ChemInform Abstract: The Ternary Amide KLi3(NH2)4: An Important Intermediate in the Potassium Compound-Added Li-N-H Systems.

ChemInform ◽  
2014 ◽  
Vol 45 (31) ◽  
pp. no-no
Author(s):  
Bao-Xia Dong ◽  
Liang Song ◽  
Jun Ge ◽  
Yun-Lei Teng ◽  
Shi-Yang Zhang
Keyword(s):  
Important Intermediate ◽  
Potassium Compound

The ternary amide KLi3(NH2)4: an important intermediate in the potassium compound-added Li–N–H systems

RSC Advances ◽  
2014 ◽  
Vol 4 (21) ◽  
pp. 10702-10707 ◽  
Author(s):  
Bao-Xia Dong ◽  
Liang Song ◽  
Jun Ge ◽  
Yun-Lei Teng ◽  
Shi-Yang Zhang
Keyword(s):  
Formation Mechanism ◽  
Important Intermediate ◽  
Potassium Compound

Formation mechanism of KLi3(NH2)4 as an important intermediate in the potassium compound-added Li–N–H system was clarified.

The Diels-Alder reaction of butadiene with hexacyclic olefins in the synthesis of triamantane

1986 ◽  
Vol 51 (5) ◽  
pp. 1083-1085 ◽  
Author(s):  
Zdeněk Kafka ◽  
Luděk Vodička
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Important Intermediate ◽  
Composition Of Products

The paper describes the composition of products arising from the Diels-Alder reaction of butadiene with hexacyclic olefins (hexacyclo[8,4,0,02,7,03,14,04,8,09,13]tetradec-5-ene and hexacyclo[6,6,0,02,6,05,14,07,12,09,13]tetradec-3-ene) under different conditions. The reaction afforded a mixture of heptacyclic olefins (heptacyclo[8,8,0,02,17,03,11,04,9,012,16,013,18]octadec-6-ene and heptacyclo[8,8,0,02,13,03,11,04,9,012,17,014,18]octadec-6-ene), which is an important intermediate in the synthesis of triamantane.

scholarly journals Selective Styrene Oxidation to Benzaldehyde over Recently Developed Heterogeneous Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1680
Author(s):  
Marta A. Andrade ◽  
Luísa M. D. R. S. Martins
Keyword(s):  
Heterogeneous Catalysts ◽  
Carbon Materials ◽  
Oxygen Species ◽  
Styrene Oxidation ◽  
Reaction Conditions ◽  
Reactive Metal ◽  
Catalytic Systems ◽  
Tert Butyl Hydroperoxide ◽  
Metal Organic ◽  
Important Intermediate

The selective oxidation of styrene under heterogeneous catalyzed conditions delivers environmentally friendly paths for the production of benzaldehyde, an important intermediate for the synthesis of several products. The present review explores heterogeneous catalysts for styrene oxidation using a variety of metal catalysts over the last decade. The use of several classes of supports is discussed, including metal–organic frameworks, zeolites, carbon materials and silicas, among others. The studied catalytic systems propose as most used oxidants tert-butyl hydroperoxide, and hydrogen peroxide and mild reaction conditions. The reaction mechanism proceeds through the generation of an intermediate reactive metal–oxygen species by catalyst-oxidant interactions. Overall, most of the studies highlight the synergetic effects among the metal and support for the activity and selectivity enhancement.

Cdc6p establishes and maintains a state of replication competence during G1 phase

1997 ◽  
Vol 110 (6) ◽  
pp. 753-763 ◽  
Author(s):  
C.S. Detweiler ◽  
J.J. Li
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Transcriptional Repression ◽  
Prolonged Exposure ◽  
S Phase ◽  
Restrictive Temperature ◽  
Yeast Saccharomyces Cerevisiae ◽  
Important Intermediate ◽  
Initiation Of Dna Replication ◽  
And Function

