Bibliografie tematiche / Carbonyl compounds

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Letteratura scientifica selezionata sul tema "Carbonyl compounds"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 28 luglio 2024

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Articoli di riviste sul tema "Carbonyl compounds"

Hu, Yue, Wei Sun e Chao Liu. "Deoxygenative Transformation of Carbonyl and Carboxyl Compounds Using gem-Diborylalkanes". Synlett 30, n. 10 (21 febbraio 2019): 1105–10. http://dx.doi.org/10.1055/s-0037-1611728.

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gem-Diborylalkanes serve as privileged carbanion precursors for the efficient construction of carbon–carbon bond with various carbonyl and carboxyl compounds. We highlight the recent advances on deoxygenative transformation of carbonyl and carboxyl compounds using gem-diborylalkanes reagents. Our recent development of a dual functionalization of gem-diborylalkanes through deoxygenative enolization with the carboxylic acids is also discussed.1 Introduction2 Activation Modes of gem-Diborylalkanes3 Deoxygenative Transformation of Carbonyl and Carboxyl Compounds via α-Diboryl Carbanion3.1 Reaction with Aldehyde and Ketone Electrophiles3.2 Reaction with Carboxylic Acid Derivatives4 Deoxygenative Transformation of Carbonyl and Carboxyl Compounds via α-Monoboryl Carbanion5 Conclusion

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Epstein, S. A., E. Tapavicza, F. Furche e S. A. Nizkorodov. "Direct photolysis of carbonyl compounds dissolved in cloud and fog droplets". Atmospheric Chemistry and Physics Discussions 13, n. 4 (24 aprile 2013): 10905–37. http://dx.doi.org/10.5194/acpd-13-10905-2013.

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Abstract. Gas phase photolysis is an important tropospheric sink for many carbonyl compounds, however the significance of direct photolysis of carbonyl compounds dissolved in cloud and fog droplets is uncertain. We develop a theoretical approach to assess the importance of aqueous photolysis for a series of carbonyls that possess carboxyl and hydroxyl functional groups by comparison with rates of other atmospheric processes. We use computationally and experimentally derived Henry's law parameters, hydration equilibrium parameters, aqueous hydroxyl radical (OH) rate constants, and optical extinction coefficients to identify types of compounds that will not have competitive aqueous photolysis rates. We also present molecular dynamics simulations of atmospherically relevant carbonyl compounds designed to estimate gas and aqueous phase extinction coefficients. In addition, experiments designed to measure the photolysis rate of glyceraldehyde, an atmospherically relevant water soluble organic compound, reveal that aqueous quantum yields are highly molecule-specific and cannot be extrapolated from measurements of structurally similar compounds. We find that only three out of the 92 carbonyl compounds investigated, pyruvic acid, 3-oxobutanoic acid, and 3-oxopropanoic acid, may have aqueous photolysis rates that exceed the rate of oxidation by dissolved OH. For almost all carbonyl compounds lacking α, β conjugation, atmospheric removal by direct photolysis in cloud and fog droplets can be neglected.

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Vizer, S. A., e K. B. Yerzhanov. "Heterocycles Synthesis at Carbonylation of Acetylenic Compounds". Eurasian Chemico-Technological Journal 5, n. 2 (5 aprile 2016): 145. http://dx.doi.org/10.18321/ectj294.

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The carbonylation of unsaturated hydrocarbons, alcohols, organic halides and other substrates catalyzed by transition metals, salts of transition metals and organometallic complexes is a wide used synthesis method of new carbonyl, carboxyl and alkoxy carbonyl containing compounds including creation or modificationt of heterocycles. The data about synthesis of heterocycles at carbonylation of acetylenic compounds have been appeared at last 20 years and are demonstrated in our review. Introduction of carbon monoxide in the catalytic reactions of acetylenic compounds permits to obtain in oneput process the diverse heterocycles, having carbonyl, carboxyl or alkoxycarbonyl substitutes or containing these fragments inside of heterocycles.

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Epstein, S. A., E. Tapavicza, F. Furche e S. A. Nizkorodov. "Direct photolysis of carbonyl compounds dissolved in cloud and fog~droplets". Atmospheric Chemistry and Physics 13, n. 18 (26 settembre 2013): 9461–77. http://dx.doi.org/10.5194/acp-13-9461-2013.

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Abstract. Gas-phase photolysis is an important tropospheric sink for many carbonyl compounds; however the significance of direct photolysis of these compounds dissolved in cloud and fog droplets is uncertain. We develop a theoretical approach to assess the importance of aqueous photolysis for a series of carbonyls that possess carboxyl and hydroxyl functional groups by comparison with rates of other atmospheric processes. We use computationally and experimentally derived effective Henry's law constants, hydration equilibrium parameters, aqueous hydroxyl radical (OH) rate constants, and optical extinction coefficients to identify types of compounds that will (or will not) have competitive aqueous photolysis rates. We also present molecular dynamics simulations designed to estimate gas- and aqueous-phase extinction coefficients of unstudied atmospherically relevant compounds found in d-limonene and isoprene secondary organic aerosol. In addition, experiments designed to measure the photolysis rate of glyceraldehyde, an atmospherically relevant water-soluble organic compound, reveal that aqueous quantum yields are highly molecule-specific and cannot be extrapolated from measurements of structurally similar compounds. We find that only two out of the 92 carbonyl compounds investigated, pyruvic acid and acetoacetic acid, may have aqueous photolysis rates that exceed the rate of oxidation by dissolved OH. For almost all carbonyl compounds lacking α,β-conjugation that were investigated, atmospheric removal by direct photolysis in cloud and fog droplets can be neglected under typical atmospheric conditions.

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Hellén, H., H. Hakola, A. Reissell e T. M. Ruuskanen. "Carbonyl compounds in boreal coniferous forest air in Hyytiälä, Southern Finland". Atmospheric Chemistry and Physics 4, n. 7 (8 settembre 2004): 1771–80. http://dx.doi.org/10.5194/acp-4-1771-2004.

