Introduction Of Carbonyl Groups Research Articles

Rhodium Catalyzed Carbonylative Approaches for Heterocycles Synthesis

AbstractDuring the past few decades, carbonylative heterocyclic chemistry have acquired a significant chemical alteration for both academic as well as industrial research. Carbonylative heterocycles are commonly used in organic synthesis and fine chemicals preparation. Introduction of carbonyl group can surge the carbon number of parent molecules in the carbonylation reaction. Herein, we have summarized the main developments achieved on rhodium catalyst from last 20 years in the area of carbonylative heterocyclic synthesis.

Ultralong Organic Phosphorescence Modulation of Aromatic Carbonyls and Multi‐Component Systems

Comprehensive SummaryAromatic carbonyls have evoked sustained attention in the field of room‐temperature phosphorescence (RTP). The introduction of carbonyl groups is a general way to achieve RTP for their effective intersystem crossing (ISC) by improving spin‐orbit coupling (SOC). With further molecular design and processing strategies, aromatic carbonyls materials with multi‐functional and high efficiency ultralong organic phosphorescence (UOP) can be obtained. This review summarizes the mechanism of aromatic carbonyls with UOP in pure aromatic carbonyls and their multi‐component systems. Some detailed strategies for improving UOP performance are further introduced. The summary and outlook are presented to expound on the advances and lack of aromatic carbonyls. Further development directions and requirements are also put forward.

A Permanent Porous Hydrogen-Bonded Framework with Room-Temperature Phosphorescence

Hydrogen-bonded organic frameworks (HOFs) based on metal-free organic materials with permanent porosity and phosphorescence are rarely reported. Herein, we report a pure organic phosphor of 1,3,5-tris((4-(9H-carbazol-9-yl)phenyl)methanone-1-yl)benzene (BPMCz) as a suitable building block to construct robust HOF materials. Apart from a good thermal stability, BPMCz-P1 exhibited a comparatively high CO2 adsorption and room-temperature phosphorescence with a lifetime of 1.8 ms under ambient conditions. The experimental and theoretical data clearly indicate that aromatic carbonyl groups not only play a critical role in forming intermolecular hydrogen bonds to construct HOFs but also facilitate π–π interactions to enable long-lived phosphorescence. The introduction of carbonyl groups in BPMCz-P1 successfully construct a metal-free porous framework with phosphorescence emission. This study will not only provide valuable guidelines for the construction of new HOFs with luminescent properties but also expand the scope of organic room-temperature phosphorescent materials and their applications.

Modification of softwood kraft pulp fibres using hydrogen peroxide at acidic conditions

The aim of this work was to provide softwood kraft pulp fibres with new functionalities by the introduction of carbonyl groups. Carbonyl groups are known to affect properties such as wet strength through the formation of covalent bonds, i.e. hemiacetals. The method developed involves oxidation using hydrogen peroxide at mildly acidic conditions. It was found that the carbonyl group content increased with both increasing temperature and residence time when oxidized at acidic conditions. The number of carboxylic groups, however, remained approximately constant. There was virtually no increase in carbonyl groups when oxidation was performed at alkaline conditions. The maximum increase in carbonyl groups was found at a residence time of 90 min, a reaction temperature of 85 °C and a pH of 4. These conditions resulted in an increase in carbonyl groups from 30 to 122 µmol/g. When formed into a sheet, the pulp oxidized at acidic conditions proved to maintain its structural integrity at aqueous conditions. This indicates the formation of hemiacetal bonds between the introduced carbonyl groups and the hydroxyl groups on the carbohydrate chains. Thus, a possible application for the method could be fibre modification during the final bleaching stage of softwood kraft pulp, where the wet strength of the pulp could be increased.

Identification of oxidant susceptible proteins in Salmonella Typhimurium.

