scholarly journals Zirconium-catalysed direct substitution of alcohols: enhancing the selectivity by kinetic analysis

2021 ◽  
Author(s):  
Cristiana Margarita ◽  
Piret Villo ◽  
Hernando Tuñon ◽  
Oscar Dalla-Santa ◽  
David Camaj ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Direct Substitution ◽  
Selective Formation

Kinetic analysis was used as a tool for rational optimization of catalytic direct substitution of alcohols to enable selective formation of ethers, thioethers, and Friedel–Crafts alkylation products using a moisture-tolerant and commercially available Zr complex.

scholarly journals Selective Formation of Sed5p-containing SNARE Complexes Is Mediated by Combinatorial Binding Interactions

2001 ◽  
Vol 12 (3) ◽  
pp. 521-538 ◽  
Author(s):  
Marco M.K. Tsui ◽  
William C.S. Tai ◽  
David K. Banfield
Keyword(s):  
Protein Transport ◽  
Snare Proteins ◽  
Functional Roles ◽  
Binding Partners ◽  
Vitro Binding ◽  
Direct Substitution ◽  
Sensitive Factor ◽  
Selective Formation

Sed5p is the only syntaxin family member required for protein transport through the yeast Golgi and it is known to bind up to nine other soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins in vivo. We describe in vitro binding experiments in which we identify ternary and quaternary Sed5p-containing SNARE complexes. The formation of SNARE complexes among these endoplasmic reticulum- and Golgi-localized proteins requires Sed5p and is syntaxin-selective. In addition, Sed5p-containing SNARE complexes form selectively and this selectivity is mediated by Sed5p-containing intermediates that discriminate among subsequent binding partners. Although many of these SNAREs have overlapping distributions in vivo, the SNAREs that form complexes with Sed5p in vitro reflect their functionally distinct locales. Although SNARE–SNARE interactions are promiscuous and a single SNARE protein is often found in more than one complex, both the biochemical as well as genetic analyses reported here suggest that this is not a result of nonselective direct substitution of one SNARE for another. Rather our data are consistent with the existence of multiple (perhaps parallel) trafficking pathways where Sed5p-containing SNARE complexes play overlapping and/or distinct functional roles.

Kinetic Aspects of the Interaction of Blood Clotting Enzymes

1965 ◽  
Vol 13 (01) ◽  
pp. 155-175 ◽  
Author(s):  
H. C Hemker ◽  
P.W Hemker ◽  
E. A Loeliger
Keyword(s):  
Kinetic Analysis ◽  
Enzyme Kinetics ◽  
Blood Clotting ◽  
Enzyme System ◽  
Enzyme Kinetic ◽  
Clotting Time ◽  
Standard Methods

SummaryApplication of the methods of enzyme-kinetic analysis to the results of clotting tests is feasible and can yield useful results. However, the standard methods of enzyme kinetics are not applicable without modifications imposed by the peculiarities of the blood-clotting enzyme system. The influence of the following complicating circumstances is calculated :1. Substrate is not present in excess.2. Only relative measures exist for concentrations of substrate or enzymes.3. Enzymes and substrates are often added together.4. Reagents are not pure.5. Clotting-time is our only measure for clotting-velocity.Formulas are deduced, which makes it possible to recognize the effect of these complications.

Kinematic and Kinetic Analysis of One-hand and Foot Wheelchair Driving.

1995 ◽  
Vol 32 (4) ◽  
pp. 225-231 ◽  
Author(s):  
Toru HARIGAI ◽  
Shinya KIMURA ◽  
Shuichi KAKURAI
Keyword(s):  
Kinetic Analysis

Metal-Metal Cooperative Bond Activation by Heterobimetallic Alkyl, Aryl, and Acetylide PtII/CuI Complexes

2020 ◽  
Author(s):  
Shubham Deolka ◽  
Orestes Rivada Wheelaghan ◽  
Sandra Aristizábal ◽  
Robert Fayzullin ◽  
Shrinwantu Pal ◽  
...  
Keyword(s):  
Alkyl Group ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Terminal Alkyne ◽  
Alkyl Aryl ◽  
Metal Metal ◽  
The Stability ◽  
Selective Formation ◽  
Organoplatinum Compounds

We report selective formation of heterobimetallic PtII/CuI complexes that demonstrate how facile bond activation processes can be achieved by altering reactivity of common organoplatinum compounds through their interaction with another metal center. The interaction of the Cu center with Pt center and with a Pt-bound alkyl group increases the stability of PtMe2 towards undesired rollover cyclometalation. The presence of the CuI center also enables facile transmetalation from electron-deficient tetraarylborate [B(ArF)4]- anion and mild C-H bond cleavage of a terminal alkyne, which was not observed in the absence of an electrophilic Cu center. The DFT study indicates that the role of Cu center acts as a binding site for alkyne substrate, while activating its terminal C-H bond.

Gold Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Reaction Pathways to Access 1,3-Aminoalcohols, 3-Hydroxyketones or 3-Aminoketones

2018 ◽  
Author(s):  
Victor Laserna ◽  
Tom Sheppard
Keyword(s):  
Gold Catalysis ◽  
Reaction Pathways ◽  
High Yield ◽  
Reaction Conditions ◽  
Propargylic Alcohols ◽  
Catalytic Quantity ◽  
Selective Formation ◽  
General Method

A versatile approach to the valorization of propargylic alcohols is reported, enabling controlled access to three different products from the same starting materials. Firstly, a general method for the hydroamination of propargylic alcohols with anilines is described using gold catalysis to give 3-hydroxy imines with complete regioselectivity. These 3-hydroxyimines can be reduced to give 1,3-aminoalcohols with high syn seletivity. Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway.<br>

A New Adsorption Rate Equation in Batch Systems

2018 ◽  
Author(s):  
yongson hong ◽  
Kye-Ryong Sin ◽  
Jong-Su Pak ◽  
Chol-Min Pak
Keyword(s):  
Experimental Data ◽  
Kinetic Analysis ◽  
Adsorption Kinetics ◽  
Rate Equation ◽  
Kinetic Models ◽  
Adsorption Kinetic ◽  
Adsorption Rate ◽  
Batch Systems ◽  
New View

<p><b>In this paper, the deficiencies and cause of previous adsorption kinetic models were revealed, new adsorption rate equation has been proposed and its validities were verified by kinetic analysis of various experimental data.</b> <b>This work is a new view on the adsorption kinetics rather than a comment on the previous adsorption papers.</b></p>

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