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Abstract. A variety of C1-C12 carbonyl compounds were measured in the air of a boreal coniferous forest located in Hyytiälä, Southern Finland. 24-hour samples were collected during March and April in 2003 using DNPH (2,4-dinitrophenyl hydrazine) coated C18-cartridges and analyzed by liquid chromatography-mass spectrometry (LC-MS). Altogether 22 carbonyl compounds were quantified. The most abundant carbonyls were acetone (24-hour average 1340ng/m3), formaldehyde (480ng/m3) and acetaldehyde (360ng/m3). Concentrations of monoterpene reaction products nopinone (9ng/m3) and limona ketone (5ng/m3) were low compared to the most abundant low molecular weight carbonyls. Trajectory analysis showed that highest concentrations of carbonyls were measured in the air masses coming from the East and the lowest in the air masses cycled long time over Scandinavia. The total concentration of carbonyl compounds in Hyytiälä in March/April 2003 was much higher than the concentration of aromatic hydrocarbons and monoterpenes in April 2002. Scaling the concentrations against reactivity with the OH-radical showed, that in spite of relatively low ambient concentrations higher molecular weight aldehydes contribute significantly to the total OH-reactive mass of carbonyls. The impact of carbonyl compounds on OH-radical chemistry is important. Contribution of carbonyls as an OH sink is comparable to that of NO2 and higher than monoterpenes and aromatic hydrocarbons. Lifetimes of the measured carbonyls with respect to reactions with OH radicals, ozone (O3), and nitrate (NO3) radicals as well as photolysis were estimated. The main sink reactions for most of the carbonyl compounds in Hyytiälä in springtime are expected to be reactions with the OH radical and photolysis. For 6-methyl-5-hepten-2-one and limona ketone also reactions with ozone are important. The sources of carbonyl compounds are presently highly uncertain. Based on the comparisons with urban concentrations the direct anthropogenic emissions are not as important as secondary biogenic and anthropogenic sources or primary biogenic sources in Hyytiälä.

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Wang, Jinhe, Shan Chen, Xiaoguo Qiu, Wenya Niu, Ouyang Li, Chao Zhu, Xi Zhang, Xue Yang e Guiqin Zhang. "Pollution Characteristics of Atmospheric Carbonyl Compounds in a Large City of Northern China". Journal of Chemistry 2022 (24 gennaio 2022): 1–13. http://dx.doi.org/10.1155/2022/3292598.

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To better understand the pollution characteristics and formation mechanisms of atmospheric carbonyl compounds, continuous measurements of carbonyl compounds in Jinan were taken for one month at a sampling frequency of 2 h. The sources, pollution characteristics, and concentration changes of carbonyl compounds during the summers of 2018 and 2020 were compared. The total concentrations of carbonyl compounds were 10.51 ± 0.13 ppbV and 6.30 ± 1.08 ppbV in 2018 and 2020, respectively. In both years, formaldehyde, acetone, and acetaldehyde were the major carbonyls. Diurnal variations and correlation analyses showed that exhaust emissions from motor vehicles during peak traffic periods significantly contributed to the concentrations of carbonyl compounds in Jinan, with formaldehyde exhibiting net production. The ratio of formaldehyde/acetaldehyde (C1/C2) was 2.64 in 2018 and 2.03 in 2020, indicating that carbonyl compounds are jointly affected by anthropogenic sources and photochemical reactions. Master Chemical Mechanism model analyses showed that the formation of formaldehyde in Jinan was controlled by RO + O2 reactions, and formaldehyde was mainly consumed via photolysis and its reaction with the hydroxyl radical. In situ photochemistry can further promote formaldehyde production. The comparison of the reactivities of different carbonyl compounds revealed that formaldehyde, acetaldehyde, butyraldehyde, and propionaldehyde play an important role in hydroxyl radical reactions and ozone generation. Among all the measured carbonyl compounds, benzaldehyde contributed the most to secondary organic aerosols (SOAs). Overall, this study provides new insights into the formation mechanisms of carbonyl compounds as well as their pollution characteristics.

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Hellén, H., H. Hakola, A. Reissell e T. M. Ruuskanen. "Carbonyl compounds in boreal coniferous forest air in Hyytiälä, Southern Finland". Atmospheric Chemistry and Physics Discussions 4, n. 3 (3 giugno 2004): 2991–3011. http://dx.doi.org/10.5194/acpd-4-2991-2004.

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Abstract. A variety of C1-C12 carbonyl compounds were measured in the air of a boreal coniferous forest located in Hyytiälä, Southern Finland. 24-h samples were collected during March and April in 2003 using DNPH (2,4-dinitrophenyl hydrazine) coated C18-cartridges and analyzed by liquid chromatography-mass spectrometry (LC-MS). Altogether 22 carbonyl compounds were quantified. The most abundant carbonyls were acetone (24-h average 1340 ng/m3), formaldehyde (480 ng/m3) and acetaldehyde (360 ng/m3). In contrast, scaling of concentrations against reactivity with the hydroxyl (OH) radical significantly increased the contribution of larger aldehydes and ketones (e.g. decanal, octanal and 6-methyl-5-hepten-2-one). Concentrations of monoterpene reaction products nopinone (9 ng/m3) and limona ketone (5 ng/m3) were low compared to the most abundant low molecular weight carbonyls. The total concentration of carbonyl compounds in Hyytiälä in April/March 2003 was much higher than the concentration of aromatic hydrocarbons and monoterpenes in April 2002. Lifetimes of the measured carbonyls with respect to reactions with OH radicals, ozone (O3), and nitrate (NO3) radicals as well as photolysis were estimated. The main sinks for most of the carbonyl compounds in Hyytiälä in springtime are expected to be reactions with the OH radical and photolysis. For 6-methyl-5-hepten-2-one and limona ketone also reactions with ozone are important. The sources of carbonyl compounds are presently highly uncertain. Due to the relatively short lifetimes of aldehydes and ketones, secondary biogenic and anthropogenic sources, that is oxidation of volatile organic compounds, and primary biogenic sources are expected to dominate in Hyytiälä.

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Moldoveanu, S., W. Coleman e J. Wilkins. "Determination of Carbonyl Compounds in Exhaled Cigarette Smoke". Beiträge zur Tabakforschung International/Contributions to Tobacco Research 22, n. 5 (1 giugno 2007): 346–57. http://dx.doi.org/10.2478/cttr-2013-0841.

