OH-Initiated Photooxidations of 1-Pentene and 2-Methyl-2-propen-1-ol: Mechanism and Yields of the Primary Carbonyl Products

ChemPhysChem ◽  
2014 ◽  
Vol 15 (17) ◽  
pp. 3848-3854 ◽  
Author(s):  
Silvina A. Peirone ◽  
Pablo M. Cometto ◽  
Silvia I. Lane
Keyword(s):  
Carbonyl Products

scholarly journals Biomimetic Cu/Nitroxyl Catalyst Systems for Selective Alcohol Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 395 ◽  
Author(s):  
Lindie Marais ◽  
Andrew John Swarts
Keyword(s):  
Active Sites ◽  
Alcohol Oxidation ◽  
Galactose Oxidase ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Mechanistic Pathway ◽  
Oxidation Of Alcohols ◽  
Catalyst Systems ◽  
Carbonyl Products

The oxidation of alcohols to the corresponding carbonyl products is an important organic transformation and the products are used in a variety of applications. The development of catalytic methods for selective alcohol oxidation have garnered significant attention in an attempt to find a more sustainable method without any limitations. Copper, in combination with 2,2,6,6-tetramethyl-1-piperidine N-oxyl (TEMPO) and supported by organic ligands, have emerged as the most effective catalysts for selective alcohol oxidation and these catalyst systems are frequently compared to galactose oxidase (GOase). The efficiency of GOase has led to extensive research to mimic the active sites of these enzymes, leading to a variety of Cu/TEMPO· catalyst systems being reported over the years. The mechanistic pathway by which Cu/TEMPO· catalyst systems operate has been investigated by several research groups, which led to partially contradicting mechanistic description. Due to the disadvantages and limitations of employing TEMPO· as co-catalyst, alternative nitroxyl radicals or in situ formed radicals, as co-catalysts, have been successfully evaluated in alcohol oxidation. Herein we discuss the development and mechanistic elucidation of Cu/TEMPO· catalyst systems as biomimetic alcohol oxidation catalysts.

scholarly journals Detection of short-chain carbonyl products of lipid peroxidation from malaria-parasite (Plasmodium vinckei)-infected red blood cells exposed to oxidative stress

1988 ◽  
Vol 249 (1) ◽  
pp. 63-68 ◽  
Author(s):  
G D Buffinton ◽  
N H Hunt ◽  
W B Cowden ◽  
I A Clark
Keyword(s):  
Lipid Peroxidation ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Malaria Parasite ◽  
Radical Scavenger ◽  
Parasite Plasmodium ◽  
Infected Rbcs ◽  
Carbonyl Products ◽  
Plasmodium Vinckei

Reversed-phase h.p.l.c. was used to detect 2,4-dinitrophenylhydrazine-reactive carbonyl products, which excludes malonaldehyde, in malaria-parasite (Plasmodium vinckei)-infected murine red blood cells (RBCs). A number of alkanals, 4-hydroxyalk-2-enals and alka-2,4-dienals were tentatively identified by comparison with authentic standards. The formation of 4-hydroxynon-2-enal, deca-2,4-dienal and hexanal was greater in P. vinckei-infected RBCs than in their uninfected counterparts and was increased by the presence of t-butyl hydroperoxide. Several of these aldehydes have previously been shown to be toxic to various types of cells, including P. falciparum, in vitro. The iron chelator desferrioxamine and the free-radical scavenger butylated hydroxyanisole inhibited the formation of these aldehydes. These experiments demonstrate that products of lipid peroxidation other than malonaldehyde are formed during the exposure of malaria-infected RBCs in vitro to drugs that generate reactive oxygen species and have anti-parasitic activity. The formation of products of this type during the natural course of malaria infection may have implications for the mechanisms underlying intra-RBC parasite death and the tissue damage associated with the disease.