The human gut pathogen, Salmonella Typhimurium (S. Typhimurium) not only survives but also replicates inside the phagocytic cells. Bacterial proteins are the primary targets of phagocyte generated oxidants. Because of the different amino acid composition, some proteins are more prone to oxidation than others. Many oxidant induced modifications to amino acids have been described. Introduction of carbonyl group is one of such modifications, which takes place quite early following exposure of proteins to oxidants and is quite stable. Therefore, carbonyl groups can be exploited to identify oxidant susceptible proteins. Hypochlorous acid (HOCl) is one of the most potent oxidants produced by phagocytes. Incubation of S. Typhimurium with 3mM HOCl resulted in more than 150 folds loss of bacterial viability. Proteins extracted from HOCl exposed S. Typhimurium cells showed about 60 folds (p < 0.001) more carbonyl levels as compared to unexposed cells. Similarly, 2, 4-Dinitrophenylhydrazine (2, 4-DNPH) derivatized proteins of HOCl treated S. Typhimurium cultures reacted strongly with anti-DNP antibodies as compared to buffer treated counterpart. Next, we have derivatized carbonyl groups on the proteins with biotin hydrazide. The derivatized proteins were then isolated by avidin affinity chromatography. Mass spectrometry based analysis revealed the presence of 204 proteins.

Optimization and preclinical evaluation of novel histamine H3receptor ligands: Acetyl and propionyl phenoxyalkyl piperazine derivatives.

As a continuation of our search for novel histamine H3 receptor ligands, a series of new acetyl and propionyl phenoxyalkylamine derivatives (2-25) was synthesized. Compounds with three to four carbon atoms alkyl chain spacer, composed of six various 4N-substituted piperazine moieties were evaluated for their binding properties at human histamine H3 receptors (hH3R). In vitro test results proved the 4-pyridylpiperazine moiety as crucial element for high hH3R affinity (hH3R Ki = 5.2-115 nM). Moreover introduction of carbonyl group containing residues in the lipophilic part of molecules instead of branched alkyl substituents resulted in increased affinity in correlation to previously described series, whereas propionyl derivatives showed slightly higher affinities than those of acetyl (16 and 22vs.4 and 10; hH3R Ki = 5.2 and 15.4 nM vs. 10.2 and 115 nM, respectively). These findings were confirmed by molecular modelling studies, demonstrating multiple ligand-receptor interactions. Furthermore, pharmacological in vivo test results of compound 4 clearly indicate that it may affect the amount of calories consumed, thus act as an anorectic compound. Likewise, its protective action against hyperglycemia and the development of overweight has been shown. In order to estimate drug-likeness of compound 4, in silico and experimental evaluation of metabolic stability in human liver microsomes was performed.

Water‐based polyurethane dispersions

AbstractA general overview is presented of the most relevant and commercially available aqueous polyurethane dispersions (PUDs) and their typical properties. This paper starts with the chemistry and the general composition of standard PUDs and subsequently urethane–acrylic hybrid dispersions are presented with special emphasis on the relation between the obtained morphology and the final material properties. In a section regarding crosslinkable PUDs, the two most frequently applied curing mechanisms are mentioned: firstly the introduction of carbonyl groups into PUDs which can be used for curing at room temperature with amino functional compounds by formation of azomethine moieties, and secondly the introduction of unsaturated fatty acid moieties into PUDs, which enable oxidative curing at ambient conditions. The paper then continues with a section on UV‐curable, acryloyl‐functional PUDs, followed by a section on an interesting new development, namely water‐based polyurethanes with special optic and haptic properties. The paper ends with a section on recently reported modifications of PUDs, including carbon nanotube‐ and graphene‐modified PUDs, PUDs modified with silane coupling agents and PUDs modified with biodegradable moieties. © 2018 Society of Chemical Industry

Pyridoxamine scavenges protein carbonyls and inhibits protein aggregation in oxidative stress-induced human HepG2 hepatocytes

Introduction of carbonyl groups into amino acid residues is a hallmark for oxidative damage to proteins by reactive oxygen species (ROS). Protein carbonylation can have deleterious effects on cell function and viability, since it is generally unrepairable by cells and can lead to protein dysfunction and to the production of potentially harmful protein aggregates. Meanwhile, pyridoxamine (PM) is known to scavenge various toxic carbonyl species derived from either glucose or lipid degradation through nucleophilic addition. PM is also demonstrated to catalyze non-enzymatic transamination reactions between amino and α-keto acids. Here, we found that PM scavenges protein carbonyls in oxidized BSA with concomitant generation of pyridoxal and recovers oxidized lysozyme activity. Moreover, we demonstrated that the treatment of H2O2-exposed HepG2 hepatocytes with PM significantly reduced levels of cellular carbonylated proteins and aggregated proteins, and also improved cell survival rate. Our results suggest that PM may have potential efficacy in ameliorating ROS-mediated cellular dysfunction.