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AbstractThis paper presents the findings on a quantitative evaluation of carbonyl levels in exhaled cigarette smoke from human subjects. The cigarettes evaluated include products with 5.0 mg ‘tar’, 10.6 mg ‘tar’ and 16.2 mg ‘tar’, where ‘tar’ is defined as the weight of total wet particulate matter (TPM) minus the weight of nicotine and water, and the cigarettes are smoked following U.S. Federal Trade Commission (FTC) recommendations. The measured levels of carbonyls in the exhaled smoke were compared with calculated yields of carbonyls in the inhaled smoke and a retention efficiency was obtained. The number of human subjects included a total of ten smokers for the 10.6 mg ‘tar’, five for the 16.2 mg ‘tar’, and five for the 5.0 mg ‘tar’ product, each subject smoking three cigarettes. The analyzed carbonyl compounds included several aldehydes (formaldehyde, acetaldehyde, acrolein, propionaldehyde, crotonaldehyde and n-butyraldehyde), and two ketones (acetone and 2-butanone). The smoke collection from the human subjects was vacuum assisted. Exhaled smoke was collected on Cambridge pads pretreated with a solution of dinitrophenylhydrazine (DNPH) followed by high performance liquid chromatography (HPLC) analysis of the dinitrophenylhydrazones of the carbonyl compounds. The cigarette butts from the smokers were collected and analyzed for nicotine. The nicotine levels for the cigarette butts from the smokers were used to calculate the level of carbonyls in the inhaled smoke, based on calibration curves. These were generated separately by analyzing the carbonyls in smoke and the nicotine in the cigarette butts obtained by machine smoking under different puffing regimes. The comparison of the level of carbonyl compounds in exhaled smoke with that from the inhaled smoke showed high retention of all the carbonyls. The retention of aldehydes was above 95% for all three different ‘tar’ levels cigarettes. The ketones were retained with a slightly lower efficiency. Acetone was retained in the range of 90% to 95%. The retention for 2-butanone showed a larger scatter compared to other results but it also appeared to be slightly less absorbed than the aldehydes, with an average retention around 95%. The retention of acetaldehyde and acetone by human smokers was previously reported in literature and the findings from this study are in very good agreement with these result.

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Geng, Chunmei, Shijie Li, Baohui Yin, Chao Gu, Yingying Liu, Liming Li, Kangwei Li et al. "Atmospheric Carbonyl Compounds in the Central Taklimakan Desert in Summertime: Ambient Levels, Composition and Sources". Atmosphere 13, n. 5 (8 maggio 2022): 761. http://dx.doi.org/10.3390/atmos13050761.

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Although carbonyl compounds are a key species with atmospheric oxidation capacity, their concentrations and sources have not been sufficiently characterized in various atmospheres, especially in desert areas. In this study, atmospheric carbonyl compounds were measured from 16 May to 15 June 2018 in Tazhong in the central Taklimakan Desert, Xinjiang Uygur Autonomous Region, China. Concentrations, chemical compositions, and sources of carbonyl compounds were investigated and compared with those of different environments worldwide. The average concentration of total carbonyls during the sampling period was 11.79 ± 4.03 ppbv. Formaldehyde, acetaldehyde, and acetone were the most abundant carbonyls, with average concentrations of 6.08 ± 2.37, 1.68 ± 0.78, and 2.52 ± 0.68 ppbv, respectively. Strong correlations between formaldehyde and other carbonyls were found, indicating same or similar sources and sinks. A hybrid single-particle Lagrangian integrated trajectory was used to analyze 72 h back trajectories. The values of C1/C2 (formaldehyde to acetaldehyde, 3.22–4.59) and C2/C3 (acetaldehyde to propionaldehyde, 15.00–17.03) from different directions and distances of the trajectories were consistent with the characteristics of a remote area. Relative to various environments, the carbonyl concentration in the Tazhong desert site was lower than that in urban areas and higher than that in suburban and remote areas, implying contributions from local primary and secondary sources. The obtained data can be used to improve the source and sink estimation of carbonyls at the regional scale.

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He, Zeyu, Yue Hu, Chungu Xia e Chao Liu. "Recent advances in the borylative transformation of carbonyl and carboxyl compounds". Organic & Biomolecular Chemistry 17, n. 25 (2019): 6099–113. http://dx.doi.org/10.1039/c9ob01029g.

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Più fonti

Tesi sul tema "Carbonyl compounds"

Rückriemen, Jana. "Carbonyl Compounds in Manuka Honey:". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-233408.

