scholarly journals Copper-Mediated Nitrosation: 2-Nitrosophenolato Complexes and Their Use in the Synthesis of Heterocycles

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4154 ◽  
Author(s):  
Alexander J. Nicholls ◽  
Andrei S. Batsanov ◽  
Ian R. Baxendale
Keyword(s):  
High Reactivity ◽  
Substitution Pattern ◽  
Decomposition Products ◽  
Novel Structure ◽  
Simple Protocol ◽  
Polymer Supported

A simple protocol yielding ortho-substituted nitrosophenols from phenols is demonstrated, in the form of copper(II) bis(nitrosophenolato) complexes. The developed methodology was applied to a range of substrates, confirming the role of the copper in both the formation and protection of the challenging 1, 2-substitution pattern. Using polymer supported thiourea, the Cu could be stripped from the complexes and thus enabled the isolation or identification of the uncoordinated ligands and their decomposition products, in yields generally low in line with the intrinsic high reactivity of 2-nitrosophenols. The product complexes are useful intermediates as demonstrated in revisiting a formal [4 + 2] cycloaddition with dimethylacetylene dicarboxylate to synthesise bicyclic products in variable yields, revealing the product has a novel structure different from those previously reported in the literature.

A first-principles study of the atomic layer deposition of ZnO on carboxyl functionalized carbon nanotubes: the role of water molecules

2021 ◽  
Vol 23 (5) ◽  
pp. 3467-3478
Author(s):  
J. I. Paez-Ornelas ◽  
H. N. Fernández-Escamilla ◽  
H. A. Borbón-Nuñez ◽  
H. Tiznado ◽  
Noboru Takeuchi ◽  
...  
Keyword(s):  
First Principles ◽  
Ligand Exchange ◽  
Functional Group ◽  
Atomic Layer ◽  
High Reactivity ◽  
Water Molecules ◽  
Exchange Reactions ◽  
Layer Deposition ◽  
The Right

Atomic description of ALD in systems that combine large surface area and high reactivity is key for selecting the right functional group to enhance the ligand-exchange reactions.

High Reactivity of the ZnO(0001) Polar Surface: The Role of Oxygen Adatoms

2017 ◽  
Vol 121 (29) ◽  
pp. 15711-15718 ◽  
Author(s):  
Yang Liu ◽  
Wangping Xu ◽  
Yueyue Shan ◽  
Hu Xu
Keyword(s):  
High Reactivity ◽  
Polar Surface ◽  
Oxygen Adatoms

The Influence of Oxygen-Rich Inclusions on the Nature of Austenite Decomposition Products of Weld Metal Deposits

1983 ◽  
Vol 21 ◽  
Author(s):  
M. Ferrante ◽  
K. Akune
Keyword(s):  
Weld Metal ◽  
Catalytic Effect ◽  
Thermal Contraction ◽  
Austenite Decomposition ◽  
Decomposition Products ◽  
The Matrix

ABSTRACTRecent studies carried out on weld metal have called attention to the role of oxygen-rich inclusions on austenite decomposition. This investigation describes some evidences of the catalytic effect of dislocations upon the γ → α transformation. These defects are generated at the matrix inclusion interface and its presence has been ascertained by TEM. Estimates of the stresses arising from differences in thermal contraction between inclusion and matrix on cooling confirm microstructural observations.

scholarly journals Characterization of the endoplasmic reticulum–resident peroxidases GPx7 and GPx8 shows the higher oxidative activity of GPx7 and its linkage to oxidative protein folding

2020 ◽  
Vol 295 (36) ◽  
pp. 12772-12785 ◽  
Author(s):  
Shingo Kanemura ◽  
Elza Firdiani Sofia ◽  
Naoya Hirai ◽  
Masaki Okumura ◽  
Hiroshi Kadokura ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Folding ◽  
Physiological Role ◽  
High Reactivity ◽  
Oxidation Activity ◽  
Formation Pathway ◽  
Oxidative Protein Folding ◽  
Redox Active ◽  
Protein Disulfide

Oxidative protein folding occurs primarily in the mammalian endoplasmic reticulum, enabled by a diverse network comprising more than 20 members of the protein disulfide isomerase (PDI) family and more than five PDI oxidases. Although the canonical disulfide bond formation pathway involving Ero1α and PDI has been well-studied so far, the physiological roles of the newly identified PDI oxidases, glutathione peroxidase-7 (GPx7) and -8 (GPx8), are only poorly understood. We here demonstrated that human GPx7 has much higher reactivity with H2O2 and hence greater PDI oxidation activity than human GPx8. The high reactivity of GPx7 is due to the presence of a catalytic tetrad at the redox-active site, which stabilizes the sulfenylated species generated upon the reaction with H2O2. Although it was previously postulated that GPx7 catalysis involved a highly reactive peroxidatic cysteine that can be sulfenylated by H2O2, we revealed that a resolving cysteine instead regulates the PDI oxidation activity of GPx7. We also determined that GPx7 formed complexes preferentially with PDI and P5 in H2O2-treated cells. Altogether, these results suggest that human GPx7 functions as an H2O2-dependent PDI oxidase in cells, whereas PDI oxidation may not be the central physiological role of human GPx8.