Introduction of Carbonyl Groups: An Approach to Enhance Electrochemical Performance of Conjugated Dicarboxylate for Li-Ion Batteries

A rational functionalization of conjugated dicarboxylate is reported here to enhance the cyclability and rate capability for Li-ion batteries. Introduction of carbonyl groups between aromatic rings is explored as an alternative way to extend π-conjugation. For the proof of concept, 4,4′-bis(lithiooxycarbonyl)benzil (Li2-BZL) was synthesized and compared its lithium storage performance against lithium [1,1′-biphenyl]-4,4′-dicarboxylate (Li2-BPDC). The Li2-BZL electrode delivers a stable capacity of 165 mAh g−1 even after 50 cycles at current density of 50 mAh g−1 whereas, rapid capacity fading was observed in the case of Li2-BPDC. Density functional theory (DFT) studies confirmed that the carbonyl groups in the Li2-BZL to reduce the bandgap, thereby improving the elctrochemical lithium storage performance of Li2-BZL electrode in comparision to that of Li2-BPDC.

Modified disordered carbon prepared from 3,4,9,10-perylenetetracarboxylic dianhydride as an anode material for Li-ion batteries

To prepare an anode material for Li-ion batteries with high discharge capacity and good cycling stability, disordered carbon (DC) formed by calcinations of 3,4,9,10-perylenetetracarboxylic dianhydride was modified via an acid treatment using a mixture of HNO3 and H2SO4. The modified disordered carbon (MDC) was characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET) analysis, and scanning electron microscopy (SEM). FTIR spectra confirm the successful introduction of carbonyl groups onto the DC surface. Some pores appear in the columnar structure of MDC, as observed in SEM micrographs. Li+ ions intercalation/deintercalation is facilitated by the modified morphology. Electrochemical tests show that the MDC exhibits a significant improvement in discharge capacity and cycling stability. These results indicate that the MDC has strong potential for use as an anode material in Li-ion batteries.

Green Emission in Ladder‐Type Quarterphenyl: Beyond the Fluorenone‐Defect

In polyfluorenes it is generally accepted that (photo)degradation leads to fluorenone type defects that accept the excitation energy and emit green‐to‐yellow light with rather low efficiency. Although initial spectroscopic studies suggest the same to hold true for ladder‐type poly(para‐phenylene)s (LPPPs), kinetic studies of the degradation process are not compatible with the established mechanism. In general, the observed green emission can be caused by the introduction of carbonyl groups; however, only if associated with an additional disruption of the backbone rigidity and hence planarity of the entire π‐system. This is clearly shown by comparison with synthesized model compounds, which are bearing the fluorenone motif yet possess very different optical properties as compared to the defects, which are actually formed. Degradation can be caused by solvent specific, yet substrate nonspecific aromatic formylation but mainly originates from reaction with in‐situ generated singlet oxygen, both in solution as well as in thin films. Time‐dependent photoluminescence measurements on thin films show that green emission is enhanced by energy transfer from intact molecules to defect centers.

Effect of sonochemical treatments on the integrity and oxidation state of cellulose

The sonochemical degradation of cellulose by a 24-kHz ultrasound probe system and the oxidative modification of cellulose upon sonication were studied. Both aqueous cellulose suspension (heterogeneous system) as well as cellulose solutions in N,N-dimethylacetamide/LiCl (homogeneous system) were used. In both cases, a significant reduction in the degree of polymerization was observed. The rate of the degradation process was dependent on the degree of polymerization of the starting material, temperature, cellulose amount in suspension, cellulose concentration in solution, and the pH value of the aqueous suspension. In solution, the degradation process was accompanied by cellulose oxidation as seen in the introduction of carbonyl groups. The introduction of carbonyl groups could be shown to occur close to chain ends. Sonochemical degradation of cellulose is a very efficient non-classical method in accordance with “green chemistry” concepts.