CDC6 is essential for the initiation of DNA replication in the budding yeast Saccharomyces cerevisiae. Here we examine the timing of Cdc6p expression and function during the cell cycle. Cdc6p is expressed primarily between mitosis and Start. This pattern of expression is due in part to posttranscriptional controls, since it is maintained when CDC6 is driven by a constitutively induced promoter. Transcriptional repression of CDC6 or exposure of cdc6-1(ts) cells to the restrictive temperature at mitosis blocks subsequent S phase, demonstrating that the activity of newly synthesized Cdc6p is required each cell cycle for DNA replication. In contrast, similar perturbations imposed on cells arrested in G(1) before Start have moderate or no effects on DNA replication. This suggests that, between mitosis and Start, Cdc6p functions in an early step of initiation, effectively making cells competent for replication. Prolonged exposure of cdc6-1(ts) cells to the restrictive temperature at the pre-Start arrest eventually does cripple S phase, indicating that Cdc6p also functions to maintain this initiation competence during G(1). The requirement for Cdc6p to establish and maintain initiation competence tightly correlates with the requirement for Cdc6p to establish and maintain the pre-replicative complex at a replication origin, strongly suggesting that the pre-replicative complex is an important intermediate for the initiation of DNA replication. Confining assembly of the complex to G(1) by restricting expression of Cdc6p to this period may be one way of ensuring precisely one round of replication per cell cycle.

scholarly journals Homocysteine Modification in Protein Structure/Function and Human Disease

2019 ◽  
Vol 99 (1) ◽  
pp. 555-604 ◽  
Author(s):  
Hieronim Jakubowski
Keyword(s):  
Vascular Complications ◽  
Premature Death ◽  
Epidemiological Studies ◽  
Brain Diseases ◽  
Disease Phenotypes ◽  
The Past ◽  
Nonprotein Amino Acid ◽  
Important Intermediate ◽  
One Carbon Metabolism ◽  
The 1960S

Epidemiological studies established that elevated homocysteine, an important intermediate in folate, vitamin B12, and one carbon metabolism, is associated with poor health, including heart and brain diseases. Earlier studies show that patients with severe hyperhomocysteinemia, first identified in the 1960s, exhibit neurological and cardiovascular abnormalities and premature death due to vascular complications. Although homocysteine is considered to be a nonprotein amino acid, studies over the past 2 decades have led to discoveries of protein-related homocysteine metabolism and mechanisms by which homocysteine can become a component of proteins. Homocysteine-containing proteins lose their biological function and acquire cytotoxic, proinflammatory, proatherothrombotic, and proneuropathic properties, which can account for the various disease phenotypes associated with hyperhomocysteinemia. This review describes mechanisms by which hyperhomocysteinemia affects cellular proteostasis, provides a comprehensive account of the biological chemistry of homocysteine-containing proteins, and discusses pathophysiological consequences and clinical implications of their formation.

Photolysis of Thiopurines in the Presence of Oxygen+

1981 ◽  
Vol 36 (12) ◽  
pp. 1628-1631 ◽  
Author(s):  
Grażyna Wenska ◽  
Stefan Paszyc
Keyword(s):  
Singlet Oxygen ◽  
Sulfonic Acid ◽  
Tert Butanol ◽  
Important Intermediate

Abstract Irradiation (λ > 290 nm) of 6-thiopurine and some 9-substituted 6-thiopurines in oxygen saturated tert-butanol leads to hypoxanthine, purine and purine-6-sulfonic acid or their substituted derivatives. Purine and hypoxanthine formation can be sensitized with dyes. The reaction of 6-thiopurine with singlet oxygen has also been performed with purine and hypoxanthine among other products. It seems however that 1O2 is not an important intermediate in the photooxygenation. The photoreaction may have some synthetic value. Hypoxanthines (~50%) or purines (35-45%) were obtained depending on the solvent used.

Di-imide: Some Physical and Chemical Properties, and the Kinetics and Stoichiometry of the Gas-phase Decomposition

1973 ◽  
Vol 51 (21) ◽  
pp. 3605-3619 ◽  
Author(s):  
C. Willis ◽  
R. A. Back
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Chemical Properties ◽  
Phase Decomposition ◽  
Important Intermediate ◽  
Long Lifetime ◽  
Physical And Chemical ◽  
Text Formation ◽  
Kinetics Of

