To Probe the Origin of Activation Effect of Carboxylic Acid and (+)-NLE in Tridentated Titanium Catalyst Systems

2002 ◽  
Vol 124 (50) ◽  
pp. 14866-14867 ◽  
Author(s):  
Yu Yuan ◽  
Xin Li ◽  
Jie Sun ◽  
Kuiling Ding
Keyword(s):  
Carboxylic Acid ◽  
Activation Effect ◽  
Titanium Catalyst ◽  
Catalyst Systems

scholarly journals Late-Stage β-C(sp3)–H Deuteration of Carboxylic Acids

2021 ◽  
Author(s):  
Alexander Uttry ◽  
Sourjya Mal ◽  
Manuel van Gemmeren
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Late Stage ◽  
Bioactive Molecules ◽  
Wide Range ◽  
Catalyst Systems ◽  
First Time

Carboxylic acid moieties are highly abundant in bioactive molecules. In this study we describe the late-stage β-C(sp<sup>3</sup>)–H deuteration of free carboxylic acids. Based on our finding that the C–H activation with our catalyst systems is reversible, the de-deuteration process was first optimized. The resulting conditions involve ethylenediamine-based ligands, which, amongst other positions, for the first time enables the functionalization of non-activated methylene β-C(sp<sup>3</sup>)–H bonds and can be used to achieve the desired deuteration when using a deuterated solvent. The reported method allows for the functionalization of a wide range of free carboxylic acids with diverse substitution patterns, as well as the late-stage deuteration of bioactive molecules and related frameworks.

The effect of the radical structure in trialkylaluminums on cis polymerization of dienes on titanium catalyst systems

1983 ◽  
Vol 21 (9) ◽  
pp. 2697-2711 ◽  
Author(s):  
S. R. Rafikov ◽  
Yu. B. Monakov ◽  
G. A. Tolstikov ◽  
N. G. Marina ◽  
N. Kh. Minchenkova ◽  
...  
Keyword(s):  
Titanium Catalyst ◽  
Radical Structure ◽  
Catalyst Systems

Copolymerization of butadiene and propylene under the action of iodine-containing titanium catalyst systems

1991 ◽  
Vol 33 (9) ◽  
pp. 1783-1791
Author(s):  
L.V. Smirnova ◽  
L.A. Yatsenko ◽  
A.G. Boldyrev ◽  
S.L. Panasyuk ◽  
Ye.N. Kropacheva
Keyword(s):  
Titanium Catalyst ◽  
Catalyst Systems

Understanding the Roles of Triethylaluminum in Phosphinimide-Supported Titanium Catalyst Systems for Ethylene Polymerization

2019 ◽  
Vol 38 (9) ◽  
pp. 2150-2155 ◽  
Author(s):  
Jared L. Barr ◽  
Amit Kumar ◽  
Davide Lionetti ◽  
Carlos A. Cruz ◽  
James D. Blakemore
Keyword(s):  
Ethylene Polymerization ◽  
Titanium Catalyst ◽  
Catalyst Systems

High time resolution enzyme cytochemistry of rod outer segment

1990 ◽  
Vol 48 (3) ◽  
pp. 878-879
Author(s):  
Takuma Saito ◽  
Toshihiro Takizawa
Keyword(s):  
Enzyme Activities ◽  
Outer Segment ◽  
Rapid Change ◽  
High Time Resolution ◽  
Visual Cell ◽  
Enzyme Cytochemistry ◽  
Activation Effect ◽  
Rod Outer Segment ◽  
Enzymatic Cascades ◽  
Rapid Drop

Cells and tissues live on a number of dynamic metabolic pathways, which are made up of sequential enzymatic cascades.Recent biochemical and physiological studies of vision research showed the importance of cGMP metabolism in the rod outer segment of visual cell, indicat ing that the photon activated rhodopsin exerts activation effect on the GTP binding protein, transducin, and this act ivated transducin further activates phosphodiesterase (PDEase) to result in a rapid drop in cGMP concentration in the cytoplasm of rod outer segment. This rapid drop of cGMP concentration exerts to close the ion channel on the plasma membrane and to stop of inward current brings hyperpolarization and evokes an action potential.These sequential change of enzyme activities, known as cGMP cascade, proceeds quite rapidly within msec order. Such a rapid change of enzyme activities, such as PDEase in rod outer segment, was not a matter of conventional histochemical invest igations.

Fibrinolytic Activity of Cerebro-Spinal Fluid and the Development of Artificial Cerebral Haematomas in Dogs

1969 ◽  
Vol 21 (02) ◽  
pp. 294-303 ◽  
Author(s):  
H Mihara ◽  
T Fujii ◽  
S Okamoto
Keyword(s):  
Cerebrospinal Fluid ◽  
Carboxylic Acid ◽  
Fibrinolytic Activity ◽  
Clinical Implications ◽  
Trans Form ◽  
Plate Method ◽  
Blood Samples ◽  
Fibrin Plate ◽  
The Brain

SummaryBlood was injected into the brains of dogs to produce artificial haematomas, and paraffin injected to produce intracerebral paraffin masses. Cerebrospinal fluid (CSF) and peripheral blood samples were withdrawn at regular intervals and their fibrinolytic activities estimated by the fibrin plate method. Trans-form aminomethylcyclohexane-carboxylic acid (t-AMCHA) was administered to some individuals. Genera] relationships were found between changes in CSF fibrinolytic activity, area of tissue damage and survival time. t-AMCHA was clearly beneficial to those animals given a programme of administration. Tissue activator was extracted from the brain tissue after death or sacrifice for haematoma examination. The possible role of tissue activator in relation to haematoma development, and clinical implications of the results, are discussed.

Stereospecific, Palladium-catalyzed C(sp3)–H Alkenylation and Alkynylation of a Proline Derivative Enabled by 8-Aminoquinoline as a Directing Group

2020 ◽  
Author(s):  
Aleksandra Balliu ◽  
Aaltje Roelofje Femmigje Strijker ◽  
Michael Oschmann ◽  
Monireh Pourghasemi Lati ◽  
Oscar Verho
Keyword(s):  
Carboxylic Acid ◽  
Building Blocks ◽  
Wide Range ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
High Yields ◽  
Vinyl Iodides ◽  
Initial Results

<p>In this preprint, we present our initial results concerning a stereospecific Pd-catalyzed protocol for the C3 alkenylation and alkynylation of a proline derivative carrying the well utilized 8‑aminoquinoline directing group. Efficient C–H alkenylation was achieved with a wide range of vinyl iodides bearing different aliphatic, aromatic and heteroaromatic substituents, to furnish the corresponding C3 alkenylated products in good to high yields. In addition, we were able show that this protocol can also be used to install an alkynyl group into the pyrrolidine scaffold, when a TIPS-protected alkynyl bromide was used as the reaction partner. Furthermore, two different methods for the removal of the 8-aminoquinoline auxiliary are reported, which can enable access to both <i>cis</i>- and <i>trans</i>-configured carboxylic acid building blocks from the C–H alkenylation products.</p>

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