Carbonyl Products of the Gas-Phase Reaction of Ozone with Simple Alkenes

1996 ◽  
Vol 30 (3) ◽  
pp. 975-983 ◽  
Author(s):  
Eric Grosjean ◽  
Jailson Bittencourt de Andrade ◽  
Daniel Grosjean
Keyword(s):  
Gas Phase ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Carbonyl Products

Unexpected Pyrolytic Behaviour of Substituted Benzo[c]thiopyran and Thieno[2,3-c]thiopyran S,S-dioxides

2014 ◽  
Vol 67 (9) ◽  
pp. 1288 ◽  
Author(s):  
R. Alan Aitken ◽  
Clémence Hauduc ◽  
M. Selim Hossain ◽  
Emily McHale ◽  
Adrian L. Schwan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ring Expansion ◽  
Hydrogen Atom Transfer ◽  
Membered Ring ◽  
X Ray ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Higher Temperature ◽  
Intramolecular Hydrogen ◽  
Carbonyl Products

Flash vacuum pyrolysis (FVP) of benzo[c]thiopyran S,S-dioxide (1) results in formation of indene and 2-vinylbenzaldehyde as previously described. A range of eight analogues with various substitution patterns are found to behave differently. In general, there is no extrusion of SO2 to give products analogous to indene, but unsaturated carbonyl products analogous to 2-vinylbenzaldehyde are formed in most cases by way of ring expansion to a 7-membered ring sultine, extrusion of SO, and intramolecular hydrogen atom transfer. Other processes observed include formation of anthracene via an isomeric 7-membered sultine with loss of SO, CO and methane or butane, and formation of 4-ethylidene-4,5-dihydrocyclobuta[b]thiophenes by way of SO loss, a radical rearrangement, and extrusion of acetone. The analogues with a halogen substituent at position 8 on the benzene ring require a higher temperature to react and give naphthalene resulting from net elimination of HX and SO2. The X-ray crystal structure of 1 is also reported.

EFFECT OF INSULIN SHOCK ON OXIDATIVE MODIFICATION OF PROTEINS IN THE NERVOUS TISSUE OF THE BRAIN OF LABORATORY RATS

2020 ◽  
Vol 6(72) (1) ◽  
pp. 110-124
Author(s):  
V. A. Nikolskaya ◽  
I. V. Cheretaev
Keyword(s):  
Free Radical ◽  
Nervous Tissue ◽  
Study Groups ◽  
Oxidative Modification ◽  
Laboratory Animals ◽  
Intact Group ◽  
Laboratory Rats ◽  
Insulin Shock ◽  
Protein Molecules ◽  
Carbonyl Products