Lack of transketolase-like (TKTL) 1 aggravates murine experimental colitis

Transketolase-like (TKTL) 1 indirectly replenishes NADPH preventing damage induced by reactive oxygen species (ROS) formed upon intestinal inflammation. We investigated the function of TKTL1 during murine colitis and ROS detoxification for prevention of tissue damage. Mucosal damage in TKTL1(-/-) and wild-type (WT) mice was assessed by miniendoscopy and histology during dextran sodium sulfate (DSS) colitis. mRNA levels of interferon (IFN)-γ, inducible nitric oxide synthase (iNOS), interleukin (IL)-6, tumor necrosis factor (TNF), transketolase (TKT), and TKTL2 were determined by PCR and/or Western blotting. To assess oxidative and nitrosative stress nitrosylation, carbonylation and antioxidative enzymes catalase (Cat), superoxide dismutase 1 and 2, as well as glutathione (GSH) were determined. Myeloperoxidase (MPO) was determined for assessment of tissue neutrophils. TKTL1 knockout or DSS treatment did not influence TKT and TKTL2 mRNA or protein expression. Mucosal damage was significantly increased in TKTL1(-/-) mice indicated by miniendoscopy as well as a significantly shorter colon and more severe histological scores compared with WT mice during DSS colitis. This was associated with higher mRNA levels of IFN-γ, iNOS, IL-6, and TNF. In addition, iNOS protein expression was significantly enhanced in TKTL1(-/-) mice as well as MPO activity. Protein modification by nitric oxide (nitrotyrosine) was induced in TKTL1(-/-) mice. However, introduction of carbonyl groups by ROS was not induced in these mice. The expression of SOD1, SOD2, Cat, as well as GSH content was not significantly changed in TKTL1(-/-) mice. We conclude that induced colitis in TKTL1(-/-) mice was more severe compared with WT. This indicates a role of TKTL1 during mucosal repair and restoration.

Synthesis and properties of all solid polymer electrolytes based on poly(vinyl acetate-co-acetyl ethylene oxide acrylate)

Poly(acetyl ethylene oxide acrylate-co-vinyl acetate) (P(AEOA-VAc)) was synthesized and used as a host for lithium perchlorate to prepare an all solid polymer electrolyte. Introduction of carbonyl groups into the copolymer increased ionic conductivity. All solid polymer electrolytes based on P(AEOA-VAc) at 14.3 wt% VAc with 12wt% LiClO4 showed conductivity as high as 1.2 × 10−4 S cm−1 at room temperature. The temperature dependence of the ionic conductivity followed the VTF behavior, indicating that the ion transport was related to segmental movement of the polymer. FTIR was used to investigate the effect of the carbonyl group on ionic conductivity. The interaction between the lithium salt and carbonyl groups accelerated the dissociation of the lithium salt and thus resulted in a maximum ionic conductivity at a salt concentration higher than pure PAEO-salts system. Copyright © 2010 John Wiley & Sons, Ltd.

Introduction of carbonyl group to sugars using pyranose 2-oxidase-immobilized membrane

To introduce the carbonyl group to sugars in a continuous process, pyranose 2-oxidase was immobilized on a poly(vinylidene fluoride) membrane by hydrophobic interaction, and sugar solutions were passed through the membrane. The amount of immobilized pyranose 2-oxidase reached 14 mg g −1 in 1 h in permeation mode. With increase in the space velocity of the solution of one of the sugars used (sucrose), the reactivity of the membrane decreased, indicating that the space velocity of the system should be less than 10 h −1. Glucose, sucrose, and dextran solutions were circulated through the enzyme-immobilized membrane. Glucose and sucrose were completely converted to keto-glucose and keto-sucrose in 75 and 225 h, respectively, whereas dextran was not converted. The operational and storage stabilities were investigated using glucose as substrate, resulting that relative activity of pyranose 2-oxidase immobilized onto Durapore was kept for 7 days. The membrane system immobilizing pyranose 2-oxidase is thus effective for conversion of monosaccharides or disaccharides by introduction of carbonyl groups.

Plasma carbonyls do not correlate with lung function or computed tomography measures of lung density in older smokers

Oxidative stress and inflammation are hallmarks of chronic obstructive pulmonary disease (COPD). A critical byproduct of oxidative damage is the introduction of carbonyl groups into amino acid residues. We hypothesize that plasma carbonyl content is inversely correlated with lung function and computed tomography (CT) measures of lung density among smokers and is elevated in COPD. Carbonyl was measured in plasma of participants aged 60 years and older by ELISA. Generalized linear and additive models were used to adjust for potential confounders. Among 541 participants (52% male, mean age 67 years, 41% current smokers), mean plasma carbonyl content was 17.9±2.9 nmol ml−1 and mean forced expiratory volume in one second (FEV1) was 80.7±20.9% of predicted. Plasma carbonyl content was inversely associated with FEV1, but this relationship was largely explained by age. Multivariate analyses ruled out clinically meaningful associations of plasma carbonyl content with FEV1, FEV1/FVC (forced vital capacity) ratio, severity of airflow obstruction, and CT lung density. Plasma carbonyl content is a poor biomarker of oxidative stress in COPD and emphysema.