scholarly journals The role and effects of glucosinolates of Brassica species – a review

2011 ◽  
Vol 48 (No. 4) ◽  
pp. 175-180 ◽  
Author(s):  
H. Zukalová ◽  
J. Vašák
Keyword(s):  
Amino Acids ◽  
Brassica Species ◽  
Development Stage ◽  
Decomposition Products ◽  
Group Iii ◽  
Indole Glucosinolates ◽  
Group I ◽  
Carcinogenic Effects ◽  
In The Beginning

  Glucosinolates are the substituted esters of thio amino acids and their synthesis is based on the corresponding amino acids. Methionine and cysteine are the natural donors in the case of the Brassica plants and L-tryptophane in the indole glucosinolates, respectively. In Brassica genus, alkenyl glucosinolates are mostly present and their content and composition differ as far as the development stage and the part of the plant are concerned. The indole glucosinolates are present in a minority level. Their role of sulphur supply is questioned by their very low content between 2% in the beginning of vegetation and 0.1% in its end. Glucosinolates are discussed mostly from the aspect of their anti-nutrition, anti-microbial, anti-fungicidal, and anti-bacterial effects and as being natural bio-fumigants. Their decomposition products have the mentioned properties. The products originate by prepared passive protection by the two-component system. From the aspect of these properties, it is useful to divide them into the following three groups according to the characters of their decomposition products. The first group (I.), whose hydrolysis in the neutral and alkaline environment creates iso-thio-cyanates. These bioactive compounds form the natural protection of the plant with bio-fumigatory effects particularly. Their anti-nutritive effects can be compensated by iodine, contrary to the second group (II.). This group is created by hydroxy-glucosinolates, whose decomposition products – iso-thio-cyanates – are not stable and they cycle while producing substituted 2-oxazolidinethione (goitrine – VTO). These glucosinolates represent a serious problem in feed industry since the VTO has a strong goitrogenic property. The third group (III.) – glucosinolates containing the indole group or the benzene ring (Sinalbin), create thio-cyanates during their hydrolysis. The role of indole glucosinolates has not been completely clarified so far. Their anti-carcinogenic effects are studied and they fulfil the role of an active protection.

The role of the substitution pattern on the catalytic activity of chiral bridgehead norbornane-derived β-amino alcohols

2002 ◽  
Vol 13 (14) ◽  
pp. 1457-1460 ◽  
Author(s):  
Antonio Garcı́a Martı́nez ◽  
Enrique Teso Vilar ◽  
Amelia Garcı́a Fraile ◽  
Santiago de la Moya Cerero ◽  
Paloma Martı́nez-Ruiz
Keyword(s):  
Catalytic Activity ◽  
Amino Alcohols ◽  
Substitution Pattern

Crosslinking Chlorosulfonated Polyethylenes

1963 ◽  
Vol 36 (4) ◽  
pp. 963-974 ◽  
Author(s):  
J. T. Maynard ◽  
P. R. Johnson
Keyword(s):  
Free Radical ◽  
Sulfonyl Chloride ◽  
High Reactivity ◽  
Good Resistance ◽  
Chlorosulfonated Polyethylene ◽  
Ionic Salt ◽  
Ionic Bonds ◽  
Resistance To Heat ◽  
Curing Systems

Abstract The broadening practical use of chlorosulfonated polyethylene elastomers for applications where good resistance to heat, oil, light, oxygen, and ozone is needed has been accelerated by the development of several chemically distinct curing systems. Optimum use of these saturated elastomers requires a knowledge of the chemistry of these curing reactions and the effect of the resulting crosslink structures on vulcanizate properties. The high reactivity of the sulfonyl chloride crosslinking sites allows wide latitude in choice of curing chemistry, and crosslink type can be controlled to give a preponderance of ionic salt bonds or to give a mixture of covalent and ionic bonds. The role of water, alcohols, sulfur accelerators and free radical stabilizers in the various practical curing systems is discussed. The development of wholly organic curing systems for chlorosulfonated polyethylenes is reviewed. The properties of vulcanizates of chlorosulfonated polyethylenes are also significantly controlled by the base polyethylene, by chlorine content, and by chlorine distribution. The effects of these variables on vulcanizate properties is briefly reviewed.

scholarly journals Probing the protein–nanoparticle interface: the role of aromatic substitution pattern on affinity

2014 ◽  
Vol 27 (1-2) ◽  
pp. 123-126 ◽  
Author(s):  
Zeynep Ekmekci ◽  
Krishnendu Saha ◽  
Daniel F. Moyano ◽  
Gulen Yesilbag Tonga ◽  
Hao Wang ◽  
...  
Keyword(s):  
Aromatic Substitution ◽  
Substitution Pattern
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