Einloggen

Thematische Bibliographien / Carbonyl compounds / Zeitschriftenartikel

Zeitschriftenartikel zum Thema „Carbonyl compounds“

Um die anderen Arten von Veröffentlichungen zu diesem Thema anzuzeigen, folgen Sie diesem Link: Carbonyl compounds.

Autor: Grafiati

Veröffentlicht am 4. Juni 2021

Zuletzt aktualisiert am 11. September 2023

Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an

Wählen Sie eine Art der Quelle aus:

Machen Sie sich mit Top-50 Zeitschriftenartikel für die Forschung zum Thema "Carbonyl compounds" bekannt.

Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.

Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.

Sehen Sie die Zeitschriftenartikel für verschiedene Spezialgebieten durch und erstellen Sie Ihre Bibliographie auf korrekte Weise.

1

Epstein, S. A., E. Tapavicza, F. Furche und S. A. Nizkorodov. „Direct photolysis of carbonyl compounds dissolved in cloud and fog droplets“. Atmospheric Chemistry and Physics Discussions 13, Nr. 4 (24.04.2013): 10905–37. http://dx.doi.org/10.5194/acpd-13-10905-2013.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

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.

2

Hu, Yue, Wei Sun und Chao Liu. „Deoxygenative Transformation of Carbonyl and Carboxyl Compounds Using gem-Diborylalkanes“. Synlett 30, Nr. 10 (21.02.2019): 1105–10. http://dx.doi.org/10.1055/s-0037-1611728.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

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

3

Epstein, S. A., E. Tapavicza, F. Furche und S. A. Nizkorodov. „Direct photolysis of carbonyl compounds dissolved in cloud and fog~droplets“. Atmospheric Chemistry and Physics 13, Nr. 18 (26.09.2013): 9461–77. http://dx.doi.org/10.5194/acp-13-9461-2013.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

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.

4

Vizer, S. A., und K. B. Yerzhanov. „Heterocycles Synthesis at Carbonylation of Acetylenic Compounds“. Eurasian Chemico-Technological Journal 5, Nr. 2 (05.04.2016): 145. http://dx.doi.org/10.18321/ectj294.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

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.

5

Hellén, H., H. Hakola, A. Reissell und T. M. Ruuskanen. „Carbonyl compounds in boreal coniferous forest air in Hyytiälä, Southern Finland“. Atmospheric Chemistry and Physics 4, Nr. 7 (08.09.2004): 1771–80. http://dx.doi.org/10.5194/acp-4-1771-2004.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

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.

6

Wang, Jinhe, Shan Chen, Xiaoguo Qiu, Wenya Niu, Ouyang Li, Chao Zhu, Xi Zhang, Xue Yang und Guiqin Zhang. „Pollution Characteristics of Atmospheric Carbonyl Compounds in a Large City of Northern China“. Journal of Chemistry 2022 (24.01.2022): 1–13. http://dx.doi.org/10.1155/2022/3292598.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

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.

7

Moldoveanu, S., W. Coleman und J. Wilkins. „Determination of Carbonyl Compounds in Exhaled Cigarette Smoke“. Beiträge zur Tabakforschung International/Contributions to Tobacco Research 22, Nr. 5 (01.06.2007): 346–57. http://dx.doi.org/10.2478/cttr-2013-0841.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

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.

8

Hellén, H., H. Hakola, A. Reissell und T. M. Ruuskanen. „Carbonyl compounds in boreal coniferous forest air in Hyytiälä, Southern Finland“. Atmospheric Chemistry and Physics Discussions 4, Nr. 3 (03.06.2004): 2991–3011. http://dx.doi.org/10.5194/acpd-4-2991-2004.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

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.

9

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

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

10

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, Nr. 5 (08.05.2022): 761. http://dx.doi.org/10.3390/atmos13050761.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

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.

11

Son, Yeongkwon, Clifford Weisel, Olivia Wackowski, Stephan Schwander, Cristine Delnevo und Qingyu Meng. „The Impact of Device Settings, Use Patterns, and Flavorings on Carbonyl Emissions from Electronic Cigarettes“. International Journal of Environmental Research and Public Health 17, Nr. 16 (05.08.2020): 5650. http://dx.doi.org/10.3390/ijerph17165650.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Health impacts of electronic cigarette (e-cigarette) vaping are associated with the harmful chemicals emitted from e-cigarettes such as carbonyls. However, the levels of various carbonyl compounds under real-world vaping conditions have been understudied. This study evaluated the levels of carbonyl compounds (e.g., formaldehyde, acetaldehyde, glyoxal, and diacetyl, etc.) under various device settings (i.e., power output), vaping topographies, and e-liquid compositions (i.e., base liquid, flavor types). The results showed that e-vapor carbonyl levels were the highest under higher power outputs. The propylene glycol (PG)-based e-liquids generated higher formaldehyde and acetaldehyde than vegetable glycerin (VG)-based e-liquids. In addition, fruit flavored e-liquids (i.e., strawberry and dragon fruit) generated higher formaldehyde emissions than mint/menthol and creamy/sweet flavored e-liquids. While single-top coils formed 3.5-fold more formaldehyde per puff than conventional cigarette smoking, bottom coils generated 10–10,000 times less formaldehyde per puff. In general, increases in puff volume and longer puff durations generated significantly higher amounts of formaldehyde. While e-cigarettes emitted much lower levels of carbonyl compounds compared to conventional cigarettes, the presence of several toxic carbonyl compounds in e-cigarette vapor may still pose potential health risks for users without smoking history, including youth. Therefore, the public health administrations need to consider the vaping conditions which generated higher carbonyls, such as higher power output with PG e-liquid, when developing e-cigarette product standards.

