Quantitative Evaluation of the Catalytic Activity of Dendrimers with Only One Active Center at the Core:  Application to the Nitroaldol (Henry) Reaction

2004 ◽  
Vol 126 (16) ◽  
pp. 5243-5252 ◽  
Author(s):  
Aizpea Zubia ◽  
Fernando P. Cossío ◽  
Iñaki Morao ◽  
Marina Rieumont ◽  
Xabier Lopez
Keyword(s):  
Catalytic Activity ◽  
Active Center ◽  
Quantitative Evaluation ◽  
Henry Reaction ◽  
The Core

Polycomb genes role in cancer pathophysiology is offering targets for therapeutics including gene therapy

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Catalytic Activity ◽  
Detailed Understanding ◽  
The Core ◽  
Chromatin Regulators ◽  
Genetic Modifications ◽  
Anti Cancer ◽  
The Many ◽  
The One ◽  
Context Specific ◽  
Study Context

Several phenotypes can come from transcription regulation. Sequence-specific transcription factors are needed to effectively execute transcriptional programs, however they are often not operating alone. Polycomb PcG proteins are a well-known class of chromatin regulators found in Drosophila melanogaster and other species, including humans. As time passed, the concept of a PCG gene or protein shifted from the original phenotypic meaning of mutant flies to the contemporary biochemical description. PCG genes and proteins are under investigation for their critical contributions to physiology and their cancer treatment potential. Adding additional PcG members, with substantial responsibilities in PRC modulation, has opened new routes of inquiry in the issue. It is still needed to discover the many PRC variations' roles and how their catalytic activity is controlled. This review covers mutually exclusive PRC2 variants and employs a technique like the one used for PRC1 variants. Based on current biochemical findings, these classifications are valid. More auxiliary PcG subunit research is needed for now. Moreover, it is unknown how many PRC cell variations occur (hypothetically, there could be more than 100 different PRC variants).In order to fully elucidate the new PcG proteins and complexes, it is necessary to perform comprehensive research. We must study context-specific genetic modifications to better provide remedies. Current anti-cancer drugs target mainly the core subunits and catalytic activity of PRC2 and PRC1, and understanding these functions is critical. Targeting each particular activity that has been deregulated might be rather beneficial. PCG proteins are involved in oncogenesis, tumor suppression, and development/congenital illness as well. PcG involvement in cancer, once revealed, would be intriguing. Successful and effective therapeutic therapies will be helped by a detailed understanding of the pathways that contain PcG proteins.

2-Dihydromethylpiperazinediium-MII(MII= CuII, FeII, CoII, ZnII) double sulfates and their catalytic activity in diastereoselective nitroaldol (Henry) reaction

2013 ◽  
Vol 42 (2) ◽  
pp. 399-406 ◽  
Author(s):  
Houcine Naïli ◽  
Fadhel Hajlaoui ◽  
Tahar Mhiri ◽  
Tatiana C. O. Mac Leod ◽  
Maximilian N. Kopylovich ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Henry Reaction ◽  
Double Sulfates

Tin sulfide and selenide clusters soluble in organic solvents with the core structures of Sn4S6 and Sn4Se6

2015 ◽  
Vol 44 (46) ◽  
pp. 19800-19804 ◽  
Author(s):  
Mingdong Zhong ◽  
Zhi Yang ◽  
Yafei Yi ◽  
Dongxiang Zhang ◽  
Kening Sun ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Organic Solvents ◽  
High Catalytic Activity ◽  
Tin Sulfide ◽  
Chalcogenide Clusters ◽  
Mild Conditions ◽  
The Core

Reactions of LSnCl (1) (L = N(2,6-iPr2C6H3)(SiMe3)) with sulfur and selenium, respectively under mild conditions yielded two tin chalcogenide clusters. The two products show high catalytic activity in ROP catalysis.

Copper(II) coordination polymers of arylhydrazone of 1H-indene-1,3(2H)-dione linked by 4,4′-bipyridineor hexamethylenetetramine: Evaluation of catalytic activity in Henry reaction

Polyhedron ◽  
2017 ◽  
Vol 133 ◽  
pp. 33-39 ◽  
Author(s):  
Gonçalo A.O. Tiago ◽  
Kamran T. Mahmudov ◽  
M. Fátima C. Guedes da Silva ◽  
Ana P.C. Ribeiro ◽  
Fatali E. Huseynov ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Coordination Polymers ◽  
Henry Reaction

scholarly journals Azo-dimethylaminopyridine-functionalized Ni(II)-porphyrin as a photoswitchable nucleophilic catalyst

2020 ◽  
Vol 16 ◽  
pp. 2119-2126
Author(s):  
Jannis Ludwig ◽  
Julian Helberg ◽  
Hendrik Zipse ◽  
Rainer Herges
Keyword(s):  
Catalytic Activity ◽  
Spin State ◽  
Rate Constants ◽  
Green Light ◽  
Lone Pair ◽  
Henry Reaction ◽  
Record Player