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New Zealand is the world’s third-largest honey exporter by value behind China and Argentina and honey accounts for up to 80 % of New Zealand’s exports. However, it is only the 16th biggest global supplier by volume. Manuka honey from New Zealand is sold for premium prices and merchandised for its health benefits. Because of its exceptional antibacterial effect, there is a strong market demand and the price for a kilogram of manuka honey has tripled in recent years (Ministry for Primary Industries 2015). When consumers are willing to pay prices up to 200 €/kg manuka honey, the risk of misleading advertisement and intended fraud increases. This thesis aims to further characterize manuka honey and contribute to the development of a manuka honey definition. The first part deals with the antibacterial activity of manuka honey. The effect of manuka honey is mainly due to methylglyoxal, whereas the effect of non-manuka honeys is primarily caused by hydrogen peroxide. The objective is to develop a method to quantify the effect solely due to one of the respective chemical compounds and compare their effectiveness. Finally, an evaluation of the contribution of methylglyoxal and hydrogen peroxide to the inhibitory effect of honey should be given. The second part deals with chemical reactions of carbonyl compounds in honey. Because of the reactive nature of carbonyl compounds, the formation of specific glycation compounds in honey is assumed. Since the carbonyl profile of manuka honey differs remarkably from non-manuka honeys, the reaction products are expected to vary widely. Specific compounds, solely present in manuka honey, could serve as quality control parameters to ensure manuka honey authenticity. The final part deals with the metabolism of food-derived carbonyl compounds. Carbonyl compounds, like methylglyoxal or 3-deoxyglucosone are discussed to be potentially toxic to human tissues. Until now, only little is known about the impact of the diet on the physiological carbonyl-load and the metabolism of carbonyl compounds. With the help of nutrition studies and the analysis of body fluids, the question of metabolic transit of carbonyl compounds shall be addressed. The antibacterial studies showed that bacterial species are affected differently by bioactive compounds present in honey. Methylglyoxal (MGO), which is solely present in manuka honeys and hydrogen peroxide, which is formed in most conventional honeys by glucose oxidase, are strong inhibitors of the growth of S. aureus and E. coli. The strain of P. aeruginosa used for this work was not inhibited by MGO, whereas B. subtilis was not inhibited by hydrogen peroxide. To compare and quantify the effect of MGO and hydrogen peroxide, a mathematic model was created. By comparing the slopes of the linearized dose-response curves, it was found that S. aureus, E. coli and P. aeruginosa were more sensitive to hydrogen peroxide than to MGO. However, the natural amounts of MGO in honey are higher than the formation of hydrogen peroxide. Although most bacteria are more sensitive to hydrogen peroxide, MGO is the predominantly antibacterial compound in honey, because of its higher concentrations compared to hydrogen peroxide formation. The inclusion of manuka honey in α-cyclodextrin had only minor consequences on bioavailability and antibacterial activity. The commercial product “Cyclopower” (α-cyclodextrin with manuka honey) does not enhance the antibacterial activity of manuka honey on S. aureus, E. coli and P. aeruginosa. With the help of the newly developed quantitative model, it was shown that the growth of B. subtilis is synergistically inhibited with cyclopower compared to manuka honey and α-cyclodextrin alone. The study of bacterial enzymes as possible targets for bacterial inhibition with manuka honey revealed that MGO and DHA inhibited jack bean urease, which was used as a model for Helicobacter pylori urease. The concentration of MGO and DHA in manuka honey positively correlated with its urease inhibition. Conventional honeys, which lack MGO and DHA, showed significantly less urease inhibition. Based on the unique presence of MGO, manuka honey has extraordinary effects on bacteria, which might lead to further application to fight the emerging crisis of antibacterial resistance to antibiotics. Until now, there is no consistent definition for the term “genuine manuka honey”. In the present work, an approach based on unique chemical reactions in manuka honey was followed. It was shown that the exceptional high amounts of MGO induced the formation of 2-acetyl-1-pyrroline (2-AP). In manuka honey containing ≥ 250 mg/kg MGO, the 2-AP concentration was significantly increased compared to conventional honey. Moreover, honey proteins form MGO-derived reactions products, which were studied by measuring the molecular size of honey proteins. Manuka honey proteins significantly shifted to high molecular weights (HMW) with a size above 510 kDa. The amount of HMW protein in non-manuka honey was significantly lower. The cleavage of disulphide bonds led to a decrease of HMW fraction of conventional honeys but not of manuka honeys. It is hypothesized that MGO cross-linking of proteins is mainly responsible for the formation of HMW adducts in manuka honey. The formation of HMW adducts was also shown with fluorescence analysis, whereby manuka honey proteins had higher fluorescence intensities at λex=350 nm and λem=450 nm compared to non-manuka honeys. The artificial addition of MGO and its precursor dihydroxyacetone (DHA) to a non-manuka honey did not lead to an increased fluorescence up to the level of commercial manuka honeys. The MGO-derived modifications of proteins were further studied by quantifying the protein-bound Maillard reaction products N-ε-carboxyethyllysine (CEL) and methylglyoxal-derived hydroimidazolone 1 (MG-H1) after enzymatic hydrolysis of honey proteins and LC-MS/MS analysis. Their amount was significantly higher in manuka compared to conventional honeys and correlated with the MGO content of the honey. Most of the MGO-derived reactions could be simulated by spiking a conventional honey or a low MGO manuka honey with artificial MGO and subsequent storage at elevated temperatures. Higher storage temperatures were associated with a quick increase of 5-hydroxymethylfurfuraldehyd (HMF). The HMF level in honey is used as a quality parameter and should not exceed 40 mg/kg (Codex Alimentarius Commission, 2001). High concentrations of HMF may point to a fraudulent addition of MGO and the production of artificial high-price manuka honey products. Taken together, the Maillard reaction in honey could be used to control the natural origin of MGO and DHA. The consumption of honey and especially manuka honey exposes humans to high levels of dietary dicarbonyl compounds like MGO and 3-deoxyglucosone (3-DG). Both compounds were discussed as potential risk factors for the development of age-related diseases. The simulated digestion of manuka honey in the presence of gastric and ileal fluids showed that only 9 % of the initial concentration can be recovered after 8 h. The honey matrix had no stabilising effect on MGO compared to a synthetic MGO solution. In contrast to MGO, the manuka honey compound DHA was stable during all simulated digestion steps. The complexation of MGO with α-cyclodextrin did not enhance the stability of MGO. The metabolic transit of dietary MGO and 3-DG was further studied with an intervention study with healthy volunteers, who collected their daily urine. It was shown that urinary concentrations of 3-DG and its less reactive metabolites 3-deoxyfructose (3-DF) and 2-keto-3-deoxygluconic acid (3-DGA), but not MGO, were influenced by the diet. During the intervention studies, up to 40 % of dietary 3-DG was recovered as the sum of 3-DG, 3-DF and 3-DGA. The metabolite 3-DGA only played a minor role in the metabolism of dietary 3-DG in comparison to 3-DF. The concentrations 3-DF and 3-DGA in plasma only increased after the consumption of dietary 3-DG and not after the uptake of carbohydrate rich meals in general. This led to the conclusion that dietary 3-DG is effectively metabolized to 3-DF extracellularly on the apical site of the intestinal epithelium and is resorbed slowly into the circulation. In contrast, 3-DG, which is formed (intracellularly) postprandial from glucose, bypasses this metabolic system and cannot be metabolized as rapidly to 3-DF. Preliminary results obtained with saliva instead of urine as a bio fluid to study the dietary influence of dicarbonyl compounds, confirmed the hypothesis. Based on the present results, dietary dicarbonyl compounds are effectively metabolized during digestion.

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Killeen, Niall M. "Alpha-functionalisation of carbonyl compounds". Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/56184/.

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Chapter 1: Intrinsic to the methodology developed within this thesis is the exploitation of a polyheteroatom 3,3-sigmatropic rearrangement. This chapter explores the chemistry of a selection of these rearrangements in order to highlight their utility in the creation of new carbon-carbon and carbon-heteroatom bonds. Chapter 2: In this chapter the most recent advances in the alpha-functionalisation of carbonyl compounds are discussed. This review focuses mainly on organocatalyzed methodologies as these represent the forefront of current research in the field. Chapter 3: In chapter 3 the principle underlying our methodology is further described along with our results for the alpha-oxybenzoylation of cyclic, heterocyclic and acyclic ketones. Our findings for the alpha-oxybenzoylation of acetals is also described. Chapter 4: Elaboration of our family of reagents to introduce alpha-oxycarbonate and carbamate functionalities is next described with our results for a variety of reactions with cyclic and acyclic ketones. Chapter 5: Continuing expansion of our reagent family is described in chapter 5. Within this chapter our results for the alpha-oxytosylation of cyclic, acyclic and di-carbonyl compounds are presented. Chapter 6: Chapter 6 describes our attempts at synthesising a thio analogue of our reagent for the creation of a C-S bond.