12

Martínez-Ferraté, Oriol, Basujit Chatterjee, Christophe Werlé und Walter Leitner. „Hydrosilylation of carbonyl and carboxyl groups catalysed by Mn(i) complexes bearing triazole ligands“. Catalysis Science & Technology 9, Nr. 22 (2019): 6370–78. http://dx.doi.org/10.1039/c9cy01738k.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

13

Liu, Xingyun, Wei Xing, Zhaoyang Xu, Xiaomin Zhang, Hui Zhou, Kezhou Cai, Baocai Xu und Conggui Chen. „Assessing Impacts of Additives on Particulate Matter and Volatile Organic Compounds Produced from the Grilling of Meat“. Foods 11, Nr. 6 (14.03.2022): 833. http://dx.doi.org/10.3390/foods11060833.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Cooking fumes are an important source of volatile organic compounds (VOCs), particulate matter (PM), and carbonyl compounds. The additive is wildly applied in grilling meat for flavor improvement. However, the effects of additives on cooking fumes emissions, such as volatile organic compounds (VOCs), particulate matter (PM), and carbonyl compounds, in meat grilling have not been studied. The impact of four additives, including white pepper, salt, garlic powder, and compound marinade, on the emission characteristics of cooking fumes from the grilling meat was investigated. The concentrations of VOCs and carbonyl compounds in the cooking fumes were analyzed by TD-GC/MS and HPLC, respectively. The PM emission characteristics (mass concentration and size distribution) were measured by DustTrak DRX aerosol monitor in real-time. Results showed that the application of white pepper, salt, garlic powder, and mixed spices could significantly reduce the total particles mass concentration (TPM) emissions during meat-grilling by 65.07%, 47.86%, 32.87%, and 56.01%, respectively. The mass concentration of PM during meat-grilling reached maximum values ranging from 350 to 390 s and gradually fell at the final stages of grilling. The total concentration of 22 representative VOCs emitted from the grilling was significantly increased in grilling meat marinated with compound additives. Aromatic hydrocarbons were the predominant VOCs species, followed by ketone compounds. During the grilling process, formaldehyde, acetaldehyde, propionaldehyde, and acetone were major carbonyl compounds. The low molecular weight carbonyl compounds (C1–C3) in cooking fumes were dominant carbonyl compounds.

14

Ortiz, Cristian, Fernando Echeverri, Sara Robledo, Daniela Lanari, Massimo Curini, Wiston Quiñones und Esteban Vargas. „Synthesis and Evaluation of Antileishmanial and Cytotoxic Activity of Benzothiopyrane Derivatives“. Molecules 25, Nr. 4 (12.02.2020): 800. http://dx.doi.org/10.3390/molecules25040800.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

In continuation of our efforts to identify promising antileishmanial agents based on the chroman scaffold, we synthesized several substituted 2H-thiochroman derivatives, including thiochromenes, thichromanones and hydrazones substituted in C-2 or C-3 with carbonyl or carboxyl groups. Thirty-two compounds were thus obtained, characterized, and evaluated against intracellular amastigotes of Leishmania (V) panamensis. Twelve compounds were active, with EC50 values lower than 40 µM, but only four compounds displayed the highest antileishmanial activity, with EC50 values below 10 µM; these all compounds possess a good Selectivity Index > 2.6. Although two active compounds were thiochromenes, a clear structure-activity relationship was not detected since each active compound has a different substitution pattern.

15

Chen, W. T., M. Shao, S. H. Lu, M. Wang, L. M. Zeng, B. Yuan und Y. Liu. „Understanding primary and secondary sources of ambient carbonyl compounds in Beijing using the PMF model“. Atmospheric Chemistry and Physics 14, Nr. 6 (26.03.2014): 3047–62. http://dx.doi.org/10.5194/acp-14-3047-2014.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Abstract. Carbonyl compounds are important intermediates in atmospheric photochemistry. To explore the relative contributions of primary and secondary carbonyl sources, carbonyls and other volatile organic compounds (VOCs) were measured at an urban site in both winter and summer in Beijing. The positive matrix factorization (PMF) model was used for source apportionment of VOCs. As VOCs undergo photochemical processes in the atmosphere, and such processes may interfere with factor identification, the relationships between the contributions of the resolved PMF factors to each non-methane hydrocarbon (NMHC) species and its kOH value were used to distinguish fresh factors and photochemically aged factors. As the result of PMF, five factors were resolved in winter, and two of them were identified as photochemically aged emissions. In summer, four factors were resolved, including one aged factor. Carbonyls abundances from aged factors were simulated by VOCs consumption and the corresponding carbonyl production yields, and the simulated abundances agreed well with the results obtained by the PMF model. The source apportionment results indicated that secondary formation was the major source of carbonyls in both winter and summer, with the respective contributions of 51.2% and 46.0%. For the three major carbonyl species, primary anthropogenic sources contributed 28.9% and 32.3% to ambient formaldehyde, 53.7% and 41.6% to acetaldehyde, 68.1% and 56.2% to acetone in winter and summer, respectively.

