball milling has been employed in the solvent-free synthesis of sulfur-functionalized materials from thiols and α,β-unsaturated ketones and esters, using potassium carbonate as a transition metal-free catalyst. This environmentally friendly protocol makes use of easily accessible reagents to prepare β-sulfenylated carbonyl compounds with yields exceeding 91% under ambient air and solvent-free conditions. Additionally, this innovative synthetic strategy enables the modification of chalcones, compounds with significant medicinal and synthetic potential. The reactions are efficient and easily scalable to gram quantities, offering substantial benefits for practical applications.

From Meteorite to Life's Building Blocks: A possible Electrochemical Pathway to Amino Acids and Peptide Bonds.

This study explores the electrochemical properties of the carbonaceous Allende CV3 meteorite, focusing on its potential as a Fe-based catalyst derived from Mackinawite iron sulfide for electrocatalytic reactions facilitating nitrogen (N2) fixation into ammonia. Through comprehensive analysis, we not only monitored the evolution of key compounds such as CN-, sulfur/H2S, H2 and carbonyl compounds, but also identified potential reagent carriers, indicating significant implications for the Strecker synthesis of amino acids in space environments. Initial examination revealed the presence of polypeptides, notably sequences including dimer Ala-α-HO-Gly, pentamer Gly3-Ala2, and hexamer Gly4-(HO-Gly)2. These discoveries greatly enhance our understanding of astrobiological chemistry, offering valuable insights into prebiotic processes and the potential presence of life-building blocks throughout the universe.

Effect of 1,4-Napthaquinone (NQ) and benzophenone (BPH)on the photodegradation and biodegradation of methyl cellulose film

The induced photodegradation of methyl cellulose (MC) films in air was investigated in the absence and presence of aromatic carbonyl compounds(photosenssitizers): 1,4-naphthaquinone (NQ) and benzophenone (BPH) by accelerated weathering tester. The addition of (0.01 wt %) of low molecular weight aromatic carbonyl compounds to cellulose derivatives films(25µm in thickness) enhanced the photodegradation of the polymer films.The photodegradation rate was measured by the increase in carbonyl absorbance. Decreases in solution viscosity and reduction of molecular weight were also observed in the irradiated samples. Changes in the number-average chain scission, the degree of deterioration and in the quantum yield of chain scission values are also observed, and it was concluded that branching or cross-linking has occurred for cellulose derivative with NQ and BPH. Findings from all analytical techniques indicated that the 1,4-naphthaquinone (NQ) photosensitizer enhance the photodegradation of methyl cellulose more than benzophenone (BPH). The effect of the photosensitizer concentration, (ranging from 0.01 to 0.1 %), on the rate of photodegradation was also monitored for MC films. The rates are increased with increasing the photosensitizer concentration. The effect of film thickness is also studied at fixed sensitizer concentration (0.05%), and results show that the rate of cellulose derivative photodegradation decreases with increasing film thickness. The rate constants of the photodegradation of the photosensitizers deduced in cellulose derivatives films, [at concentration of (0.1%)by weight and thickness (25µm)]. Biodegradation of irradiated cellulose derivatives films was conclusively established with bacteria type Pseudomonas aeuroginosa Rb-19 isolated from crude oil. The amount of bacteria growth on MC after 30 days was lower, while there was no growth observed in MC with BPH

Investigating the efficacy of naphthalene-thiazole hybrid hydrazones as α-glucosidase inhibitors

In this study, a series of hydrazone derivatives containing naphthalene and thiazole hybrids were synthesized through the condensation of (E)-4-methyl-2-(2-(naphthalen-1-ylmethylene)hydrazineyl) thiazole-5-carbohydrazide with various carbonyl compounds, including aldehydes and ketones, whether carbocyclic aromatic or heterocyclic, using a grinding method with drops of acetic acid. The elucidation of the structures of the synthesized hydrazone derivatives was achieved through the analysis of NMR, IR, and mass spectrometry data. All the newly prepared compounds were assessed for their in vitro α-glucosidase inhibition profiles and the results revealed a diverse range of inhibitory potentials, ranging from 9.3 ± 1.0 to 70.5 ± 1.8 μM, in contrast to the reference acarbose (with an IC50 value of 45.2 ± 1.3 μM). In an attempt to explain the observed inhibitions of synthesized naphthalene containing thiazole compounds, molecular docking was performed to determine the binding modes between the synthesized compounds from one side and the active residues of α-glucosidase from the other side. Compounds 4d, 4e, 4c, and 8 demonstrated the strongest binding affinities, with binding energies of -10.5, -9.8, -9.6, and -9.5 kcal/mol, respectively.