The rationale for the study of the formation of products of oxidative modification of proteins (OMP) in the nervous tissue in an experimental study of the effects of insulin shock was the literature data indicating that, oxidative destruction of proteins is one of the early indicators of tissue damage. The OMP considered as a factor in the pathogenesis of nervous tissue in many diseases. In some studies, there is information about the effect of experimental GP on oxidative processes in blood serum, red blood cells, adrenal glands and some other tissues, but the effect of this pathology on the processes of free radical oxygenation in the nervous tissue not studied. The purpose of this article was to evaluate changes in the level of OMP in the nervous tissue of laboratory rats under the influence of insulin shock. The experiment was performed on 32 sexually mature mongrel male rats weighing 380–400 g (age 6 months), divided into 4 groups of 8 individuals: control (intact) group, group 1-laboratory animals exposed to a single insulin shock (1 time per day, 1 day); group 2 – laboratory rats exposed to a double insulin shock (1 time per day, 2 days); group 3 – laboratory rats exposed to triple exposure to insulin shock (1 time per day, 3 days). Rats of the experimental groups insulin (3.5 Units) subcutaneously were injected. The presence of hypoglycemic coma determined by the appearance of convulsions. Animals that are intact at this time remained in their cells. Experimental animals slaughtered by decapitation on a guillotine. The material for research was a homogenate of nervous tissue obtained by the method Of Kutlubaev M. A. and co-authors. The study of the level of OMB in nervous tissue was performed using the Dubinina E. E. method, based on the reaction of oxidized amino acid residues of protein with 2,4-dinitrophenylhydrazine (2,4 – DNFG) with the formation of anhydrous 2,4 – DNFG. Measurements of supernatant extinction at wavelengths (λ) of 356, 370, 430 and 530 nm performed using a 5400-UV spectrophotometer (Ekros-Analytica, Russia). Statistical processing of the experiment results performed using the student’s parametric t-test, since the experimental data obeyed the law of normal distribution. It was found, that insulin shock and experimental hyperinsulinemia (HI) contributed to a decrease in free radical protein oxidation in rat nervous tissue homogenate, reducing the total level of OMP carbonyl products in all the study groups exposed to insulin shock: in the 1st group – by 37.6 % (n=8; p≤0.01), in the 2nd group – by 40.4 % (n=8; p≤0.01), in the 3rd group – by 40.8 % (n=8; p≤0.01). Experimental HI causes significant changes in the level of OMP products in the nervous tissue of laboratory animals, which expressed in a decrease in aldehyde and ketone derivatives of both the main and neutral characters in comparison with the indicators of the intact group. In all three groups with experimental HI, compared with the intact group, there was a significant decrease in primary and secondary carbonyl products of OMP, which indicates that free radical oxidation processes associated with both fragmentation of protein molecules and their aggregation suppressed under conditions of insulin shock. At one- and three-time exposure to HI, primary markers of oxidative stress, formed mainly due to fragmentation of protein molecules, prevailed among the carbonyl products of OMP in the nervous tissue. The content of primary and secondary carbonyl products was almost equal when the HI applied twice, which indicates that the processes of fragmentation and aggregation of protein molecules were almost the same under these conditions. In all three experimental groups, compared with the intact group, there was a significant decrease in carbonyl products of both neutral and basic nature due to a decrease in free radical damage to neutral and basic amino acids of protein molecules. In all the study groups, including the intact group, the level of OMPo was significantly lower than the level of OMPn. The most pronounced differences between the level of carbonyl products of OMP and OMPo were observed with three-fold HI, and the least pronounced-with a single one. With increasing duration of insulin shock, the spectrum of carbonyl products of OMP shifted towards increasing the content of the main products, as the role of the main amino acids as targets for damage to protein molecules by free radicals increased.

scholarly journals New Pathways for Formation of Acids and Carbonyl Products in Low-Temperature Oxidation: The Korcek Decomposition of γ-Ketohydroperoxides

2013 ◽  
Vol 135 (30) ◽  
pp. 11100-11114 ◽  
Author(s):  
Amrit Jalan ◽  
Ionut M. Alecu ◽  
Rubén Meana-Pañeda ◽  
Jorge Aguilera-Iparraguirre ◽  
Ke R. Yang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Carbonyl Products

scholarly journals Antioxidation capacity of Maillard systems with carbonyl products of sugar fragmentation

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S60-S63 ◽  
Author(s):  
K. Cejpek ◽  
L. Jarolímová ◽  
J. Velíšek
Keyword(s):  
Amino Acids ◽  
Carbonyl Compound ◽  
Antioxidative Activity ◽  
Reducing Power ◽  
Aqueous Mixtures ◽  
Electrochemically Active ◽  
Reducing Activity ◽  
Colour Development ◽  
Carbonyl Products

A role of reactive C<sub>2</sub>-C<sub>5</sub> α-dicarbonyl and α-hydroxycarbonyl products of sugar fragmentation in the development of antioxidative activity (AOA) was investigated after heating in 0.5M binary aqueous mixtures with amino acids. Several kinetic and activity parameters related to the development of reducing power in the systems with different carbonyl fragments as well as glucose were evaluated and compared. The formation of electrochemically active compounds was correlated with colour development. To assess the antioxidation effects more properly, several different methods were used for AOA evaluation of the systems tested in addition to the HPLC-ECD method. Tests with scavenging of radicals or assays evaluating oxidation in different media (hydrophobic, hydrophilic, emulsions) were employed. Biacetyl was found as by far the most powerful precursor of reducing activity among the fragments tested. The major products possessing reducing power were isolated and characterized revealing dihydroxy dimethylbenzene structures. Based on the comparison of the same concentrations of BHA and a parent carbonyl compound, AOA found by different methods in the most powerful systems is fully comparable with BHA efficiency.

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