ChemInform Abstract: Palladium Catalyzed Csp2-H Activation for Direct Aryl Hydroxylation: The Unprecedented Role of 1,4-Dioxane as a Source of Hydroxyl Radicals.

ChemInform ◽  
2015 ◽  
Vol 46 (22) ◽  
pp. no-no
Author(s):  
Kapileswar Seth ◽  
Manesh Nautiyal ◽  
Priyank Purohit ◽  
Naisargee Parikh ◽  
Asit K. Chakraborti
Keyword(s):  
Hydroxyl Radicals ◽  
Palladium Catalyzed

Palladium catalyzed Csp2–H activation for direct aryl hydroxylation: the unprecedented role of 1,4-dioxane as a source of hydroxyl radicals

2015 ◽  
Vol 51 (1) ◽  
pp. 191-194 ◽  
Author(s):  
Kapileswar Seth ◽  
Manesh Nautiyal ◽  
Priyank Purohit ◽  
Naisargee Parikh ◽  
Asit K. Chakraborti
Keyword(s):  
Hydroxyl Radicals ◽  
Palladium Catalyzed

Direct aryl hydroxylation has been achieved via palladium-catalysed Csp2–H activation using versatile directing groups through unprecedented hydroxyl transfer from 1,4-dioxane.

scholarly journals Cisplatin-induced hydroxyl radicals mediate pro-survival autophagy in human lung cancer H460 cells

2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Somruethai Sumkhemthong ◽  
Eakachai Prompetchara ◽  
Pithi Chanvorachote ◽  
Chatchai Chaotham
Keyword(s):  
Lung Cancer ◽  
Hydroxyl Radicals ◽  
Human Lung ◽  
Human Lung Cancer ◽  
Radical Scavenger ◽  
Apoptosis Resistance ◽  
Lung Cancer Patients ◽  
Human Lung Cancer Cells ◽  
H460 Cells

Abstract Background Accumulated evidence demonstrates cisplatin, a recommended chemotherapy, modulating pro-survival autophagic response that contributes to treatment failure in lung cancer patients. However, distinct mechanisms involved in cisplatin-induced autophagy in human lung cancer cells are still unclear. Results Herein, role of autophagy in cisplatin resistance was indicated by a decreased cell viability and increased apoptosis in lung cancer H460 cells pre-incubated with wortmannin, an autophagy inhibitor, prior to treatment with 50 µM cisplatin for 24 h. The elevated level of hydroxyl radicals detected via flow-cytometry corresponded to autophagic response, as evidenced by the formation of autophagosomes and autolysosomes in cisplatin-treated cells. Interestingly, apoptosis resistance, autophagosome formation, and the alteration of the autophagic markers, LC3-II/LC3-I and p62, as well as autophagy-regulating proteins Atg7 and Atg3, induced by cisplatin was abrogated by pretreatment of H460 cells with deferoxamine, a specific hydroxyl radical scavenger. The modulations in autophagic response were also indicated in the cells treated with hydroxyl radicals generated via Fenton reaction, and likewise inhibited by pretreatment with deferoxamine. Conclusions In summary, the possible role of hydroxyl radicals as a key mediator in the autophagic response to cisplatin treatment, which was firstly revealed in this study would benefit for the further development of novel therapies for lung cancer.

Elucidating the Key Role of Phosphine−Sulfonate Ligands in Palladium-Catalyzed Ethylene Polymerization: Effect of Ligand Structure on the Molecular Weight and Linearity of Polyethylene

ACS Catalysis ◽  
2016 ◽  
Vol 6 (9) ◽  
pp. 6101-6113 ◽  
Author(s):  
Ryo Nakano ◽  
Lung Wa Chung ◽  
Yumiko Watanabe ◽  
Yoshishige Okuno ◽  
Yoshikuni Okumura ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ethylene Polymerization ◽  
Ligand Structure ◽  
Palladium Catalyzed