Copper Corrosion: Comparison between Naturally Aged Papers and Artificially Aged Model Papers

AbstractSummary: Copper corrosion on paper works of art is commonly explained by copper ion‐catalysed cellulose oxidation, usually reflected by discoloration of pigment and surrounding paper as well as by loss of mechanical strength. In this study, model paper and historic paper samples, both containing copper pigments, were compared using fluorescence labelling of carbonyl groups and subsequent GPC analysis. The historic paper samples did not show any typical sign of copper pigment induced discoloration, but high brittleness. In artificially copper‐corroded paper samples the distribution of carbonyl groups in combination with the molecular weight distribution of cellulose clearly indicated the occurrence of oxidative processes. In contrast, only insignificant oxidative damage was detected in the case of the paper fragments from an original work of art, a codex from the 15th century. Here, mostly degradation by hydrolytic action was revealed. There was no introduction of carbonyl groups into the bulk section of the molecular weight distribution, and the gain in new carbonyl groups corresponded to the number of reducing end groups newly generated by hydrolysis.

Oxidative modification of proteins during aging.

Accumulating experimental evidence supports the proposal that many of the changes which occur during aging are a consequence of oxidative damage. Reactive oxygen species react with all three of the major cellular macromolecules, nucleic acids, lipids, and proteins. This minireview focuses on proteins as targets of oxidizing species during aging. Many of the reactions mediated by these oxidizing species result in the introduction of carbonyl groups into proteins. The steady-state level of carbonyl-bearing proteins increases exponentially during the last third of lifespan in animals ranging from C. elegans to man. Genetic and non-genetic manipulations which lengthen lifespan cause a decrease in the level of protein carbonyl while those which shorten lifespan increase the level. Oxidized proteins bearing carbonyl groups are generally dysfunctional, and in the last third of lifespan the content of these oxidized proteins rises to a level likely to cause substantial disruption of cellular function.

Histone carbonylation in vivo and in vitro

Non-enzymic damage to nuclear proteins has potentially severe consequences for the maintenance of genomic integrity. Introduction of carbonyl groups into histones in vivo and in vitro was assessed by Western blot immunoassay and reductive incorporation of tritium from radiolabelled NaBH4 (sodium borohydride). Histone H1 extracted from bovine thymus, liver and spleen was found to contain significantly elevated amounts of protein-bound carbonyl groups as compared with core histones. The carbonyl content of nuclear proteins of rat pheochromocytoma cells (PC12 cells) was not greatly increased following oxidative stress induced by H2O2, but was significantly increased following alkylating stress induced by N-methyl-N´-nitro-N-nitrosoguanidine or by combined oxidative and alkylating stress. Free ADP-ribose, a reducing sugar generated in the nucleus in proportion to DNA strand breaks, was shown to be a potent histone H1 carbonylating agent in isolated PC12 cell nuclei. Studies of the mechanism of histone H1 modification by ADP-ribose indicate that carbonylation involves formation of a stable acyclic ketoamine. Our results demonstrate preferential histone H1 carbonylation in vivo, with potentially important consequences for chromatin structure and function.

Histone carbonylation in vivo and in vitro

Non-enzymic damage to nuclear proteins has potentially severe consequences for the maintenance of genomic integrity. Introduction of carbonyl groups into histones in vivo and in vitro was assessed by Western blot immunoassay and reductive incorporation of tritium from radiolabelled NaBH(4) (sodium borohydride). Histone H1 extracted from bovine thymus, liver and spleen was found to contain significantly elevated amounts of protein-bound carbonyl groups as compared with core histones. The carbonyl content of nuclear proteins of rat pheochromocytoma cells (PC12 cells) was not greatly increased following oxidative stress induced by H(2)O(2), but was significantly increased following alkylating stress induced by N-methyl-N'-nitro-N-nitrosoguanidine or by combined oxidative and alkylating stress. Free ADP-ribose, a reducing sugar generated in the nucleus in proportion to DNA strand breaks, was shown to be a potent histone H1 carbonylating agent in isolated PC12 cell nuclei. Studies of the mechanism of histone H1 modification by ADP-ribose indicate that carbonylation involves formation of a stable acyclic ketoamine. Our results demonstrate preferential histone H1 carbonylation in vivo, with potentially important consequences for chromatin structure and function.