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蔡雅然 e Ya-yin Choi. "The chemistry of tetraosmium carbonyl clusters". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31236765.

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Choi, Ya-yin. "The chemistry of tetraosmium carbonyl clusters /". Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19738079.

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Willasey-Wilsey, Sarah Louise. "The photochemistry of unsaturated carbonyl compounds". Thesis, King's College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309739.

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Taylor, Paul H. "Metal free-oxygenation of carbonyl compounds". Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/54244/.

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The findings to date have contributed to the development of a novel and useful class of synthetic protocol and have resulted in a greatly enhanced understanding of the fundamental workings of the &agr;-oxygenation.

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Knowles, Deborah A. "Asymmetric alpha-oxygenation of carbonyl compounds". Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/54828/.

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The a-hydroxy carbonyl group represents a significant building block in organic synthesis, which is reflected by the extensive synthetic efforts directed towards introduction of this group in a chemo- regio-, stereo-, and enantioselective manner. Traditional methods for the a-oxygenation of carbonyl compounds involve the formation and reaction of air-sensitive intermediates. This thesis describes an alternative metal-free approach to the formation of C-O bonds a- to a carbonyl group, in an asymmetric manner. Chapter l provides an overview of the literature methods for the a-oxygenation of carbonyl compounds, incorporating recent advances in this field achieved previously within the group, following discovery of 63*HC1 to affect a one-pot a-oxygenation transformation. Chapter 2 outlines our objectives and describes methods for the preparation of chiral hydroxylamine reagents based on the generic structure 108. The focus of this chapter is on establishing asymmetric transformations and their optimisation. Chapter 3 examines varying the size and nature of the 0-acyl group (R2) in order to determine its effect on the asymmetric reaction. Chapter 4 studies the influence of relative electronic effects on the asymmetric reaction, by varying the electronic properties of R1 and R2. Chapter 5 explores the role of the TV-substituent (R1) on an asymmetric a-oxyacylation transformation. Application of our methodology to other carbonyl substrates is also examined. Chapter 6 investigates an alternative method for the synthesis of chiral a-oxygenated carbonyl compounds, involving formation and reaction of chiral nitrones. In recent years methods have been developed within the group for the a-oxycarbonoylation, oxycarbamoylation and oxytosylation of carbonyl compounds. Chapter 7 investigates application of the methodology developed within this thesis to each of these transformations. Following an interesting observation, a novel procedure for the conversion of primary amines into ketones was developed, which is discussed in Chapter 8.

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Wong, Wai-yeung. "The chemistry of triosmium alkylidyne carbonyl clusters /". Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18061606.

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Reaman, Bradley Earl. "Catalytic, enantioselective oxyallylation of activated carbonyl compounds". Thesis, Montana State University, 2012. http://etd.lib.montana.edu/etd/2012/reaman/ReamanB0512.pdf.

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Stereoselective alkylations are a very useful tool in synthetic chemistry and, specifically, natural product synthesis. One such reaction, named the Tsuji-Trost allylation, is a palladium-catalyzed substitution with the overall transformation being the replacement of an allylic leaving group with a nucleophile. First observed in 1965 with the allylation of diethyl malonate [1], and in 1973 made asymmetric with the use of chiral phosphine ligands by B. M. Trost [2], the reaction has been studied and utilized extensively over the years. While there have been many examples of this reaction in the literature, few explore functionalizing the allylic electrophile. Functionalizing the "2" position of an allylic acetate or carbonate could prove to be a useful synthetic tool. Allylic acetates, chlorides and carbonates bearing a methoxymethyl group at this middle position were synthesized. beta-carbonyl ketones which work well under the Tsuji-Trost conditions were also synthesized. Phosphine ligands that provided enantiomeric excess with a variety of nucleophiles in allylic alkylations were used. Upon reaction with a palladium (0) source, the pro-nucleophiles were successfully alkylated in a stereospecific manner. The work described herein investigates modification of the Tsuji-Trost allylation in which oxy-allylation is carried out with a high yield and high degree of enantioselectivity.

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Epstein, Simon. "Asymmetric synthesis of #alpha#-amino carbonyl compounds". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393570.

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Libri sul tema "Carbonyl compounds"

Junzo, Otera, a cura di. Modern carbonyl chemistry. Weinheim: Wiley-VCH, 2000.

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Takeda, Takeshi. Modern carbonyl olefination. Weinheim: Wiley-VCH, 2004.

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Colquhoun, H. M. Carbonylation: Direct synthesis of carbonyl compounds. New York: Plenum Press, 1991.

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Hikade, David Alan. The chemistry and detection of nickel carbonyl. Ann Arbor, MI: University Microfilms International, 1991.

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Kelly, Tracy A. Studies of mono- and diphosphine metal carbonyl complexes. Dublin: University College Dublin, 1997.

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Evertz, Kaspar. Synthese und Reaktivität halogenverbrückter Carbonyleisenverbindungen. Konstanz: Hartung-Gorre, 1987.

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Boss, Kevin F. Preparation and study of some linked and unlinked substituted binuclear iron complexes. Dublin: University College Dublin, 1996.

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Gauthier-Lafaye, Jean. Méthanol et carbonylation. Saint-Fons: Rhône-Poulenc Recherches, 1986.

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Gauthier-Lafaye, Jean. Méthanol et carbonylation. Saint-Fons: Rhône-Poulenc Recherches, 1986.

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László, Kollár, a cura di. Modern carbonylation methods. Weinheim: Wiley-VCH, 2008.

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Capitoli di libri sul tema "Carbonyl compounds"

Paih, Jacques Le, Jean-Cédric Frison e Carsten Bolm. "Oxidation of Carbonyl Compounds". In Modern Oxidation Methods, 253–94. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527603689.ch9.

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Johnston, Eric V., e Jan-E. Bäckvall. "Oxidation of Carbonyl Compounds". In Modern Oxidation Methods, 353–69. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527632039.ch10.

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Liu, Xin, John E. Ellis, Eugen F. Mesaros, Anthony J. Pearson, Elke Schoffers, Janice M. Hall, Joshua H. Hoyne et al. "Transition Metal Carbonyl Compounds". In Inorganic Syntheses, 96–132. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2004. http://dx.doi.org/10.1002/0471653683.ch3.