We present the synthesis and the photochemical and catalytic switching properties of an azopyridine as a photoswitchable ligand, covalently attached to a Ni(II)-porphyrin. Upon irradiation with 530 nm (green light), the azopyridine switches to the cis configuration and coordinates with the Ni2+ ion. Light of 435 nm (violet) isomerizes the ligand back to the trans configuration, which decoordinates for steric reasons. This so-called record player design has been used previously to switch the spin state of Ni2+ between singlet and triplet. We now use the coordination/decoordination process to switch the catalytic activity of the dimethylaminopyridine (DMAP) unit. DMAP is a known catalyst in the nitroaldol (Henry) reaction. Upon coordination to the Ni2+ ion, the basicity of the pyridine lone pair is attenuated and hence the catalytic activity is reduced. Decoordination restores the catalytic activity. The rate constants in the two switching states differ by a factor of 2.2, and the catalytic switching is reversible.

scholarly journals Conserved tryptophan in the core domain of transglutaminase is essential for catalytic activity

2002 ◽  
Vol 99 (5) ◽  
pp. 2738-2742 ◽  
Author(s):  
S. N. P. Murthy ◽  
S. Iismaa ◽  
G. Begg ◽  
D. M. Freymann ◽  
R. M. Graham ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Core Domain ◽  
The Core

scholarly journals Impact of AlCl3 and FeCl2 Addition on Catalytic Behaviors of TiCl4/MgCl2/THF Catalysts for Ethylene Polymerization and Ethylene/1-Hexene Copolymerization

2018 ◽  
Vol 13 (3) ◽  
pp. 393
Author(s):  
Thanyathorn Niyomthai ◽  
Bunjerd Jongsomjit ◽  
Piyasan Praserthdam
Keyword(s):  
Catalytic Activity ◽  
Active Center ◽  
Chemical Reaction ◽  
Lewis Acids ◽  
Ethylene Polymerization ◽  
Active Sites ◽  
Reaction Engineering ◽  
Chemical Route ◽  
The Impact ◽  
Chemical Reaction Engineering

The present research focuses on elucidating of the impact of Lewis acids including AlCl3 and FeCl2 addition on catalytic behaviors during ethylene polymerization and ethylene/1-hexene copolymerization over the TiCl4/MgCl2/THF catalyst (Cat. A). In this study, the Cat. A with the absence and presence of Lewis acids was synthesized via the chemical route. Then, all catalyst samples were characterized and tested in the slurry polymerization. For ethylene polymerization, using the Cat. A with the presence of AlCl3 apparently gave the highest activity among other catalysts. In addition, the activity of catalysts tended to increase with the presence of the Lewis acids. This can be attributed to an enhancement of active center distribution by the addition of Lewis acids leading to larger amounts of the isolated Ti species. Moreover, with the presence of Lewis acids, the effect of hydrogen on the decreased activity was also less pronounced. Considering ethylene/1-hexene copolymerization, it revealed that the catalyst with the presence of mixed Lewis acids (AlCl3 + FeCl2) exhibited the highest activity. It is suggested that the presence of mixed Lewis acids possibly caused a change in acidity of active sites, which is suitable for copolymerization. However, activities of all catalysts in ethylene/1-hexene copolymerization were lower than those in ethylene polymerization. The effect of hydrogen on the decreased activity for both polymerization and copolymerization system was found to be similar with the presence of Lewis acids. Based on this study, it is quite promising to enhance the catalytic activity by addition of proper Lewis acids, especially when the pressure of hydrogen increases. The characteristics of polymers obtained upon the presence of Lewis acids will be discussed further in more detail.  Copyright © 2018 BCREC Group. All rights reservedReceived: 22nd January 2018; Revised: 18th March 2018; Accepted: 19th March 2018How to Cite: Niyomthai, T., Jongsomjit, B., Praserthdam, P. (2018). Impact of AlCl3 and FeCl2 Addition on Catalytic Behaviors of TiCl4/MgCl2/THF Catalysts for Ethylene Polymerization and Ethylene/1-Hexene Copolymerization. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (3): 393-404 (doi:10.9767/bcrec.13.3.2116.393-404)Permalink/DOI: https://doi.org/10.9767/bcrec.13.3.2116.393-404

scholarly journals Tuning the Core–Shell Structure of Au144@Fe2O3 for Optimal Catalytic Activity for CO Oxidation

2018 ◽  
Vol 148 (8) ◽  
pp. 2315-2324
Author(s):  
Michelle Lukosi ◽  
Chengcheng Tian ◽  
Xinyi Li ◽  
Shannon M. Mahurin ◽  
Harry M. Meyer ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Co Oxidation ◽  
Shell Structure ◽  
Core Shell ◽  
The Core ◽  
Core Shell Structure
Sign in / Sign up

Export Citation Format

Share Document