scholarly journals Redox-Neutral Organometallic Elementary Steps at Bismuth: Catalytic Synthesis of Aryl Sulfonyl Fluorides

2021 ◽  
Author(s):  
Marc Magre ◽  
Josep Cornella
Keyword(s):  
Catalytic Synthesis ◽  
Elementary Steps

Catalytic Synthesis of Cyclic Guanidines via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Shunya Ohuchi ◽  
Hiroki Koyama ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Catalytic Synthesis ◽  
Membered Ring ◽  
Biologically Active ◽  
Atom Transfer ◽  
Powerful Method ◽  
Protective Groups ◽  
The Common

A catalytic synthesis of cyclic guanidines, which are found in many biologically active compounds and natu-ral products, was developed, wherein transition-metal hydrogen atom transfer and radical-polar crossover were employed. This mild and functional-group tolerant process enabled the cyclization of alkenyl guanidines bearing common protective groups, such as Cbz and Boc. This powerful method not only provided the common 5- and 6-membered rings but also an unusual 7-membered ring. The derivatization of the products afforded various heterocycles. We also investigated the se-lective cyclization of mono-protected or hetero-protected (TFA and Boc) alkenyl guanidines and their further derivatiza-tions.

A Systematic DFT Study of Two Elementary Steps Involving Hydrogen Peroxide and the Hydroxyl Radical in the Fenton Reaction

2018 ◽  
Author(s):  
Danilo Carmona ◽  
David Contreras ◽  
Oscar A. Douglas-Gallardo ◽  
Stefan Vogt-Geisse ◽  
Pablo Jaque ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Ab Initio ◽  
Fenton Reaction ◽  
Basis Set ◽  
Basis Sets ◽  
Dft Methods ◽  
Elementary Steps ◽  
Oxygen Oxygen ◽  
Complete Basis Set

The Fenton reaction plays a central role in many chemical and biological processes and has various applications as e.g. water remediation. The reaction consists of the iron-catalyzed homolytic cleavage of the oxygen-oxygen bond in the hydrogen peroxide molecule and the reduction of the hydroxyl radical. Here, we study these two elementary steps with high-level ab-initio calculations at the complete basis set limit and address the performance of different DFT methods following a specific classification based on the Jacob´s ladder in combination with various Pople's basis sets. Ab-initio calculations at the complete basis set limit are in agreement to experimental reference data and identified a significant contribution of the electron correlation energy to the bond dissociation energy (BDE) of the oxygen-oxygen bond in hydrogen peroxide and the electron affinity (EA) of the hydroxyl radical. The studied DFT methods were able to reproduce the ab-initio reference values, although no functional was particularly better for both reactions. The inclusion of HF exchange in the DFT functionals lead in most cases to larger deviations, which might be related to the poor description of the two reactions by the HF method. Considering the computational cost, DFT methods provide better BDE and EA values than HF and post--HF methods with an almost MP2 or CCSD level of accuracy. However, no systematic general prediction of the error based on the employed functional could be established and no systematic improvement with increasing the size in the Pople's basis set was found, although for BDE values certain systematic basis set dependence was observed. Moreover, the quality of the hydrogen peroxide, hydroxyl radical and hydroxyl anion structures obtained from these functionals was compared to experimental reference data. In general, bond lengths were well reproduced and the error in the angles were between one and two degrees with some systematic trend with the basis sets. From our results we conclude that DFT methods present a computationally less expensive alternative to describe the two elementary steps of the Fenton reaction. However, choice of approximated functionals and basis sets must be carefully done and the provided benchmark allows a systematic validation of the electronic structure method to be employed

Synthesis of 3,4-Dihydropyrimidin-2(1H)-one Derivatives Using Activated Montmorillonite as Catalyst

2018 ◽  
Vol 16 (1) ◽  
pp. 59-65
Author(s):  
Sofiane Mekki ◽  
Lahcen Krabia ◽  
Saleh Mahmoud Saleh Mohamed ◽  
Salima Saidi-Besbes
Keyword(s):  
Catalytic Synthesis ◽  
Montmorillonite Clays

An efficient catalytic synthesis of 4-aryl-3,4-dihydropyrimidine-2(1H)-one derivatives using copper (II), iron (III) and zinc (II) exchanged montmorillonite clays as a catalyst is described. The desired products were obtained in good yields.

Catalytic Synthesis of Bulk Hydrophilic Acetaldehyde-Modified Polyamide 46

2014 ◽  
Vol 11 (2) ◽  
pp. 288-294
Author(s):  
Hamidreza Barghi ◽  
Mikael Skrifvars ◽  
Mohammad Taherzadeh
Keyword(s):  
Catalytic Synthesis

Catalytic synthesis of sulfur and phosphorus compounds via atom-economic reactions

2020 ◽  
Vol 30 (2) ◽  
pp. 129-138
Author(s):  
Shin-ichi Kawaguchi ◽  
Yuki Yamamoto ◽  
Akiya Ogawa
Keyword(s):  
Catalytic Synthesis ◽  
Phosphorus Compounds

Insights into the Solubility of Carbon Dioxide in Grafted Mesoporous Silica for the Catalytic Synthesis of Cyclic Carbonates by Nanoconfinement

2021 ◽  
Author(s):  
Shahab Boroun ◽  
Abolfazl Alizadeh Sahraei ◽  
Abdol Hadi Mokarizadeh ◽  
Houshang Alamdari ◽  
Frédéric-Georges Fontaine ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Mesoporous Silica ◽  
Catalytic Synthesis ◽  
Cyclic Carbonates
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