16

Wu, Fan, Cheng Ye und Weiqi Tong. „Nickel-Catalyzed Reductive Cross-Coupling of Oxalates Derived from α-Hydroxy Carbonyls with Vinyl Bromides“. Synthesis 54, Nr. 09 (10.02.2022): 2251–57. http://dx.doi.org/10.1055/s-0040-1719881.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

AbstractA nickel-catalyzed cross-electrophile coupling is disclosed in which a range of vinyl bromides were utilized as electrophiles with oxalates derived from α-hydroxy carbonyls as precursors to carbonyl radical coupling partners. This method is compatible with a broad range of functional groups, providing a complementary solution for the construction of β,γ-unsaturated carbonyl compounds.

17

Chen, W. T., M. Shao, S. H. Lu, M. Wang und L. M. Zeng. „Understanding primary and secondary sources of ambient carbonyl compounds in Beijing using the PMF model“. Atmospheric Chemistry and Physics Discussions 13, Nr. 6 (13.06.2013): 15749–81. http://dx.doi.org/10.5194/acpd-13-15749-2013.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Abstract. Carbonyls are important intermediates in atmospheric photochemistry. To determine the relative contributions of primary and secondary carbonyl sources in Beijing, carbonyls and other trace gases were measured at Peking University in winter and summer. The Positive Matrix Factorization (PMF) model was used for source apportionment. As volatile organic compounds (VOCs) will undergo photochemical processes in the atmosphere, and such processes may interfere with factors identification, the relationships between the contributions of the resolved PMF factors to each non-methane hydrocarbon (NMHC) species and its kOH value were used to distinguish between photochemically aged factors and fresh factors. As the result of PMF, five factors were resolved in winter, and two of them were identified as sources of photochemically aged emissions. In summer, four factors were resolved, including an aged factor. Carbonyls in the aged factors were simulated by NMHCs consumption and the corresponding carbonyl production yields, and the simulated abundances agreed well with the results obtained by PMF. The source apportionment results indicated that secondary formation was the major source of carbonyls in both seasons, with the contribution of 51.2% and 46.0%. For the three major carbonyl species, primary anthropogenic sources contributed 28.9% and 32.3% to ambient formaldehyde, 53.7% and 41.6% to acetaldehyde, 68.1% and 56.2% to acetone in winter and summer, respectively.

18

Wang, Hongli, Xuan Zhang und Zhongming Chen. „Development of DNPH/HPLC method for the measurement of carbonyl compounds in the aqueous phase: applications to laboratory simulation and field measurement“. Environmental Chemistry 6, Nr. 5 (2009): 389. http://dx.doi.org/10.1071/en09057.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Environmental context. Carbonyl compounds, a class of oxygenated organic matter, are crucial participants in atmospheric processes. Recently, studies have shown that the aqueous-phase processes of carbonyls have an important contribution to the formation of secondary organic aerosol (SOA), which is considered to have a significant impact on global climate change and human health. We developed the classical DNPH/HPLC method to characterise the aqueous-phase carbonyls, especially methacrolein, methyl vinyl ketone, glyoxal, and methylglyoxal, which are important precursors of SOA, in order to better understand the pathways of SOA formation in the atmosphere. Abstract. The DNPH/HPLC method for characterising monocarbonyls and dicarbonyls in the aqueous phase has been developed. A series of experiments have been carried out using eight atmospheric ubiquitous carbonyl compounds as model dissolved compounds in both acetonitrile and water solution to obtain the optimal derivatisation and analysis qualifications. Compared with the analysis of carbonyls dissolved in acetonitrile, the influence of acidity on the derivatisation efficiency should be carefully considered in determining carbonyls in water and the optimal acidity is pH 2.0. We find that methyl vinyl ketone (MVK) transforms to crotonaldehyde during the derivatisation reaction. This transformation can be controlled to a minor degree by increasing the mixing ratio of DNPH to MVK up to 100 : 1. This improved method has been satisfactorily applied to laboratory simulations and field measurements for better understanding the carbonyl chemistry in the atmosphere.

19

Rodigast, M., A. Mutzel, Y. Iinuma, S. Haferkorn und H. Herrmann. „Characterisation and optimisation of a method for the detection and quantification of atmospherically relevant carbonyl compounds in aqueous medium“. Atmospheric Measurement Techniques Discussions 8, Nr. 1 (23.01.2015): 857–76. http://dx.doi.org/10.5194/amtd-8-857-2015.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Abstract. Carbonyl compounds are ubiquitous in the atmosphere and either emitted primarily from anthropogenic and biogenic sources or they are produced secondarily from the oxidation of volatile organic compounds (VOC). Despite a number of studies about the quantification of carbonyl compounds a comprehensive description of optimised methods is scarce for the quantification of atmospherically relevant carbonyl compounds. Thus a method was systematically characterised and improved to quantify carbonyl compounds. Quantification with the present method can be carried out for each carbonyl compound sampled in the aqueous phase regardless of their source. The method optimisation was conducted for seven atmospherically relevant carbonyl compounds including acrolein, benzaldehyde, glyoxal, methyl glyoxal, methacrolein, methyl vinyl ketone and 2,3-butanedione. O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was used as derivatisation reagent and the formed oximes were detected by gas chromatography/mass spectrometry (GC/MS). The main advantage of the improved method presented in this study is the low detection limit in the range of 0.01 and 0.17 μmol L−1 depending on carbonyl compounds. Furthermore best results were found for extraction with dichloromethane for 30 min followed by derivatisation with PFBHA for 24 h with 0.43 mg mL−1 PFBHA at a pH value of 3. The optimised method was evaluated in the present study by the OH radical initiated oxidation of 3-methylbutanone in the aqueous phase. Methyl glyoxal and 2,3-butanedione were found to be oxidation products in the samples with a yield of 2% for methyl glyoxal and 14% for 2,3-butanedione.