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Carey, Francis A., e Richard J. Sundberg. "Reactions of Carbonyl Compounds". In Advanced Organic Chemistry, 439–98. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4613-9795-3_8.

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Ojima, I. "Hydrosilylation of Carbonyl Compounds". In Inorganic Reactions and Methods, 240–41. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145319.ch78.

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Dinda, Biswanath. "Photochemistry of Carbonyl Compounds". In Lecture Notes in Chemistry, 241–75. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-45934-9_8.

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Fauve, Annie. "Microbial Reduction of Carbonyl Compounds". In Biocatalysis, 179–93. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-010-9124-4_9.

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Bochmann, Manfred. "Metal carbonyl complexes". In Organometallics 1. Oxford University Press, 1994. http://dx.doi.org/10.1093/hesc/9780198557500.003.0002.

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This chapter discusses metal carbonyl complexes, one of the most important classes of organometallic compounds. Carbon monoxide (CO) binds firmly to blood haemoglobin and renders it unavailable for oxygen transport. Metal carbonyls, in particular the volatile compounds, are therefore highly toxic; nickel tetracarbonyl Ni(CO)₄ is a very potent carcinogen. The structures of metal carbonyls can be explained using the 18-electron rule. This is fulfilled if Cr, Fe, and Ni bind six, five, and four CO ligands, respectively, to give monomeric compounds. The carbonyls of Mn and Co form metal–metal bonded dimers to attain an 18 VE configuration. The chapter then looks at metal carbonyl anions, metal carbonyl hydrides, metal carbonyl halides, and metal carbonyl clusters.

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Colthup, Norman B., Lawrence H. Daly e Stephen E. Wiberley. "CARBONYL COMPOUNDS". In Introduction to Infrared and Raman Spectroscopy, 289–325. Elsevier, 1990. http://dx.doi.org/10.1016/b978-0-08-091740-5.50012-0.

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"CARBONYL COMPOUNDS". In Understanding Advanced Chemistry Through Problem Solving, 175–208. WORLD SCIENTIFIC, 2023. http://dx.doi.org/10.1142/9789811281839_0009.

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Atti di convegni sul tema "Carbonyl compounds"

Blaszczak, Zdzislaw. "Optical Kerr effect in chain carbonyl compounds". In Moscow - DL tentative, a cura di Sergei A. Akhmanov e Marina Y. Poroshina. SPIE, 1991. http://dx.doi.org/10.1117/12.57333.

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Velkova, Veronika. "DETERMINATION OF CARBONYL COMPOUNDS AT THERMAL LOADING OF WOOD". In SGEM2011 11th International Multidisciplinary Scientific GeoConference and EXPO. Stef92 Technology, 2011. http://dx.doi.org/10.5593/sgem2011/s17.112.

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Acácio, Marinice Santiago dos Santos, Jeancarlo Pereira dos Anjos e Bruna Aparecida Souza Machado. "PRESENCE OF CARBONYL COMPOUNDS IN BEERS - A BRIEF REVIEW". In VII Simpósio Internacional de Inovação e Tecnologia. São Paulo: Editora Blucher, 2021. http://dx.doi.org/10.5151/siintec2021-208823.

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Ungur, Nicon, Aurelian Gulea e Tatiana Erhan. "Synthesis and study of the same hydrazincarbothioamides as privilege pharmacophores in pharmacology". In Scientific seminar with international participation "New frontiers in natural product chemistry". Institute of Chemistry, Republic of Moldova, 2023. http://dx.doi.org/10.19261/nfnpc.2023.ab05.

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Hydrazinecarbothioamides represent a privileged class of pharmacophores in pharmacology, thanks to an impressive number of derivatives that exhibit outstanding antimicrobial, anticancer and antifungal properties [1]. The presence of electron donor atoms such as N(nitrogen) and S(sulfur) substantially widen the spectrum of use. In the framework of theoretical studies on the structure of biologically active compounds with valuable properties were highlighted following common structural elements such as substitution of a hydrogen atom from the nitrogen atom (N) with the benzene ring, the introduction of electron-donating substituents, the presence of the atom of sulfur and condensation with carbonyl compounds from the pyridine series but also with benzaldehyde derivatives [2]. At the initial stage called "ab initio", all compounds selected for synthesis were evaluated by the computational method of correspondence to Lipinski's rule [3]. Results suggest that the evaluated compounds fall within the theoretical parameters. A simulation of their interaction with an anticancer biological target such as RR (ribonucleotide reductase, the protein responsible for the synthesis of cellular DNA) was performed. Hydrazinecarbothioamides condensed with carbonyl compounds were highlighted as having a powerful anticancer potential due to their substantially lower binding energy than of free hydrazinecarbothioamides. A new series of N-(methylphenyl)hydrazinecarbothioamides were obtained starting from corresponding methylanilines. These compounds were subsequently condensed with aromatic carbonyl compounds and heterocyclics. The research of the anticancer properties was carried out in vitro, on a series of cancer cell lines: cervical adenocarcinoma (HeLa), human pancreatic adenocarcinoma (BxPC-3), muscle tissue myosarcoma (RD) and human leukemia (HL-60). The toxicity of the compounds was evaluated on the normal renal epithelial cell line (MDCK). The results of the in vitro evaluation of anticancer properties revealed that N-(2,4-dimethylphenyl)-2-(2-hydroxybenzylidene)-hydrazinecarbothioamide inhibits the proliferation of HL-60 cancer cells in proportion of 90-98%, at both concentrations of 10 μM and 0.1 μM. This compound exhibits a higher activity than DOX (doxorubicin), drug used in cancer chemotherapy.

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Pogrebnoi, Vsevolod, Natalia Sucman e Fliur Macaev. "The amides of dehydroabietic acid in synthesys of spiropyranes with the participation of carbonyl compounds". In Scientific seminar with international participation "New frontiers in natural product chemistry". Institute of Chemistry, Republic of Moldova, 2023. http://dx.doi.org/10.19261/nfnpc.2023.ab16.

