ChemInform Abstract: Tandem Synthesis of Polysubstituted Pyridines via the Indium(III)-Triflate-Catalyzed Cycloaddition/Oxidative Aromatization of Blaise Reaction Intermediates with α,β-Unsaturated Ketones.

ChemInform ◽  
2015 ◽  
Vol 46 (13) ◽  
pp. no-no
Author(s):  
Zi Xuan ◽  
Kris Rathwell ◽  
Sang-gi Lee
Keyword(s):  
Reaction Intermediates ◽  
Unsaturated Ketones ◽  
Oxidative Aromatization ◽  
Tandem Synthesis

Practical Synthesis of Functionalized Chromeno[3,4-c]pyridine Derivatives via a CuCl2-Catalyzed Tandem Reaction of the Blaise Reaction Intermediates and 3-Cyanocoumarins

Synlett ◽  
2018 ◽  
Vol 29 (07) ◽  
pp. 959-963
Author(s):  
Jian-Jun Li ◽  
Zhiwei Chen ◽  
Yangyang Fan ◽  
Lei Zheng ◽  
Zhaohai Yang
Keyword(s):  
Michael Addition ◽  
Functional Group ◽  
Tandem Reaction ◽  
Pyridine Derivatives ◽  
Reaction Intermediates ◽  
Reaction Conditions ◽  
Purification Technique ◽  
Aromatization Reaction ◽  
Oxidative Aromatization ◽  
Practical Synthesis

This work discloses a novel and efficient protocol for the construction of functionalized chromeno[3,4-c]pyridine derivatives from the Blaise reaction intermediates and 3-cyanocoumarins through a CuCl2-catalyzed sequential Michael addition/intramolecular cyclization/oxidative aromatization reaction. This new method shows the advantages of mild reaction conditions, easy workup, nonchromatographic purification technique, good functional group tolerance, and moderate to good yields.

Analyzing reactions of single mechanoenzyme molecules by light microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 426-427
Author(s):  
Jeff Gelles
Keyword(s):  
Image Processing ◽  
Reaction Mechanisms ◽  
Transient State ◽  
Nanometer Scale ◽  
Reaction Intermediates ◽  
Enzyme Molecule ◽  
Directed Movement ◽  
Enzyme Molecules ◽  
Individual Enzyme ◽  
Single Reaction

Mechanoenzymes are enzymes which use a chemical reaction to power directed movement along biological polymer. Such enzymes include the cytoskeletal motors (e.g., myosins, dyneins, and kinesins) as well as nucleic acid polymerases and helicases. A single catalytic turnover of a mechanoenzyme moves the enzyme molecule along the polymer a distance on the order of 10−9 m We have developed light microscope and digital image processing methods to detect and measure nanometer-scale motions driven by single mechanoenzyme molecules. These techniques enable one to monitor the occurrence of single reaction steps and to measure the lifetimes of reaction intermediates in individual enzyme molecules. This information can be used to elucidate reaction mechanisms and determine microscopic rate constants. Such an approach circumvents difficulties encountered in the use of traditional transient-state kinetics techniques to examine mechanoenzyme reaction mechanisms.

1,4-Reductions of α,β-Unsaturated Ketones and Aldehydes via in situ Generated Hydridocuprates

Synlett ◽  
1989 ◽  
Vol 1989 (01) ◽  
pp. 64-66 ◽  
Author(s):  
Bruce H. Lipshutz ◽  
Christopher S. Ung ◽  
Saumitra Sengupta
Keyword(s):  
Unsaturated Ketones

Lateral Adsorbate Interactions Inhibit HCOO- While Promoting CO Selectivity for CO2 Electrocatalysis on Ag

2018 ◽  
Author(s):  
Divya Bohra ◽  
Isis Ledezma-Yanez ◽  
Guanna Li ◽  
Wiebren De Jong ◽  
Evgeny A. Pidko ◽  
...  
Keyword(s):  
Electrochemical Reduction ◽  
Experimental Approach ◽  
Decisive Role ◽  
Experimental Methods ◽  
Reaction Intermediates ◽  
Intermediate Species ◽  
Experimental Knowledge ◽  
Complex Interactions ◽  
Ag Catalysts

<p>The analysis presented in this manuscript helps bridge an important fundamental discrepancy between the existing theoretical and experimental knowledge regarding the performance of Ag catalysts for CO<sub>2</sub> electrochemical reduction (CO<sub>2</sub>ER). The results demonstrate how the intermediate species *OCHO is formed readily en-route the HCOO<sup>– </sup>pathway and plays a decisive role in determining selectivity of a predominantly CO producing catalyst such as Ag. Our theoretical and experimental approach develops a better understanding of the nature of competition as well as the complex interactions between the reaction intermediates leading to CO, HCOO<sup>–</sup> and H<sub>2</sub> during CO<sub>2</sub>ER.</p><p><br></p><p>Details of computational and experimental methods are present in the Supporting Information provided. </p><p><br></p><p><br></p>

The Synthesis of New Selenium-containing Heterocycles by the Oxidation Reaction of 2,4-Diaryltetrahydro-4H-selenochromenes

2020 ◽  
Vol 24 (15) ◽  
pp. 1663-1668
Author(s):  
Dmitriy Yurievich Direnko ◽  
Boris Ivanovich Drevko ◽  
Yaroslav Borisovich Drevko
Keyword(s):  
Nucleophilic Substitution ◽  
Chlorine Atom ◽  
Oxidation Reaction ◽  
Heterocyclic Fragment ◽  
Oxidative Aromatization

We have explored the reactions of tetrahydro-4H-selenochromenes in the presence of phosphoric pentachloride, and synthesized new condensate aroylbenzoselenophenes. During the reactions, tetrahydro-4H-selenochromenes with phosphoric pentachloride underwent oxidative aromatization and nucleophilic substitution for a chlorine atom of one of the protons in the alicyclic fragment. Also, the narrowing of the heterocyclic fragment occurred as in synthesized selenium-containing compounds earlier transformed into the corresponding condensate aroylbenzoselenophenes.

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