20

Doussin, J. F., und A. Monod. „Structure–activity relationship for the estimation of OH-oxidation rate constants of carbonyl compounds in the aqueous phase“. Atmospheric Chemistry and Physics 13, Nr. 23 (03.12.2013): 11625–41. http://dx.doi.org/10.5194/acp-13-11625-2013.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Abstract. In the atmosphere, one important class of reactions occurs in the aqueous phase in which organic compounds are known to undergo oxidation towards a number of radicals, among which OH radicals are the most reactive oxidants. In 2008, Monod and Doussin have proposed a new structure–activity relationship (SAR) to calculate OH-oxidation rate constants in the aqueous phase. This estimation method is based on the group-additivity principle and was until now limited to alkanes, alcohols, acids, bases and related polyfunctional compounds. In this work, the initial SAR is extended to carbonyl compounds, including aldehydes, ketones, dicarbonyls, hydroxy carbonyls, acidic carbonyls, their conjugated bases, and the hydrated form of all these compounds. To do so, only five descriptors have been added and none of the previously attributed descriptors were modified. This extension leads now to a SAR which is based on a database of 102 distinct compounds for which 252 experimental kinetic rate constants have been gathered and reviewed. The efficiency of this updated SAR is such that 58% of the rate constants could be calculated within ±20% of the experimental data and 76% within ±40% (respectively 41 and 72% for the carbonyl compounds alone).

21

Li, Lu, Wenting Dai, Minxia Shen, Xinyi Niu, Tafeng Hu, Jing Duan, Junji Cao, Zhenxing Shen, Kin Fai Ho und Jianjun Li. „Molecular Characteristics, Sources, and Health Risk Assessment of Gaseous Carbonyl Compounds in Residential Indoor and Outdoor Environments in a Megacity of Northwest China“. Indoor Air 2023 (25.07.2023): 1–13. http://dx.doi.org/10.1155/2023/7769354.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Carbonyl compounds (CCs) in indoor air pose a significant threat to residents’ health and have garnered considerable attention in recent years. However, most studies have focused on low-molecular-weight carbonyl compounds (LMW-CCs) and have underestimated the impact of high-molecular-weight ones (HMW-CCs), causing a failure to comprehensively understand their effects on health. In this study, we analyzed twenty carbonyls in the indoor and outdoor air at typical residential communities in a megacity in Northwest China by using high-performance liquid chromatography (HPLC) coupled with a photodiode array detector (DAD). The total concentration of indoor carbonyls was 1.4-3.4 times that of outdoor carbonyls. In addition, the concentration of indoor carbonyls was much higher during the heating season than that during the nonheating season. Conversely, the concentration of outdoor carbonyls was higher during the nonheating season than that during the heating season. The principal component analysis (PCA) revealed that indoor carbonyl pollution was primarily influenced by building materials, cooking fume, and wooden furniture. Formaldehyde exposure in indoor environments posed a greater health risk to children than acetaldehyde exposure. HMW-CCs were the primary contributors to indoor odor pollution, which was considered a significant cause of sick building syndrome (SBS). Our findings underscore the crucial role of HMW-CCs in indoor environments in exerting adverse impacts on health.

22

Larson, G. L. „α-silyl carbonyl compounds“. Pure and Applied Chemistry 62, Nr. 10 (01.01.1990): 2021–26. http://dx.doi.org/10.1351/pac199062102021.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

23

Boechat, N., und M. Bastos. „Trifluoromethylation of Carbonyl Compounds“. Current Organic Synthesis 7, Nr. 5 (01.10.2010): 403–13. http://dx.doi.org/10.2174/157017910792246081.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

24

Chakrabarty, Debojit, Md Munkir Hossain, R. Krishna Kumar und Pradeeb Mathur. „Mixed chalcogen carbonyl compounds“. Journal of Organometallic Chemistry 410, Nr. 2 (Juni 1991): 143–48. http://dx.doi.org/10.1016/0022-328x(91)80003-3.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

25

Mathur, Pradeep, Debojit Chakrabarty und Md Munkir Hossain. „Mixed chalcogen carbonyl compounds“. Journal of Organometallic Chemistry 418, Nr. 3 (November 1991): 415–20. http://dx.doi.org/10.1016/0022-328x(91)80226-a.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

26

Mathur, Pradeep, Debojit Chakrabarty, Md Munkir Hossain und Raad S. Rashid. „Mixed chalcogen carbonyl compounds“. Journal of Organometallic Chemistry 420, Nr. 1 (November 1991): 79–86. http://dx.doi.org/10.1016/0022-328x(91)86447-x.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

27

Grimshaw, James. „ChemInform Abstract: Carbonyl Compounds“. ChemInform 32, Nr. 30 (25.05.2010): no. http://dx.doi.org/10.1002/chin.200130270.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

28

Sohail, Muhammad, Yixin Zhang, Wujun Liu, Qin Chen, Lei Wang und Zongbao K. Zhao. „Four-component α-bromo-β-phosphoalkoxylation of aromatic α,β-unsaturated carbonyl compounds“. RSC Advances 5, Nr. 22 (2015): 17014–17. http://dx.doi.org/10.1039/c4ra12417k.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Novel α-bromo-β-phosphoalkoxylated carbonyl compounds were produced in moderate to excellent yields via highly selective four-component reaction involving NBS, a cyclic ether, an organic phosphate and an aromatic α,β-unsaturated carbonyl compound.