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The abstract presents the synthesis of new spiropyranes from substituted 5-aminoisatin 6 in multicomponent reaction with different carbonyl compounds. It is known that spiropyranes have various activities, which depend from spatial structure and substituents [1]. From the other side, previously mentioned dehydroabietic acid 1 [2] is interesting object to study due to its molecular structure, chemical and biological properties.Initially, our strategy was to obtain the substituted isatine 6 from easily accessible isatine 3. To implement that approach, previously obtained [2] 5-nitroisatine reacted with fivefold excess of ethylene glycol [3] using 10 mol% p-toluenesulfonic acid in boiling toluene to give 4 in good yield. Next, the obtained dioxalane 4 was introduced into the reduction reaction, where the best yield was reached using the fivefold excess of tin (II) chloride [3] as reducing agent. The amidation reaction between 5-aminodioxalane 5 and chloride 2 took place in dry chloroform, using as acceptor the moderate excess Et3N [3]. During the deprotecting essay of dioxalane cycle [3] the best conditions were aqueous acetone (1:3) and 96% sulfuric acid at 350C, leading to desired isatine 6 with 75% yield. The final stage was famous three component reaction [4] between the desired isatine 4, malononitrile and carbonyl compound. The first example [3] started from pyrazoline-2-one, yielded 57% the desired compound 7. Another carbonyl compound – acetoacetic ester gave the compound 8 with 66% yield [3]. But in case of 2,4-pentanedione the reaction haven’t succeeded in different conditions selection (various solvents and long-term boiling).

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Kacikova, Danica. "CARBONYL COMPOUNDS IN SMOKE FROM BURNING OF SELECTED SYNTHETIC POLYMERS". In SGEM2011 11th International Multidisciplinary Scientific GeoConference and EXPO. Stef92 Technology, 2011. http://dx.doi.org/10.5593/sgem2011/s17.107.

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Rahaman, Md Ekhlasur, Rayhan Habib Jibon, Md Bellal Hossain, Himadri Shekhar Mondal, Abdullah Al-Mamun Bulbul, Avijit Saha e Md Mahmud Hassan. "Sensing Toxic Carbonyl Compounds in Cigarette Smoke by Photonic Crystal Fiber". In 2020 11th International Conference on Computing, Communication and Networking Technologies (ICCCNT). IEEE, 2020. http://dx.doi.org/10.1109/icccnt49239.2020.9225607.

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Al-Amood, Hanoy K., Hanan F. Al-Shamsi e Hayat H. Abbas. "Quantitative structure-activity relationships of some new beta amino-carbonyl compounds". In INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS ICNAAM 2019. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0029650.

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Dagaut, Philippe, Yuri Bedjanian, Guillaume Dayma, Fabrice Foucher, Benoît Grosselin, Manolis Romanias e Roya Shahla. "Emission of Carbonyl and Polyaromatic Hydrocarbon Pollutants From the Combustion of Liquid Fuels: Impact of Biofuel Blending". In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75136.

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The combustion of conventional fuels (Diesel and Jet A-1) with 10–20% vol. oxygenated biofuels (ethanol, 1-butanol, methyl octanoate, rapeseed oil methyl ester, diethyl carbonate, tri(propylene glycol)methyl ether, i.e., CH3(OC3H6)3OH, and 2,5-dimethylfuran) and a synthetic paraffinic kerosene was studied. The experiments were performed using an atmospheric pressure laboratory premixed flame and a four-cylinder four-stroke Diesel engine operating at 1500 rpm. Soot samples from kerosene blends were collected above a premixed flame for analysis. Polyaromatic hydrocarbons (PAHs) were extracted from the soot samples. After fractioning, they were analyzed by high-pressure liquid chromatography (HPLC) with UV and fluorescence detectors. C1 to C8 carbonyl compounds were collected at the Diesel engine exhaust on 2,4-dinitrophenylhydrazine coated cartridges (DNPH) and analyzed by HPLC with UV detection. The data indicated that blending conventional fuels with biofuels has a significant impact on the emission of both carbonyl compounds and PAHs adsorbed on soot. The global concentration of 18 PAHs (1-methyl-naphthalene, 2-methyl-naphthalene, and the 16 US priority EPA PAHs) on soot was considerably lowered using oxygenated fuels, except 2,5-dimethylfuran. Conversely, the total carbonyl emission increased by oxygenated biofuels blending. Among them, ethanol and 1-butanol were found to increase considerably the emissions of carbonyl compounds.

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Milović, Emilija, Kristina Mihajlović, Nenad Joksimović, Jelena Petronijević e Nenad Janković. "Investigation of binding mode of novel 2,4-diketo esters to BSA". In 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.463m.

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2,4-Diketo esters are well-known for their wide pharmacological activities as well as their usage in a lot of synthetic transformations. The specific structure of 2,4-diketo esters with many carbonyl groups and the presence of keto-enol tautomerism give suitable chemical properties for many applications. Therefore, an affinity for one of the binding sites of bovine serum albumin (BSA) of 2,4-diketo esters possessing good antimicrobial activity, was examined. Binding modes of compounds A and B were determined using fluorescence spectroscopy. Eosin Y was used as a marker for Sudlow’s Site I (subdomain IIA), while ibuprofen was used as a marker for Sudlow’s Site II (subdomain IIIA). Obtained values of Ka suggested that both compounds reversibly bind to BSA. Due to the values of Ka in the presence of site markers, the site II is more likely to be occupied by compound A, and compound B uses other binding modes. The presented results will help to improve the research of the mechanism of the interaction between transport proteins and similar compounds.

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Rapporti di organizzazioni sul tema "Carbonyl compounds"

Grant, T. M., e C. J. King. Irreversible adsorption of phenolic compounds by activated carbons. Office of Scientific and Technical Information (OSTI), dicembre 1988. http://dx.doi.org/10.2172/6416993.

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Hanson, Richard S. Genetics of Bacteria That Oxidize On-Carbon Compounds. Office of Scientific and Technical Information (OSTI), gennaio 2001. http://dx.doi.org/10.2172/900288.

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Lewan. PR-389-114503-R01 Leak Prevention in CO2 Pipeline Valves and Launches By Correct Seal Material Selection. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), settembre 2013. http://dx.doi.org/10.55274/r0010086.

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Pipeline Research Council International, Inc. (PRCI) required guidelines for pipeline valve stem seals in CO2 rich applications such as for enhanced oil recovery (EOR) and carbon capture and storage (CCS). In particular, guidance was needed to ascertain when standard O-rings may be used, when a switch to rapid gas decompression (RGD) resistant O-rings is recommended and when O-rings should be replaced by more robust energized lip seals and/or by more robust seal materials. The guidelines would interface with both NORSOK M 710 Rev. 3 and ISO 23936-2, and give specific details on procedures, steps and decisions that have to be taken when attempting to qualify seals for dense phase CO2 use. In order to develop these guidelines, two well established sealing compounds having proven RGD resistance were selected for study, along with two materials which were not known for their RGD resistance. RGD testing was performed on housed O-rings of each compound using 4 different gas compositions that cover an appropriate range of field conditions for CO2 applications.