Key Role of Equilibrium HONO Concentration over the Soil 

2021 ◽  
Author(s):  
Fengxia Bao ◽  
Hang Su ◽  
Uwe Kuhn ◽  
Yafang Cheng
Keyword(s):  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Nitrous Acid ◽  
Measurement Method ◽  
Oxidative Capacity ◽  
Sources And Sinks ◽  
Dynamic Chamber ◽  
Open Question ◽  
Actinic Radiation

<p>Nitrous acid (HONO) is an important component of the nitrogen cycle. HONO can also be rapidly photolyzed by actinic radiation to form hydroxyl radicals (OH) and exerts a primary influence on the oxidative capacity of the atmosphere. The sources and sinks of HONO, however, are not fully understood. Soil nitrite, produced via nitrification or denitrification, is an important source for the atmospheric HONO production. [HONO]*, the equilibrium gas phase HONO concentration over the soil, has been suggested as key to understanding the environmental effects of soil fluxes of HONO (Su et al., 2011). But if and how [HONO]* may exist and vary remains an open question. In this project, a measurement method using a dynamic chamber has been developed to derive [HONO]* and the atmospheric soil fluxes of HONO can accordingly be quantified. We demonstrate the existence of [HONO]* and determine its variation in the course of soil drying processes. We show that when [HONO]* is higher than the atmospheric HONO concentration, HONO will be released from soil; otherwise, HONO will be deposited on soil. This work advances the understanding of soil HONO emissions, and the evaluation of its impact on the atmospheric oxidizing capacity and the nitrogen cycling.</p>

scholarly journals Palladium-catalyzed Suzuki-Miyaura coupling of thioureas or thioamides

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Shaoyu Mai ◽  
Wendong Li ◽  
Xue Li ◽  
Yingwei Zhao ◽  
Qiuling Song
Keyword(s):  
Silver Salt ◽  
Coupling Reaction ◽  
Coupling Reactions ◽  
Mechanistic Studies ◽  
Aromatic Rings ◽  
Cross Coupling Reactions ◽  
Broad Array ◽  
Palladium Catalyzed

AbstractCross-coupling reactions involving metal carbene intermediates play an increasingly important role in C–C bond formation. Expanding the carbene precursors to a broader range of starting materials and more diverse products is an ongoing challenge in synthetic organic chemistry. Herein, we report a Suzuki-Miyaura coupling reaction of in situ-generated Pd–carbene complexes via desulfurization of thioureas or thioamides. This strategy enables the preparation of a broad array of substituted amidinium salts and unsymmetrical diaryl ketones. The reaction is readily scalable, compatible with bromo groups on aromatic rings, tolerant to moisture and air and has a broad substrate scope. Furthermore, a single crystal structure of Pd-diaminocarbene complex is obtained and proven to be the key intermediate in both catalytic and stoichiometric reactions. Preliminary mechanistic studies demonstrate the dual role of the silver salt as a desulfurating reagent assisting the elimination of sulfur and as oxidant facilitating the PdII/Pd0/PdII catalytic cycle.

The role of alkoxy radicals in the heterogeneous reaction of two structural isomers of dimethylsuccinic acid

2015 ◽  
Vol 17 (38) ◽  
pp. 25309-25321 ◽  
Author(s):  
Chiu Tung Cheng ◽  
Man Nin Chan ◽  
Kevin R. Wilson
Keyword(s):  
Molecular Weight ◽  
Hydroxyl Radicals ◽  
Heterogeneous Reaction ◽  
Methyl Groups ◽  
Structural Isomers ◽  
Alkoxy Radicals ◽  
Weight Growth ◽  
Bond Scission

The heterogeneous reaction of hydroxyl radicals with two isomers of dimethylsuccinic acid is used to explore how the location of branched methyl groups controls C–C bond scission and molecular weight growth reactions.

Palladium-Catalyzed Synthesis of Δ2-Isoxazoline from Toluene Derivatives Enabled by the Triple Role of Silver Nitrate

2015 ◽  
Vol 17 (22) ◽  
pp. 5718-5721 ◽  
Author(s):  
Chengliang Li ◽  
Hongmei Deng ◽  
Chunju Li ◽  
Xueshun Jia ◽  
Jian Li
Keyword(s):  
Silver Nitrate ◽  
Palladium Catalyzed
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