29

Aitken, R. Alan, und Alexandra M. Z. Slawin. „Thiophene-3-carbonyl Chloride“. Molbank 2021, Nr. 3 (22.07.2021): M1254. http://dx.doi.org/10.3390/m1254.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

The X-ray structure of the title compound has been determined for the first time. It shows the ring flip disorder common among thiophene-3-carbonyl derivatives and the occurrence of this phenomenon in the structures of such compounds is discussed.

30

Rodigast, M., A. Mutzel, Y. Iinuma, S. Haferkorn und H. Herrmann. „Characterisation and optimisation of a sample preparation method for the detection and quantification of atmospherically relevant carbonyl compounds in aqueous medium“. Atmospheric Measurement Techniques 8, Nr. 6 (08.06.2015): 2409–16. http://dx.doi.org/10.5194/amt-8-2409-2015.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Abstract. Carbonyl compounds are ubiquitous in the atmosphere and either emitted primarily from anthropogenic and biogenic sources or they are produced secondarily from the oxidation of volatile organic compounds. Despite a number of studies about the quantification of carbonyl compounds a comprehensive description of optimised methods is scarce for the quantification of atmospherically relevant carbonyl compounds. The method optimisation was conducted for seven atmospherically relevant carbonyl compounds including acrolein, benzaldehyde, glyoxal, methyl glyoxal, methacrolein, methyl vinyl ketone and 2,3-butanedione. O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was used as derivatisation reagent and the formed oximes were detected by gas chromatography/mass spectrometry (GC/MS). With the present method quantification can be carried out for each carbonyl compound originating from fog, cloud and rain or sampled from the gas- and particle phase in water. Detection limits between 0.01 and 0.17 μmol L−1 were found, depending on carbonyl compounds. Furthermore, best results were found for the derivatisation with a PFBHA concentration of 0.43 mg mL−1 for 24 h followed by a subsequent extraction with dichloromethane for 30 min at pH = 1. The optimised method was evaluated in the present study by the OH radical initiated oxidation of 3-methylbutanone in the aqueous phase. Methyl glyoxal and 2,3-butanedione were found to be oxidation products in the samples with a yield of 2% for methyl glyoxal and 14% for 2,3-butanedione after a reaction time of 5 h.

31

Miyata, Toshio, Satoshi Sugiyama, Akira Saito und Kiyoshi Kurokawa. „Reactive carbonyl compounds related uremic toxicity ("carbonyl stress")“. Kidney International 59, s78 (Februar 2001): 25–31. http://dx.doi.org/10.1046/j.1523-1755.2001.07833.x.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

32

Miyata, Toshio, Satoshi Sugiyama, Akira Saito und Kiyoshi Kurokawa. „Reactive carbonyl compounds related uremic toxicity (“carbonyl stress”)“. Kidney International 59 (Februar 2001): S25—S31. http://dx.doi.org/10.1046/j.1523-1755.2001.59780025.x.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

33

Li, Jian, Liu Shui Yan, Chun Juan Xie und Ling Na Li. „Diurnal Variations and Personal Exposures of Carbonyl Compounds in Different Types of Malls in Nanchang“. Advanced Materials Research 726-731 (August 2013): 757–60. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.757.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Diurnal variations and personal exposure of carbonyl compounds were investigated in four types of large shopping malls (including department store, supermarket, bookstore and furniture store) in urban district of Nanchang, China. The diurnal measurements both in the summer and winter showed that the concentrations of carbonyls exhibited a higher peak at the morning hour and a lower peak at the evening hour except for acetaldehyde, which obviously peaked at the afternoon hour in winter. The indoor concentrations of LMW carbonyl compounds were found higher than their outdoor counterparts with only a few exceptions. For some high molecular weight (HMW) carbonyls (C5) especially for benzaldehyde and p-Tolualdehyde which might have stronger outdoor source (e.g. vehicle exhaust), resulting in the Indoor/Outdoor ratios below 1. The personal exposures showed that large shopping malls in Nanchang were important microenvironment for exposure to formaldehyde and acetaldehyde.

34

Duong, Huy Huu, Thu Huong Minh Dang und Hien Thi To. „Partition of the carbonyl compounds between the indoor and outdoor air at residental areas in District 5, Ho Chi Minh City“. Science and Technology Development Journal 19, Nr. 2 (30.06.2016): 94–106. http://dx.doi.org/10.32508/stdj.v19i2.807.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Indoor air pollution, especially for the air toxic compounds such as carbonyls, is the most common issue in large cities. Indoor and outdoor air samples were simultaneously collected at six homes to estimate the pollution levels of carbonyl compounds at some points in the residential area, Ho Chi Minh City. The gaseous carbonyls were measured in the period of August and September, 2011 corresponding to the rainy season. The results showed that formaldehyde, acetaldehyde and acetone were the most abundant carbonyls in both indoor and outdoor air, accounted 80 % of the interested compounds, followed by propionaldehyde and benzaldehyde. In the outdoor air, the mean concentrations of formaldehyde, acetaldehyde and acetone were 15.21±6.42, 13.77±7.63, 12.11±11.72 μg.m-3, respectively. Meanwhile, the indoor concentrations were 25.45±19.49, 26.21±13.03 and 22.12±18.08 μg.m-3 for formaldehyde, acetaldehyde and acetone, respectively. Formaldehyde/acetaldehyde and acetaldehyde/ propionaldehyde ratios were 2.23±1.41 and 6.09±5.00, respestively, indicating that main sources of outdoor carbonyls came from the anthropogenic source. The mean carbonyl concentrations of the present study compared with those of other countries showed that indoor carbonyls were similar to other studies, but outdoor carbonyls were much higher. In addition, most of the indoor/outdoor ratios were slightly higher than 1 and levels of benzaldehyde and tolualdehyde were a little high in the indoor air. These results indicated that the indoor carbonyls were strongly affected by the outdoor air infiltration.