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Moll, Amy Jo. Carbon doping of III-V compound semiconductors. Office of Scientific and Technical Information (OSTI), settembre 1994. http://dx.doi.org/10.2172/10196996.

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Kanner, Joseph, Mark Richards, Ron Kohen e Reed Jess. Improvement of quality and nutritional value of muscle foods. United States Department of Agriculture, dicembre 2008. http://dx.doi.org/10.32747/2008.7591735.bard.

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Food is an essential to our existence but under certain conditions it could become the origin to the accumulative health damages. Technological processes as heating, chopping, mincing, grounding, promote the lipid oxidation process in muscle tissues and meat foodstuffs. Lipid oxidation occurred rapidly in turkey muscle, intermediate in duck, and slowest in chicken during frozen storage. Depletion of tocopherol during frozen storage was more rapid in turkey and duck compared to chicken. These processes developed from lipid peroxides produce many cytotoxic compounds including malondialdehyde (MDA). The muscle tissue is further oxidized in stomach conditions producing additional cytotoxic compounds. Oxidized lipids that are formed during digestion of a meal possess the potential to promote reactions that incur vascular diseases. A grape seed extract (1% of the meat weight) and butylated hydroxytoluene (0.2% of the lipid weight) were each effective at preventing formation of lipid oxidation products for 3 hours during co-incubation with cooked turkey meat in simulated gastric fluid (SGF). Polyphenols in the human diet, as an integral part of the meal prevent the generation and absorption of cytotoxic compounds and the destruction of essential nutrients, eg. antioxidants vitamins during the meal. Polyphenols act as antioxidants in the gastrointestinal tract; they scavenge free radicals and may interact with reactive carbonyls, enzymes and proteins. These all reactions results in decreasing the absorption of reactive carbonyls and possible other cytotoxic compounds into the plasma. Consumptions of diet high in fat and red meat are contributory risk factors partly due to an increase production of cytotoxic oxidized lipid products eg. MDA. However, the simultaneously consumption of polyphenols rich foods reduce these factors. Locating the biological site of action of polyphenols in the in the gastrointestinal tract may explain the paradox between the protective effect of a highly polyphenols rich diet and the low bioavailability of these molecules in human plasma. It may also explain the "French paradox" and the beneficial effect of Mediterranean and Japanese diets, in which food products with high antioxidants content such as polyphenols are consumed during the meal.

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Blake, D. M. Photocatalytic and Chemical Oxidation of Organic Compounds in Supercritical Carbon Dioxide. Office of Scientific and Technical Information (OSTI), luglio 1999. http://dx.doi.org/10.2172/14658.

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Blake, Daniel M. Photocatalytic and Chemical Oxidation of Organic Compounds in Supercritical Carbon Dioxide. Office of Scientific and Technical Information (OSTI), dicembre 2000. http://dx.doi.org/10.2172/827240.

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Heath, Jeff. Using Stable Isotopes of Carbon to Monitor Biodegradation of Pollutant Compounds,. Fort Belvoir, VA: Defense Technical Information Center, aprile 1995. http://dx.doi.org/10.21236/ada302216.

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DePuy, C. H., e V. M. Bierbaum. Gas Phase Ion-Molecule Chemistry of Carbon, Nitrogen and Oxygen Compounds. Fort Belvoir, VA: Defense Technical Information Center, gennaio 1985. http://dx.doi.org/10.21236/ada152876.

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Sisler, Edward C., Raphael Goren e Akiva Apelbaum. Controlling Ethylene Responses in Horticultural Crops at the Receptor Level. United States Department of Agriculture, ottobre 2001. http://dx.doi.org/10.32747/2001.7580668.bard.

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Ethylene is a plant hormone that controls many plant responses, such as growth, senescence, ripening, abscission and seed germination. Recently, 1-methy- cyclopropene (1-MCP), was shown to bind to ethylene receptor for a certain period of time and prevent ethylene action. The objectives of this research were to synthesize analogues of 1-MCP and test their potency to block the ethylene receptor and inhibit ethylene action. During the course of this project, procedures for synthesis and shipment of the cyclopropene compounds were developed as well assay procedures for each compound were worked out. Thirteen new compounds were synthesized. All of them are structural analogues of 1-MCP, with substitution in the 1-position and a side chain containing 2 to 10 carbons. After preliminary studies, nine promising compounds were selected for in-depth study. The potency of the compounds to inhibit ethylene action was tested on a wide scope of systems like: climacteric fruits (banana, avocado and tomato), the triple response (etiolated peas), and leaf abscission (citrus). As the putative inhibitors are suspected to compete for the site of binding and a competitive type of inhibition could be considered, a high concentration of ethylene (300 m1.L-1) was used to induce ripening and other physiological processes. The tests were conducted under extreme conditions which hasten ripening like treatment and storage at 22 to 25oC. There were fluctuations in the responses as related to the concentrations of the inhibitors. Some required much higher concentration to exert the same effect, while some, when applied at the same concentration, blocked the receptor for a longer period of time than the others. Some fruits and other plant organs responded differently to the same inhibitor, indicating differences in characteristics and availability of the ethylene receptors in the various tissues. The potency of the putative inhibitors was found to be greatly affected by their molecular structural and size. In addition, it was found that treatment with the inhibitor should be given before the onset of ethylene action In the case of fruit, treatment should be carried out before the pre-climacteric stage. Simultaneous treatment with ethylene and the inhibitors reduced the inhibitors' effect. The relationship between ethylene and the inhibitors is of a non-competitive nature. All the fruits treated with the putative inhibitors resumed normal ripening after recovery from the inhibition. This fact is of great importance when considering the inhibitors for practical use. The advantage of using inhibitors of ethylene action over inhibitors of ethylene production lies in the ability of the inhibitors of ethylene action to protect the tissue against both endogenous and exogenous ethylene, thus providing better overall protection. Our findings indicate that 1-MCP and its structural analogues are potent inhibitors of ethylene action capable of providing good protection against endogenous and exogenous ethylene. The fact that the compounds are in a gas phase and are non-phytotoxic, odorless and effective at minute concentrations, renders them promising candidates for commercial use. However, the development of water-soluble inhibitors will expand the potential use of the inhibitors in agriculture.

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