Preparation of di-imide by passing hydrazine vapor through a microwave discharge yields mixtures with NH3 containing typically about 15% N2H2, estimated from the gases evolved on decomposition. The behavior of the mixture (which melts at −65 °C) on warming from −196 to −30 °C suggests a strong interaction between the components. Measurements of magnetic susceptibility and e.p.r. experiments showed that N2H2 is not strongly paramagnetic, which with other observations points to a singlet rather than a triplet ground-state.Di-imide can be vaporized efficiently, together with NH3, by rapid warming, and the vapor is surprisingly long-lived, with a typical half-life of several minutes at room temperature. The near-u.v. (3200–4400 Å) absorption spectrum of the vapor was photographed; it shows well-defined but diffuse bands, with εmax = 6(± 3) at 3450 Å.Di-imide decomposes at room temperature in two ways:[Formula: see text][Formula: see text]Formation of NH3 was not observed but cannot be ruled out. The decomposition of the vapor is complicated by a sizeable and variable decomposition that occurs rapidly during the vaporization. The stoichiometry of this and the vapor-phase decomposition depends on total pressure and di-imide concentration. The kinetics of the decomposition of the vapor were studied from 22 to 200 °C by following the disappearance of N2H2 by absorption of light at 3450 Å, or the formation of N2H4 by absorption at 2400 Å, and by mass spectrometry. The kinetics are complex and can be either first- or second-order, or mixed, depending on surface conditions. The effect of olefin additives on the decomposition was studied, and is also complex.Mechanisms for the decomposition are discussed, including the possible role of trans-cis isomerization. The relatively long lifetime found for di-imide in the gas phase suggests that it may be an important intermediate in many reactions of hydronitrogen systems.

scholarly journals Sporting myths: the REAL role of lactate during exercise

2016 ◽  
Vol 19 (5) ◽  
Author(s):  
T Mann
Keyword(s):  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Endurance Performance ◽  
Post Exercise ◽  
Early Exercise ◽  
Important Intermediate ◽  
Lactate Formation ◽  
Exercise Muscle

Background. Lactate or, as it was customarily known, ‘lactic acid’ was one of the first molecules to attract the attention of early exercise scientists, mainly because blood lactate concentration could be measured and was shown to increase with increasing exercise intensity. This connection resulted in lactate being associated with numerous other events associated with high-intensity exercise including muscle cramps, fatigue, acidosis and post-exercise muscle soreness. Nobel prize-winning research by AV Hill and Otto Meyerhof provided a rational explanation linking lactate to anaerobiosis and acidosis, which resulted in this relationship being widely accepted as fact. It was only following isotopic tracer studies of George Brooks and others that the true role of lactate during rest and exercise was revealed. Conclusions. Lactate is now acknowledged as an important intermediate of carbohydrate metabolism, taken up from the blood by tissues such as skeletal and cardiac muscle as a substrate for oxidation. Furthermore, lactate formation consumes a proton, thereby buffering against muscle acidosis. For this reason, lactate production forms an essential aid to endurance performance rather than a hindrance.

scholarly journals The Emerging Application of Itaconate: Promising Molecular Targets and Therapeutic Opportunities

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiaqi Lin ◽  
Jinxuan Ren ◽  
Dave Schwinn Gao ◽  
Yi Dai ◽  
Lina Yu
Keyword(s):  
Structural Characteristics ◽  
Tricarboxylic Acid Cycle ◽  
Immune Response Gene ◽  
Future Research ◽  
Response Gene ◽  
Biological Regulation ◽  
Important Intermediate ◽  
Cellular Immune ◽  
Substrate Proteins ◽  
Intermediate Metabolite

Metabolites have recently been found to be involved in significant biological regulation and changes. Itaconate, an important intermediate metabolite isolated from the tricarboxylic acid cycle, is derived from cis-aconitate decarboxylation mediated by immune response gene 1 in mitochondrial matrix. Itaconate has emerged as a key autocrine regulatory component involved in the development and progression of inflammation and immunity. It could directly modify cysteine sites on functional substrate proteins which related to inflammasome, signal transduction, transcription, and cell death. Itaconate can be a connector among immunity, metabolism, and inflammation, which is of great significance for further understanding the mechanism of cellular immune metabolism. And it could be the potential choice for the treatment of inflammation and immune-related diseases. This study is a systematic review of the potential mechanisms of metabolite associated with different pathology conditions. We briefly summarize the structural characteristics and classical pathways of itaconate and its derivatives, with special emphasis on its promising role in future clinical application, in order to provide theoretical basis for future research and treatment intervention.

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