35

Blay, Gonzalo, José Pedro und Amparo Sanz-Marco. „Conjugate Alkynylation of Electrophilic Double Bonds. From Regioselectivity to Enantioselectivity“. Synthesis 50, Nr. 17 (27.07.2018): 3281–306. http://dx.doi.org/10.1055/s-0037-1610182.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

This review surveys the historical efforts addressed toward the development of the conjugate alkynylation reaction. The regio- and enantioselective conjugate alkynylation of electron-deficient double bonds, most commonly unsaturated carbonyl compounds, has been an elusive reaction for a long time. Intensive research during the last decades has resulted in the identification of a number of effective reagents and catalysts to perform this reaction. Non-stereoselective conjugate alkynylation of unsaturated carbonyl compounds was first achieved by using preformed alkynyl organometallics and later with terminal alkynes under catalytic conditions. These methods paved the way for the development of enantioselective procedures. After initial methods requiring stoichiometric amounts of chiral material, the findings by Corey on Ni-catalyzed addition of alkynylalanes and, particularly, by Carreira on Cu-catalyzed addition of terminal alkynes boosted the research on the development other asymmetric procedures catalyzed by Cu, Zn, Rh, Co, Ru and Pd complexes. The alkynylation of electrophilic alkenes conjugated with groups other than carbonyl and the alkynylation of extended conjugated systems are also discussed in the last part of this review.1 Introduction2 Non-Stereoselective Conjugate Alkynylation of α,β-Unsaturated Carbonyl Compounds3 Enantioselective Conjugate Alkynylation of α,β-Unsaturated Carbonyl Compounds4 Non-Stereoselective and Enantioselective Alkynylation of Other Electrophilic Alkenes5 γ-Alkynylation of α,β-Unsaturated Amides and δ-Alkynylation of Electrophilic Dienes6 Alternative Enantioselective Procedures7 Conclusion and Outlook

36

Nurbekova, Z. „Toxicity of reactive carbonyl compounds to plants“. BULLETIN of the L.N. Gumilyov Eurasian National University. BIOSCIENCE Series 136, Nr. 3 (2021): 86–92. http://dx.doi.org/10.32523/2616-7034-2021-136-3-86-92.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

In plants, environmental stresses result in oxidative stress, lipid peroxidation and the generation of reactive carbonyl aldehydes. Reactive carbonyl aldehydes are downstream products of reactive oxygen species which can be described as critical cell-damaging agents in plants under various environmental stresses. In this paper toxicity of reactive carbonyl aldehydes and its generation under stress conditions are discussed. Moreover, involvement of reactive carbonyl aldehydes in stress- induced damage to plants is demonstrated. Toxic effect of reactive aldehydes such as acrolein, malondialdehyde and crotonaldehyde in plants under different stresses and their high electrophilicity is also discussed. Increases in malondialdehyde was demonstrated in UV-C stressed plants as the result of carbonyl modified proteins. A malondialdehyde is one of the widely shown aldehyde, which can be demonstrated as an indicator of reactive oxygen species. Malondialdehyde isomerized to 3-hydroxyacrolein whereas it can be described as a dialdehyde. The article considers detrimental actions of reactive carbonyl aldehydes and their chemical properties as well as detoxification of reactive carbonyl aldehydes by multiple enzymes such as aldehyde dehydrogenase, aldehyde reductase, aldo-keto reductase and 2-alkenal reductase.

37

Wang, Zhiqi, Sai Li, Yu Cao, Xuefei Tian, Rong Zeng, Duan-Fang Liao und Deliang Cao. „Oxidative Stress and Carbonyl Lesions in Ulcerative Colitis and Associated Colorectal Cancer“. Oxidative Medicine and Cellular Longevity 2016 (2016): 1–15. http://dx.doi.org/10.1155/2016/9875298.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Oxidative stress has long been known as a pathogenic factor of ulcerative colitis (UC) and colitis-associated colorectal cancer (CAC), but the effects of secondary carbonyl lesions receive less emphasis. In inflammatory conditions, reactive oxygen species (ROS), such as superoxide anion free radical (O2∙-), hydrogen peroxide (H2O2), and hydroxyl radical (HO∙), are produced at high levels and accumulated to cause oxidative stress (OS). In oxidative status, accumulated ROS can cause protein dysfunction and DNA damage, leading to gene mutations and cell death. Accumulated ROS could also act as chemical messengers to activate signaling pathways, such as NF-κB and p38 MAPK, to affect cell proliferation, differentiation, and apoptosis. More importantly, electrophilic carbonyl compounds produced by lipid peroxidation may function as secondary pathogenic factors, causing further protein and membrane lesions. This may in turn exaggerate oxidative stress, forming a vicious cycle. Electrophilic carbonyls could also cause DNA mutations and breaks, driving malignant progression of UC. The secondary lesions caused by carbonyl compounds may be exceptionally important in the case of host carbonyl defensive system deficit, such as aldo-keto reductase 1B10 deficiency. This review article updates the current understanding of oxidative stress and carbonyl lesions in the development and progression of UC and CAC.

38

Alwan, Shaker M., Shayma L. Abdulhadi und Amera Abbas. „Synthesis of Levofloxacin Derivatives with some Amines and their Complexes with Copper(II) Salts and Evaluation of their Biological Activity“. International Journal of Drug Delivery Technology 10, Nr. 03 (25.09.2020): 408–13. http://dx.doi.org/10.25258/ijddt.10.3.18.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Levofloxacin belongs to the fluoroquinolone family; it is a potent broad-spectrum bactericidal agent. The pharmacophore required for significant antibacterial activity is the C-3 carboxylic acid group and the 4-pyridine ring with the C-4 carbonyl group, into which binding to the DNA bases occur. In this work, we tried to show that by masking the carboxyl group through amide formation using certain amines to form levofloxacin carboxamides, an interesting activity is kept. Levofloxacin carboxamides on the C-3 group were prepared, followed by the formation of their copper complexes. The target compounds were characterized by FT-IR, elemental analysis. The antimicrobial activity of the target compounds was evaluated and showed satisfactory results compared with levofloxacin. This has indicated that the presence of the carbonyl of C-3 carboxyl moiety is not essential, as levofloxacin carboxamides showed interesting copper complexes indicating that they retain the activity of levofloxacin, since its activity depends on binding to DNA gyrase via magnesium binding.

39

Guiheneuf, Georges, José-Luis M. Abboud und Widded Bouab. „Effets de solvant sur les complexes par transfert de charge iode – composés thiocarbonylés“. Canadian Journal of Chemistry 65, Nr. 9 (01.09.1987): 2106–8. http://dx.doi.org/10.1139/v87-349.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

The effects of solvents on different iodine – thiocarbonyl base charge-transfer complexes of variable stability have been examined and these are compared with the effects of solvents of the iodine – carbonyl compound complexes. There is an inversion of the effect of those solvents that can form hydrogen bonds on going from one series to the other, which is attributed to the fact that the carbonyl compounds are hard bases while the thiocarbonyl compounds are soft bases. [Journal translation]

40

Shlian, Daniel G., Erika Amemiya und Gerard Parkin. „Synthesis of bis(2-pyridylthio)methyl zinc hydride and catalytic hydrosilylation and hydroboration of CO₂“. Chemical Communications 58, Nr. 26 (2022): 4188–91. http://dx.doi.org/10.1039/d1cc06963b.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

41

Nicolae, Anca, Daniela Gavriliu und Ovidiu Maior. „PHENOXATHIIN CHEMISTRY. NEW CARBONYL COMPOUNDS AND DERIVATIVES“. SOUTHERN BRAZILIAN JOURNAL OF CHEMISTRY 6, Nr. 7 (20.12.1998): 47–57. http://dx.doi.org/10.48141/sbjchem.v6.n7.1998.47_1998_2.pdf.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Starting with 2-acetylphenoxathiin , 2-ω-bromoacetylphenoxathiinyl-10, 10-dioxide 2 was obtained. By means of the Kornblum reaction the corresponding glyoxal 4 was synthesized. From compound 2, the aminothiazole 3 and the 1,4-diketone 7 were also obtained. By the reaction of 2-ω-bromoacetylphenoxathiin 8 and sodium acetylacetonate "one-pot" synthesis of 1,4-diketone 9 was performed. Compound 9 was converted to pyrrolophenoxathiin 11 and 1,4-diketone 7. Starting with the brominated derivative 8 the aminoketones 12 and 13 were obtained. The new compounds were characterized by spectral methods CH-and 13C-NMR, IR, MS).

42

Then, Li Yee, C. S. Chidan Kumar, Huey Chong Kwong, Yip-Foo Win, Siau Hui Mah, Ching Kheng Quah, S. Naveen und Ismail Warad. „Two closely related 2-(benzofuran-2-yl)-2-oxoethyl benzoates: structural differences and C—H...O hydrogen-bonded supramolecular assemblies“. Acta Crystallographica Section E Crystallographic Communications 73, Nr. 7 (30.06.2017): 1087–91. http://dx.doi.org/10.1107/s2056989017009422.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

The compounds 2-(1-benzofuran-2-yl)-2-oxoethyl 2-nitrobenzoate, C17H11NO6(I), and 2-(1-benzofuran-2-yl)-2-oxoethyl 2-aminobenzoate, C17H13NO4(II), were synthesized under mild conditions. Their molecular structures were characterized by both spectroscopic and single-crystal X-ray diffraction analysis. The molecular conformations of both title compounds are generally similar. However, differentortho-substituted moieties at the phenyl ring of the two compounds cause deviations in the torsion angles between the carbonyl group and the attached phenyl ring. In compound (I), theortho-nitrophenyl ring is twisted away from the adjacent carbonyl group whereas in compound (II), theortho-aminophenyl ring is almost co-planar with the carbonyl group. In the crystal of compound (I), two C—H...O hydrogen bonds link the molecules into chains propagating along thec-axis direction and the chains are interdigitated, forming sheets parallel to [20-1]. Conversely, pairs of N—H...O hydrogen bonds in compound (II) link inversion-related molecules into dimers, which are further extended by C—H...O hydrogen bonds into dimer chains. These chains are interconnected by π–π interactions involving the furan rings, forming sheets parallel to theacplane.

43

Plackal George, Blassan, Parimelazhagan Thangaraj, Cheruthazhakkatt Sulaiman, Shanmughavel Piramanayagam und Sathish Kumar Ramaswamy. „Bioassay Directed Isolation and Biological Evaluation of Compounds Isolated fromRubus fairholmianusGard.“ BioMed Research International 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/204340.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Thein vitroandin silicoanalysis ofRubus fairholmianusacetone extract for antioxidant, antiproliferative, and anti-inflammatory activity led to the isolation of six compounds. Amongst all the six isolated compounds tested, 1-(2-hydroxyphenyl)-4-methylpentan-1-one (compound1) and 2-[(3-methylbutoxy) carbonyl] benzoic acid (compound2) were found to be more active in inhibiting BRCA and COX target proteins, which also showed the better results for DPPH and ABTS radical scavenging assays. The promising results of this investigation emphasize the importance of usingR. fairholmianusin the treatment of radical generated disorders mainly cancer and other inflammatory diseases.

44

Reinfandt, Niklas, und Peter W. Roesky. „Reactivity of a Sterical Flexible Pentabenzylcyclopentadienyl Samarocene“. Inorganics 10, Nr. 2 (18.02.2022): 25. http://dx.doi.org/10.3390/inorganics10020025.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

Reactivity studies of the classical divalent lanthanide compound [CpBz52Sm] (CpBz5 = pentabenzylcyclopentadienyl-anion) towards diphenyl dichalcogenides and d-element carbonyl complexes led to remarkable results. In the compounds obtained, a different number of Sm-C(phenyl) interactions and differently oriented benzyl groups were observed, suggesting—despite the preference of these interactions in [CpBz52Sm] described in previous studies—a flexible orientation of the benzyl groups and thus a variable steric shielding of the metal center by the ligand. The obtained compounds are either present as monometallic complexes (reduction of the dichalcogenides) or tetrametallic bridged compounds in the case of the d/f-element carbonyl complexes.

45

He, Zhen, Xin Zhang, Yunfeng Li, Xuefen Zhong, Hong Li, Rui Gao und Jinjuan Li. „Characterizing carbonyl compounds and their sources in Fuzhou ambient air, southeast of China“. PeerJ 8 (05.11.2020): e10227. http://dx.doi.org/10.7717/peerj.10227.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Annotation:

In recent years, ozone (O3) concentrations in the southeastern coastal areas of China have shown a gradual upward trend. As precursors and intermediates in the formation of O3, carbonyl compounds play key roles in the atmospheric photochemical oxidation cycle. To explore the main pollution characteristics of carbonyl compounds in a typical coastal city in southeast China, ambient samples were collected in Fuzhou (the provincial capital of Fujian province, located on the southeast coast of China) and analyzed using high-performance liquid chromatography with ultraviolet detection. The study was continuously carried out at an urban site (Jinjishan) and a suburban site (Gushan) in Fuzhou from May 8 to 20, 2018. The total concentration of 16 carbonyl compounds at the urban site was 15.45 ± 11.18 ppbv, and the total concentration at the suburban site was 17.57 ± 12.77 ppbv. Formaldehyde (HCHO), acetaldehyde, and acetone were the main species detected in the samples, and acetone had the highest concentration among the species detected. The suburban site had a higher formaldehyde/acetaldehyde ratio and lower acetaldehyde/propionaldehyde ratio than the urban site, implying that biogenic sources potentially contributed to the carbonyl compound concentrations at the suburban site. The results of an observation-based model showed that anthropogenic hydrocarbons promoted HCHO production on May 17 at the urban site. Compared to biogenic emissions, anthropogenic activity is a more important source of carbonyl compounds.

46

Murtinho, Dina, und Maria Serra. „Organocatalysed Cyanations of Carbonyl Compounds“. Current Organocatalysis 1, Nr. 2 (28.10.2014): 87–106. http://dx.doi.org/10.2174/2213337201666140521180149.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

47

Dey, Shuchismita. „Nulceophilic Displacements at Carbonyl Compounds“. Science Journal of Chemistry 3, Nr. 3 (2015): 57. http://dx.doi.org/10.11648/j.sjc.20150303.14.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

48

Talybov, G. M. „Epoxidation of unsaturated carbonyl compounds“. Russian Journal of Organic Chemistry 53, Nr. 11 (November 2017): 1742–45. http://dx.doi.org/10.1134/s1070428017110239.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

49

Comasseto, João V., Wai L. Lo und Nicola Petragnani. „Carbonyl transposition on organoselenium compounds“. Tetrahedron 53, Nr. 22 (Juni 1997): 7445–60. http://dx.doi.org/10.1016/s0040-4020(97)00454-7.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

50

Ramachandran, P. Veeraraghavan, M. Venkat Ram Reddy, Michael T. Rudd und Javier Read de Alaniz. „Vinylalumination of fluoro-carbonyl compounds“. Tetrahedron Letters 39, Nr. 48 (November 1998): 8791–94. http://dx.doi.org/10.1016/s0040-4039(98)01974-1.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen